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ISL81387, ISL41387
Data Sheet November 21, 2007 FN6201.3
15kV ESD Protected, 5V, Dual Protocol (RS-232/RS-485) Transceivers These devices are BiCMOS interface ICs that are user configured as either a single RS-422, RS-485 differential transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver. In RS-232 mode, the on-board charge pump generates RS-232 compliant 5V Tx output levels, from a supply as low as 4.5V. Four small 0.1F capacitors are required for the charge pump. The transceivers are RS-232 compliant, with the Rx inputs handling up to 25V, and the Tx outputs handling 12V. In RS-485 mode, the transceivers support both the RS-485 and RS-422 differential communication standards. The RS-485 receiver features "full failsafe" operation, so the Rx output remains in a high state if the inputs are open or shorted together. The RS-485 transmitter supports up to three data rates, two of which are slew rate limited for problem free communications. The charge pump disables in RS-485 mode, thereby saving power, minimizing noise, and eliminating the charge pump capacitors. Both RS-232, RS-485 modes feature loopback and shutdown functions. The loopback mode internally connects the Tx outputs to the corresponding Rx input, which facilitates the implementation of board level self test functions. The outputs remain connected to the loads during loopback, so connection problems (e.g., shorted connectors or cables) can be detected. The shutdown mode disables the Tx and Rx outputs, disables the charge pump if in RS-232 mode, and places the IC in a low current (20A) mode. The ISL41387 is a QFN packaged device that offers additional functionality, including a lower speed and edge rate option (115kbps) for EMI sensitive designs, or to allow longer bus lengths. It also features a logic supply voltage pin (VL) that sets the VOH level of logic outputs, and the switching points of logic inputs, to be compatible with another supply voltage in mixed voltage systems. The QFN's choice of active high or low Rx enable pins increases design flexibility, allowing Tx/Rx direction control via a single signal by connecting DEN and RXEN together. For a dual port version of these devices, please see the ISL81334, ISL41334 data sheet.
Features
* 5V Powered, User Selectable RS-232 or RS-485, RS-422 Interface Port (Two RS-232 Transceivers or One RS-485, RS-422 Transceiver) * 15kV (HBM) ESD Protected Bus Pins (RS-232 or RS-485) * Flow-Through Pinouts Simplify Board Layouts * Pb-Free (RoHS Compliant) * Large (2.7V) Differential VOUT for Improved Noise Immunity in RS-485, RS-422 Networks * Full Failsafe (Open/Short) Rx in RS-485, RS-422 Mode * Loopback Mode Facilitates Board Self Test Functions * User Selectable RS-485 Data Rates . . . . . . . . . . 20Mbps - Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps - Slew Rate Limited (ISL41387 Only) . . . . . . . . . 115kbps * Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 650kbps * Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . .35A * QFN Package Saves Board Space (ISL41387 Only) * Logic Supply Pin (VL) Eases Operation in Mixed Supply Systems (ISL41387 Only)
Applications
* Gaming Applications (e.g., Slot machines) * Single Board Computers * Factory Automation * Security Networks * Industrial/Process Control Networks * Level Translators (e.g., RS-232 to RS-422) * Point of Sale Equipment
TABLE 1. SUMMARY OF FEATURES PART NUMBER ISL81387 ISL41387 NO. OF PORTS 1 1 PACKAGE OPTIONS 20 Ld SOIC, 20 Ld SSOP 40 Ld QFN (6mmx6mm) RS-485 DATA RATE (bps) 20M, 460k 20M, 460k, 115k RS-232 DATA RATE (kbps) 650 650 VL PIN? NO YES ACTIVE H or L Rx ENABLE? H BOTH LOW POWER SHUTDOWN? YES YES
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright (c) Intersil Americas Inc. 2005, 2007. All Rights Reserved. All other trademarks mentioned are the property of their respective owners.
ISL81387, ISL41387 Ordering Information
PART NUMBER (Note) ISL81387IAZ ISL81387IAZ-T* ISL81387IBZ ISL81387IBZ-T* ISL41387IRZ ISL41387IRZ-T* PART MARKING 81387 IAZ 81387 IAZ ISL81387IBZ ISL81387IBZ 41387 IRZ 41387 IRZ TEMP. RANGE (C) -40 to +85 -40 to +85 -40 to +85 -40 to +85 -40 to +85 -40 to +85 PACKAGE (Pb-Free) 20 Ld SSOP 20 Ld SSOP (Tape and Reel) 20 Ld SOIC 20 Ld SOIC (Tape and Reel) 40 Ld QFN 40 Ld QFN (Tape and Reel) PKG. DWG. # M20.209 M20.209 M20.3 M20.3 L40.6x6 L40.6x6
*Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate PLUS ANNEAL - e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
Pinouts
ISL81387 (20 LD SOIC, SSOP) TOP VIEW
C1+ 1 C1- 2 V+ 3 20 C2+ 19 C218 VCC 17 RA 16 RB 15 DY 14 DZ/SLEW 13 ON 12 RXEN 11 V-
A4 B5 Y6 Z7 485/232 8 DEN 9 GND 10
ISL41387 (40 LD QFN) TOP VIEW
VCC C1+ C2+ C1C2NC NC NC NC 32 VL 31 30 RA 29 RB 28 DY 27 DZ/SLEW 26 NC 25 NC 24 NC 23 NC 22 NC 21 ON 11 485/232 12 DEN 13 NC 14 SPB 15 GND 16 GND 17 RXEN 18 NC 19 V20 RXEN
40 V+ A B Y Z NC NC NC NC NC 1 2 3 4 5 6 7 8 9 10
39
38
37
36
35
34
33
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FN6201.3 November 21, 2007
ISL81387, ISL41387
TABLE 2. ISL81387 FUNCTION TABLE INPUTS 485/232 0 0 0 0 0 0 0 X 1 1 1 1 1 NOTES: 1. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN are high. 2. Loopback is enabled when ON = 0, and DEN = RXEN = 1. ON 1 1 1 1 0 0 0 0 1 X X 1 0 RXEN 0 0 1 1 0 1 1 0 0 0 1 1 1 DEN SLEW 0 1 0 1 1 0 1 0 0 1 0 1 1 N.A. N.A. N.A. N.A. N.A. N.A. N.A. X X 1/0 X 1/0 1/0 RECEIVER OUTPUTS RA High-Z High-Z ON ON High-Z High-Z ON High-Z High-Z High-Z ON ON ON RB High-Z High-Z ON ON High-Z ON ON High-Z High-Z High-Z High-Z High-Z High-Z DRIVER OUTPUTS Y High-Z ON High-Z ON ON ON ON High-Z High-Z ON High-Z ON ON Z High-Z ON High-Z ON High-Z High-Z ON High-Z High-Z ON High-Z ON ON DRIVER SPEED (Mbps) 0.46 0.46 0.46 0.46 0.46 20/0.46 20/0.46 20/0.46 CHARGE PUMPS (Note 1) ON ON ON ON ON ON ON OFF OFF OFF OFF OFF OFF
LOOPBACK (Note 2) OFF OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF ON
MODE RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 Shutdown RS-485 RS-485 RS-485 RS-485 RS-485
ISL81387 Truth Tables
RS-232 TRANSMITTING MODE INPUTS (ON = 1) 485/232 0 0 0 0 0 DEN 1 1 1 1 0 DY 0 0 1 1 X DZ 0 1 0 1 X OUTPUTS Y 1 1 0 0 High-Z Z 1 0 1 0 High-Z 485/232 1 1 1 1 1 DEN 1 1 1 1 0
RS-485 TRANSMITTING MODE INPUTS (ON = 1) DY 0 1 0 1 X SLEW 1 1 0 0 X Y 1 0 1 0 OUTPUTS Z 0 1 0 1 DATA RATE (Mbps) 20 20 0.46 0.46 -
High-Z High-Z
RS-232 RECEIVING MODE INPUTS (ON = 1) 485/232 0 0 0 0 0 0 RXEN 1 1 1 1 1 0 A 0 0 1 1 Open X B 0 1 0 1 Open X OUTPUT RA 1 1 0 0 1 High-Z RB 1 0 1 0 1 High-Z 485/232 1 1 1 1 RXEN 1 1 1 0
RS-485 RECEIVING MODE INPUTS (ON = 1) B-A -40mV -200mV Open or Shorted together X OUTPUT RA 1 0 1 High-Z RB High-Z High-Z High-Z High-Z
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FN6201.3 November 21, 2007
ISL81387, ISL41387
TABLE 3. ISL41387 FUNCTION TABLE INPUTS RXEN and/or RXEN 1 and 0 1 and 0 0 or 1 0 or 1 1 and 0 0 or 1 0 or 1 1 and 0 1 and 0 1 and 0 1 and 0 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 RECEIVER OUTPUTS DRIVER OUTPUTS DRIVER DATA RATE (Mbps) 0.46 0.46 0.46 0.46 0.46 0.46/0.115 20 0.46/0.115 20 0.46/0.115 20
485/232 0 0 0 0 0 0 0 X 1 1 1 1 1 1 1 1 NOTES:
ON 1 1 1 1 0 0 0 0 1 X X X 1 1 0 0
DEN 0 1 0 1 1 0 1 0 0 1 1 0 1 1 1 1
SLEW N.A. N.A. N.A. N.A. N.A. N.A. N.A. X X 0 1 X 0 1 0 1
SPB N.A. N.A. N.A. N.A. N.A. N.A. N.A. X X 1/0 X X 1/0 X 1/0 X
RA High-Z High-Z ON ON High-Z High-Z ON High-Z High-Z High-Z High-Z ON ON ON ON ON
RB High-Z High-Z ON ON High-Z ON ON High-Z High-Z High-Z High-Z High-Z High-Z High-Z High-Z High-Z
Y High-Z ON High-Z ON ON ON ON High-Z High-Z ON ON High-Z ON ON ON ON
Z High-Z ON High-Z ON High-Z High-Z ON High-Z High-Z ON ON High-Z ON ON ON ON
CHARGE PUMPS (Note 3) ON ON ON ON ON ON ON OFF OFF OFF OFF OFF OFF OFF OFF OFF
MODE RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 RS-232 (Note 4) Shutdown RS-485 RS-485 RS-485 RS-485 RS-485 RS-485 RS-485 (Note 4) RS-485 (Note 4)
3. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN is high, or RXEN is low. 4. Loopback is enabled when ON = 0, and DEN = 1, and (RXEN = 1 or RXEN = 0).
ISL41387 Truth Tables
RS-232 TRANSMITTING MODE INPUTS (ON = 1) 485/232 0 0 0 0 0 DEN 1 1 1 1 0 DY 0 0 1 1 X DZ 0 1 0 1 X OUTPUTS Y 1 1 0 0 High-Z Z 1 0 1 0 High-Z 485/232 1 1 1 1 DEN 1 1 1 0
RS-485 TRANSMITTING MODE INPUTS (ON = 1) SLEW 0 0 1 X SPB 0 1 X X DY 0/1 0/1 0/1 X OUTPUTS Y 1/0 1/0 1/0 Z 0/1 0/1 0/1 DATA Mbps 0.115 0.460 20 -
High-Z High-Z
RS-485 RECEIVING MODE INPUTS (ON = 1) OUTPUT B-A -40mV -200mV Open or Shorted together X RA 1 0 1 RB High-Z High-Z High-Z
RS-232 RECEIVING MODE INPUTS (ON = 1) 485/232 RXEN and/or RXEN 0 0 0 0 0 0 0 or 1 0 or 1 0 or 1 0 or 1 0 or 1 1 and 0 A 0 0 1 1 Open X B 0 1 0 1 Open X OUTPUT RA 1 1 0 0 1 RB 1 0 1 0 1
485/232 RXEN and/or RXEN 1 1 1 1 0 or 1 0 or 1 0 or 1 1 and 0
High-Z High-Z
High-Z High-Z
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FN6201.3 November 21, 2007
ISL81387, ISL41387 Pin Descriptions
PIN 485/232 DEN GND NC ON MODE BOTH BOTH BOTH BOTH BOTH FUNCTION Interface Mode Select input. High for RS-485 Mode and low for RS-232 Mode. Driver output enable. The driver outputs, Y and Z, are enabled by bringing DEN high. They are high impedance when DEN is low. Ground connection. No Connection. In RS-232 mode only, ON high enables the charge pumps. ON low, with DEN and RXEN low (and RXEN high if QFN), turns off the charge pumps (in RS-232 mode), and in either mode places the device in low power shutdown. In both modes, when ON is low, and DEN is high, and RXEN is high or RXEN is low, loopback is enabled. Receiver output enable. Rx is enabled when RXEN is high; Rx is high impedance when RXEN is low and, if using the QFN package, RXEN is high. When using the QFN and the active high Rx enable function, RXEN should be high or floating. Active low receiver output enable. Rx is enabled when RXEN is low; Rx is high impedance when RXEN is high and RXEN is low. (i.e., to use active low Rx enable function, tie RXEN to GND). For single signal Tx/Rx direction control, connect RXEN to DEN. Internally pulled high. (QFN only) System power supply input (5V). Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. (QFN only)
RXEN RXEN
BOTH BOTH
VCC VL A
BOTH BOTH
RS-232 Receiver input with 15kV ESD protection. A low on A forces RA high; a high on A forces RA low. RS-485 Inverting receiver input with 15kV ESD protection.
B
RS-232 Receiver input with 15kV ESD protection. A low on B forces RB high; a high on B forces RB low. RS-485 Noninverting receiver input with 15kV ESD protection.
DY
RS-232 Driver input. A low on DY forces output Y high. Similarly, a high on DY forces output Y low. RS-485 Driver input. A low on DY forces output Y high and output Z low. Similarly, a high on DY forces output Y low and output Z high.
DZ SLEW
RS-232 Driver input. A low on DZ forces output Z high. Similarly, a high on DZ forces output Z low. RS-485 Slew rate control. With the SLEW pin high, the drivers run at the maximum slew rate (20Mbps). With the SLEW pin low, the drivers run at a reduced slew rate (460kbps). On the QFN version, works in conjunction with SPB to select one of three RS-485 data rates. Internally pulled high in RS-485 mode. RS-485 Speed control. Works in conjunction with the SLEW pin to select the 20Mbps, 460kbps or 115kbps RS-485 data rate. Internally pulled high. (QFN only) RS-232 Receiver output. RS-485 Receiver output: If B > A by at least -40mV, RA is high; If B < A by -200mV or more, RA is low; RA = High if A and B are unconnected (floating) or shorted together (i.e., full fail-safe).
SPB RA
RB
RS-232 Receiver output. RS-485 Not used. Output is high impedance, and unaffected by RXEN and RXEN.
Y
RS-232 Driver output with 15kV ESD protection. RS-485 Inverting driver output with 15kV ESD protection.
Z
RS-232 Driver output with 15kV ESD protection. RS-485 Noninverting driver output with 15kV ESD protection.
C1+ C1C2+ C2V+ V/
RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode. RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode. RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode. RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode. RS-232 Internally generated positive RS-232 transmitter supply (+5.5V). C3 not needed in RS-485 Mode. RS-232 Internally generated negative RS-232 transmitter supply (-5.5V). C4 not needed in RS-485 Mode.
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FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Operating Circuit
RS-232 MODE WITHOUT LOOPBACK
+5V +5V 0.1F 1 + 2 20 + 19 C1+ C1C2+ C218 VCC V+ 3 + C3 0.1F C4 0.1F + RA C1 0.1F C2 0.1F +
RS-232 MODE WITH LOOPBACK
+
+
0.1F 1 2 20 C1+ C1C2+ C2R 5k
18 VCC V+ 3 + C3 0.1F C4 0.1F + RA 16
C1 0.1F C2 0.1F
V- 11
+
19 4
V- 11 17
A
4 5k 5 5k
R
17
A1
B
16 R
RB
B1
5 5k
R LB Rx
RB
Y
6
D
15
DY DZ VCC
Y
6
D
15
DY DZ VCC
Z VCC
7 D 9 DEN 8 485/232 GND 10 RXEN ON
14 12
Z VCC
7 9 DEN 8 485/232
D
14 12 RXEN
13
VCC
GND 10
ON
13
NOTE: PINOUT FOR SOIC AND SSOP
NOTE: PINOUT FOR SOIC AND SSOP
RS-485 MODE WITHOUT LOOPBACK
RS-485 MODE WITH LOOPBACK
+5V
+
+5V 0.1F 1 C1+ C1C2+ C2R 18 VCC V+ 3 + C3 0.1F C4 0.1F + RA C1 0.1F C2 0.1F A B
+
0.1F 1 C1+ C1C2+ C2R
18 VCC V+ 3 + C3 0.1F C4 0.1F + RA
C1 0.1F C2 0.1F
+
2 20
+
2 20
+
19 4 5
V- 11
+
19 4
V- 11
A B
17
17
5
16 Y Z 6 15 7 D
RB DY 6
LB Rx 16 Y Z 15 7 D RB DY
14 9 VCC VCC 8 DEN 485/232 GND 10 RXEN ON 13 12
SLEW VCC VCC 9 VCC VCC 8 DEN 485/232 GND 10 RXEN ON
14 12
SLEW VCC
13
NOTE: PINOUT FOR SOIC AND SSOP
NOTE: PINOUT FOR SOIC AND SSOP
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FN6201.3 November 21, 2007
ISL81387, ISL41387
Absolute Maximum Ratings (TA = +25C)
VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V VL (QFN Only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VCC + 0.5V Input Voltages All Except A, B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V Input/Output Voltages A, B (Any Mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25V to +25V Y, Z (Any Mode, Note 5) . . . . . . . . . . . . . . . . . . . -12.5V to +12.5V RA, RB (non-QFN Package). . . . . . . . . . . . -0.5V to (VCC + 0.5V) RA, RB (QFN Package) . . . . . . . . . . . . . . . . -0.5V to (VL + 0.5V) Output Short Circuit Duration Y, Z, RA, RB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Thermal Information
Thermal Resistance
JA (C/W)
20 Ld SOIC Package (Note 7) . . . . . . . . . . . . . . . . . 65 20 Ld SSOP Package (Note 7) . . . . . . . . . . . . . . . . 60 40 Ld QFN Package (Note 6). . . . . . . . . . . . . . . . . . 32 Maximum Junction Temperature (Plastic Package) . . . . . . +150C Maximum Storage Temperature Range . . . . . . . . . -65C to +150C Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . .see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . -40C to +85C
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty.
NOTES: 5. One output at a time, IOUT 100mA for 10 mins. 6. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with "direct attach" features. See Tech Brief TB379. 7. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V, C1 - C4 = 0.1F, VL = VCC (for QFN only), Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25C (Note 8). SYMBOL TEST CONDITIONS TEMP MIN (C) (Note 15) TYP MAX (Note 15) UNITS
PARAMETER
DC CHARACTERISTICS - RS-485 DRIVER (485/232 = VCC) Driver Differential VOUT (no load) Driver Differential VOUT (with load) VOD1 VOD2 R = 50 (RS-422) (Figure 1) R = 27 (RS-485) (Figure 1) VOD3 Change in Magnitude of Driver Differential VOUT for Complementary Output States Driver Common-Mode VOUT Change in Magnitude of Driver Common-Mode VOUT for Complementary Output States Driver Short-Circuit Current, VOUT = High or Low Driver Three-State Output Leakage Current (Y, Z) VOD RD = 60, R = 375, VCM = -7V to 12V (Figure 1) R = 27 or 50 (Figure 1) Full Full Full Full Full 2.5 2.2 2 3.1 2.7 2.7 0.01 VCC 5 5 0.2 V V V V V
VOC VOC
R = 27 or 50 (Figure 1) (Note 12) R = 27 or 50 (Figure 1) (Note 12)
Full Full
-
0.01
3.1 0.2
V V
IOS IOZ
-7V (VY or VZ) 12V (Note 10) Outputs Disabled, VCC = 0V or 5.5V VOUT = 12V VOUT = -7V
Full Full Full
35 -150
-
250 150 -
mA A A
DC CHARACTERISTICS - RS-232 DRIVER (485/232 = 0V) Driver Output Voltage Swing Driver Output Short-Circuit Current VO IOS All TOUTS Loaded with 3k to Ground VOUT = 0V Full Full 5.0 -60 +6/-7 25/-35 60 V mA
DC CHARACTERISTICS - LOGIC PINS (i.e., DRIVER AND CONTROL INPUT PINS) Input High Voltage VIH1 VIH2 VIH3 VL = VCC if QFN VL = 3.3V (QFN Only) VL = 2.5V (QFN Only) Full Full Full 2 2 1.5 1.6 1.2 1 V V V
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FN6201.3 November 21, 2007
ISL81387, ISL41387
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V, C1 - C4 = 0.1F, VL = VCC (for QFN only), Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25C (Note 8). (Continued) SYMBOL VIL1 VIL2 VIL3 Input Current IIN1 IIN2 TEST CONDITIONS VL = VCC if QFN VL = 3.3V (QFN Only) VL = 2.5V (QFN Only) Except SLEW, RXEN (QFN), and SPB (QFN) SLEW (Note 13), RXEN (QFN), and SPB (QFN) TEMP MIN (C) (Note 15) Full Full Full Full Full -2 -25 TYP 1.4 1 0.8 MAX (Note 15) UNITS 0.8 0.7 0.5 2 25 V V V A A
PARAMETER Input Low Voltage
DC CHARACTERISTICS - RS-485 RECEIVER INPUTS (485/232 = VCC) Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Input Current (A, B) VTH VTH IIN -7V VCM 12V, Full Failsafe VCM = 0V VCC = 0V or 4.5V to 5.5V VIN = 12V VIN = -7V Receiver Input Resistance RIN -7V VCM 12V, VCC = 0 (Note 11), or 4.5V VCC 5.5V Full 25 Full Full Full -0.2 -0.64 15 35 -0.04 0.8 V mV mA mA k
DC CHARACTERISTICS - RS-232 RECEIVER INPUTS (485/232 = GND) Receiver Input Voltage Range Receiver Input Threshold VIN VIL VIH Receiver Input Hysteresis Receiver Input Resistance VTH RIN VIN = 15V, VCC Powered Up (Note 11) Full Full Full 25 Full -25 2.4 3 1.4 1.9 0.5 5 25 0.8 7 V V V V k
DC CHARACTERISTICS - RECEIVER OUTPUTS (485 OR 232 MODE) Receiver Output High Voltage VOH1 VOH2 VOH3 Receiver Output Low Voltage Receiver Short-Circuit Current Receiver Three-State Output Current VOL IOSR IOZR IO = -2mA (VL = VCC if QFN) IO = -650A, VL = 3V (QFN Only) IO = -500A, VL = 2.5V (QFN Only) IO = 3mA 0V VO VCC Output Disabled, 0V VO VCC (or VL for QFN) Full Full Full Full Full Full 3.5 2.6 2 7 4.6 2.9 2.4 0.1 0.4 85 10 V V V V mA A
POWER SUPPLY CHARACTERISTICS No-Load Supply Current (Note 9) ICC232 ICC485 Shutdown Supply Current ISHDN232 ISHDN485 ESD CHARACTERISTICS Bus Pins (A, B, Y, Z) Any Mode All Other Pins Human Body Model Human Body Model 25 25 15 4 kV kV 485/232 = 0V, ON = VCC 485/232 = VCC, ON = VCC ON = DEN = RXEN = 0V (RXEN = SPB = VCC if QFN) ON = DEN = RXEN = SLEW = 0V (RXEN = VCC, SPB = 0V if QFN) Full Full Full Full 3.7 1.6 5 35 7 5 30 60 mA mA A A
RS-232 DRIVER and RECEIVER SWITCHING CHARACTERISTICS (485/232 = 0V, ALL VERSIONS AND SPEEDS) Driver Output Transition Region Slew Rate SR RL = 3k, Measured From 3V to CL 15pF -3V or -3V to 3V CL 2500pF Full Full 4 18 12 30 V/s V/s
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FN6201.3 November 21, 2007
ISL81387, ISL41387
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V, C1 - C4 = 0.1F, VL = VCC (for QFN only), Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25C (Note 8). (Continued) SYMBOL tr, tf tDPHL tDPLH Driver Propagation Delay Skew Driver Enable Time Driver Disable Time Driver Enable Time from Shutdown Driver Maximum Data Rate Receiver Propagation Delay tDSKEW tDEN tDDIS tDENSD DRD tRPHL tRPLH Receiver Propagation Delay Skew Receiver Maximum Data Rate tRSKEW DRR tRPHL - tRPLH (Figure 7) CL = 15pF RL = 5k, Measured at VOUT = 3V VOUT = 3.0V (Note 14) RL = 3k, CL = 1000pF, One Transmitter Switching CL = 15pF (Figure 7) tDPHL - tDPLH (Figure 6) TEST CONDITIONS RL = 3k, CL = 2500pF, 10% to 90% RL = 3k, CL = 1000pF (Figure 6) TEMP MIN (C) (Note 15) Full Full Full Full 25 25 25 Full Full Full Full Full 0.22 460 0.46 TYP 1.2 1 1.2 240 800 500 20 650 50 40 10 2 MAX (Note 15) UNITS 3.1 2 2 400 120 120 40 s s s ns ns ns s kbps ns ns ns Mbps
PARAMETER Driver Output Transition Time Driver Propagation Delay
RS-485 DRIVER SWITCHING CHARACTERISTICS (FAST DATA RATE (20Mbps), 485/232 = VCC, SLEW = VCC, ALL VERSIONS) Driver Differential Input to Output Delay Driver Output Skew Driver Differential Rise or Fall Time Driver Enable to Output Low Driver Enable to Output High Driver Disable from Output Low Driver Disable from Output High Driver Enable from Shutdown to Output Low Driver Enable from Shutdown to Output High Driver Maximum Data Rate tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2) tSKEW tR, tF tZL tZH tLZ tHZ tZL(SHDN) tZH(SHDN) fMAX RDIFF = 54, CL = 100pF (Figure 2) RDIFF = 54, CL = 100pF (Figure 2) CL = 100pF, SW = VCC (Figure 3) CL = 100pF, SW = GND (Figure 3) CL = 15pF, SW = VCC (Figure 3) CL = 15pF, SW = GND (Figure 3) RL = 500, CL = 100pF, SW = VCC (Figure 3) (Note 14) RL = 500, CL = 100pF, SW = GND (Figure 3) (Note 14) RDIFF = 54, CL = 100pF (Figure 2) Full Full Full Full Full Full Full Full Full Full 15 3 30 0.5 11 27 24 31 24 65 152 30 50 10 20 60 60 60 60 250 250 ns ns ns ns ns ns ns ns ns Mbps
RS-485 DRIVER SWITCHING CHARACTERISTICS (MEDIUM DATA RATE (460kbps), 485/232 = VCC, SLEW = 0V, SPB = VCC (QFN Only), ALL VERSIONS) Driver Differential Input to Output Delay Driver Output Skew Driver Differential Rise or Fall Time Driver Enable to Output Low Driver Enable to Output High Driver Disable from Output Low Driver Disable from Output High Driver Enable from Shutdown to Output Low Driver Enable from Shutdown to Output High Driver Maximum Data Rate tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2) tSKEW tR, tF tZL tZH tLZ tHZ tZL(SHDN) tZH(SHDN) fMAX RDIFF = 54, CL = 100pF (Figure 2) RDIFF = 54, CL = 100pF (Figure 2) CL = 100pF, SW = VCC (Figure 3) CL = 100pF, SW = GND (Figure 3) CL = 15pF, SW = VCC (Figure 3) CL = 15pF, SW = GND (Figure 3) RL = 500, CL = 100pF, SW = VCC (Figure 3) (Note 14) RL = 500, CL = 100pF, SW = GND (Figure 3) (Note 14) RDIFF = 54, CL = 100pF (Figure 2) Full Full Full Full Full Full Full Full Full Full 200 300 490 110 600 30 128 31 24 65 255 2000 1000 400 1100 300 300 60 60 500 500 ns ns ns ns ns ns ns ns ns kbps
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Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V, C1 - C4 = 0.1F, VL = VCC (for QFN only), Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25C (Note 8). (Continued) SYMBOL TEST CONDITIONS TEMP MIN (C) (Note 15) TYP MAX (Note 15) UNITS
PARAMETER
RS-485 DRIVER SWITCHING CHARACTERISTICS (SLOW DATA RATE (115kbps, QFN ONLY), 485/232 = VCC, SLEW = SPB = GND) Driver Differential Input to Output Delay Driver Output Skew Driver Differential Rise or Fall Time Driver Enable to Output Low Driver Enable to Output High Driver Disable from Output Low Driver Disable from Output High Driver Enable from Shutdown to Output Low Driver Enable from Shutdown to Output High Driver Maximum Data Rate tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2) tSKEW tR, tF tZL tZH tLZ tHZ tZL(SHDN) tZH(SHDN) fMAX RDIFF = 54, CL = 100pF (Figure 2) RDIFF = 54, CL = 100pF (Figure 2) CL = 100pF, SW = VCC (Figure 3) CL = 100pF, SW = GND (Figure 3) CL = 15pF, SW = VCC (Figure 3) CL = 15pF, SW = GND (Figure 3) RL = 500, CL = 100pF, SW = VCC (Figure 3) (Note 14) RL = 500, CL = 100pF, SW = GND (Figure 3) (Note 14) RDIFF = 54, CL = 100pF (Figure 2) Full Full Full Full Full Full Full Full Full Full 800 1000 1500 350 2000 32 300 31 24 65 420 800 2500 1250 3100 600 600 60 60 800 800 ns ns ns ns ns ns ns ns ns kbps
RS-485 RECEIVER SWITCHING CHARACTERISTICS (485/232 = VCC, ALL VERSIONS AND SPEEDS) Receiver Input to Output Delay Receiver Skew | tPLH - tPHL | Receiver Maximum Data Rate tPLH, tPHL tSKEW fMAX (Figure 4) (Figure 4) Full Full Full 20 50 3 40 90 10 ns ns Mbps
RECEIVER ENABLE/DISABLE CHARACTERISTICS (ALL MODES AND VERSIONS AND SPEEDS) Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable from Output Low Receiver Disable from Output High Receiver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High NOTES: 8. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified. 9. Supply current specification is valid for loaded drivers when DEN = 0V. 10. Applies to peak current. See "Typical Performance Curves" beginning on page 18 for more information. 11. RIN defaults to RS-485 mode (>15k) when the device is unpowered (VCC = 0V), or in SHDN, regardless of the state of the 485/232 pin. 12. VCC 5.25V. 13. The Slew pin has a pull-up resistor that enables only when in RS-485 mode (485/232 = VCC). 14. ON, RXEN, and DEN all simultaneously switched Low-to-High. 15. Parts are 100% tested at +25C. Over-temperature limits established by characterization and are not production tested. tZL tZH tLZ tHZ tZLSHDN CL = 15pF, SW = VCC (Figure 5) CL = 15pF, SW = GND (Figure 5) CL = 15pF, SW = VCC (Figure 5) CL = 15pF, SW = GND (Figure 5) CL = 15pF, SW = VCC (Figure 5) RS-485 Mode (Note 14) RS-232 Mode CL = 15pF, SW = GND (Figure 5) RS-485 Mode (Note 14) RS-232 Mode Full Full Full Full Full 25 Full 25 22 23 24 25 260 35 260 25 60 60 60 60 700 700 ns ns ns ns ns ns ns ns
tZHSHDN
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ISL81387, ISL41387 Test Circuits and Waveforms
R VCC DEN DY Y D Z R VOC RD VOD
+ -
VCM
FIGURE 1. RS-485 DRIVER VOD AND VOC TEST CIRCUIT
3V DY 1.5V 1.5V 0V tPLH OUT (Z) 50% tPHL VOH 50% VOL tPHL CL = 100pF Y D Z SIGNAL GENERATOR RDIFF CL = 100pF DIFF OUT (Z - Y) tR SKEW = |tPLH (Y OR Z) - tPHL (Z OR Y)| OUT (Y) tDLH 90% 10% 0V 50% tDHL 0V 90% 10% tF +VOD -VOD tPLH VOH 50% VOL DEN DY
VCC
FIGURE 2A. TEST CIRCUIT
FIGURE 2B. MEASUREMENT POINTS
FIGURE 2. RS-485 DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
DEN DY SIGNAL GENERATOR Y D Z CL 500 SW VCC GND ENABLED DEN 1.5V 1.5V 0V tZH tZH(SHDN) OUT (Y, Z) OUTPUT HIGH 2.3V tHZ VOH - 0.5V VOH 0V tZL tZL(SHDN) OUT (Y, Z) 2.3V OUTPUT LOW tLZ VCC VOL + 0.5V V OL 3V
FOR SHDN TESTS, SWITCH ON AND DEN L- H SIMULTANEOUSLY
PARAMETER OUTPUT tHZ tLZ tZH tZL tZH(SHDN) tZL(SHDN) Y/Z Y/Z Y/Z Y/Z Y/Z Y/Z
RXEN X X X X 0 0
DY 0/1 1/0 0/1 1/0 0/1 1/0
SW GND VCC GND VCC GND VCC
CL (pF) 15 15 100 100 100 100 FIGURE 3B. MEASUREMENT POINTS
FIGURE 3A. TEST CIRCUIT
FIGURE 3. RS-485 DRIVER ENABLE AND DISABLE TIMES
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ISL81387, ISL41387 Test Circuits and Waveforms (Continued)
VCC 0V RXEN A B R RA 15pF +1.5V B 0V tPLH 0V -1.5V tPHL VCC RA 1.5V 1.5V 0V
SIGNAL GENERATOR
FIGURE 4A. TEST CIRCUIT
FIGURE 4B. MEASUREMENT POINTS
FIGURE 4. RS-485 RECEIVER PROPAGATION DELAY
RXEN A R SIGNAL GENERATOR B RA 1k SW 15pF tZH(SHDN) FOR SHDN TESTS, SWITCH ON AND RXEN L- H SIMULTANEOUSLY RA tZL tZL(SHDN) RA 1.5V OUTPUT LOW tZH OUTPUT HIGH 1.5V tHZ VOH - 0.5V VOH 0V tLZ VCC VOL + 0.5V V
OL
VCC GND
ENABLED RXEN 1.5V 1.5V
3V 0V
PARAMETER tHZ tLZ tZH tZL tZH(SHDN) tZL(SHDN)
DEN X X X X 0 0
B +1.5V -1.5V +1.5V -1.5V +1.5V -1.5V
SW GND VCC GND VCC GND VCC FIGURE 5B. MEASUREMENT POINTS
FIGURE 5A. TEST CIRCUIT
FIGURE 5. RS-485 RECEIVER ENABLE AND DISABLE TIMES
DEN DY, Z Y, Z CL tDPHL RL OUT (Y, Z) SKEW = |tDPHL - tDPLH| 0V 0V VO3V DY,Z D 1.5V 1.5V 0V tDPLH VO+
VCC
SIGNAL GENERATOR
FIGURE 6A. TEST CIRCUIT
FIGURE 6B. MEASUREMENT POINTS
FIGURE 6. RS-232 DRIVER PROPAGATION DELAY
VCC
RXEN A, B RA, RB CL = 15pF
3V A, B R 1.3V 1.7V 0V tRPHL RA, RB SKEW = |tRPHL - tRPLH| tRPLH 2.4V 0.8V VOH VOL
SIGNAL GENERATOR
FIGURE 7A. TEST CIRCUIT
FIGURE 7B. MEASUREMENT POINTS
FIGURE 7. RS-232 RECEIVER PROPAGATION DELAY
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ISL81387, ISL41387 Detailed Description
The ISL81387, ISL41387 port supports dual protocols: RS-485, RS-422, and RS-232. RS-485 and RS-422 are differential (balanced) data transmission standards for use in high speed (up to 20Mbps) networks, or long haul and noisy environments. The differential signalling, coupled with RS-485's requirement for extended common mode range (CMR) of +12V to -7V make these transceivers extremely tolerant of ground potential differences, as well as voltages induced in the cable by external fields. Both of these effects are real concerns when communicating over the RS-485, RS-422 maximum distance of 4000' (1220m). It is important to note that the ISL81387, ISL41387 don't follow the RS-485 convention whereby the inverting I/O is labelled "B/Z", and the non-inverting I/O is "A/Y". Thus, in the following application diagrams, the 1387 A/Y (B/Z) pins connect to the B/Z (A/Y) pins of the generic RS-485, RS-422 ICs. RS-422 is typically a point-to-point (one driver talking to one receiver on a bus), or a point-to-multipoint (multidrop) standard that allows only one driver and up to 10 receivers on each bus. Because of the one driver per bus limitation, RS-422 networks use a two bus, full duplex structure for bidirectional communication, and the Rx inputs and Tx outputs (no tri-state required) connect to different busses, as shown in Figure 9. Tx and Rx enables aren't required, so connect RXEN and DEN to VCC through a 1k resistor. Conversely, RS-485 is a true multipoint standard, which allows up to 32 devices (any combination of drivers- must be tri-statable - and receivers) on each bus. Now bidirectional communication takes place on a single bus, so the Rx inputs and Tx outputs of a port connect to the same bus lines, as shown in Figure 8. A port set to RS-485, RS-422 mode includes one Rx and one Tx. RS-232 is a point-to-point, singled ended (signal voltages referenced to GND) communication protocol targeting fairly short (<150', 46m) and low data rate (<1Mbps) applications. A port contains two transceivers (2 Tx and 2 Rx) in RS-232 mode. Protocol selection is handled via the 485/232 logic pin.
GENERIC 1/2 DUPLEX 485 XCVR RO RE DE DI D 0.1F GND B/Z A/Y Y D Z GND B/Z A/Y RT RT GND D + GENERIC 1/2 DUPLEX 485 XCVR +5V + VCC R RO RE DE DI
+5V ISL81387, ISL41387 VCC RA RXEN * Tx/Rx DEN DY R B A + 0.1F
0.1F R +5V VCC
*QFN ONLY, CONNECT RXEN TO GND
FIGURE 8. TYPICAL HALF DUPLEX RS-485 NETWORK
GENERIC 422 Rx (SLAVE) RO RE GENERIC FULL DUPLEX 422 XCVR (SLAVE) +5V R 0.1F VCC D Z Y A R B GND RT +5V VCC GND B A RT A B Z Y GND D DI 0.1F + + +5V ISL81387 (MASTER) 1k DY DEN RXEN RA + 0.1F
VCC R RO
FIGURE 9. TYPICAL RS-422 NETWORK
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ISL81387, ISL41387 Advantages
These dual protocol ICs offer many parametric improvements versus those offered on competing dual protocol devices. Some of the major improvements are: * 15kV Bus Pin ESD - Eases board level requirements * 2.7V Diff VOUT - Better Noise immunity and/or distance * Full Failsafe RS-485 Rx - Eliminates bus biasing * Selectable RS-485 Data Rate - Up to 20Mbps, or slewrate limited for low EMI and fewer termination issues * High RS-232 Data Rate - >460kbps * Lower Tx and Rx Skews - Wider, consistent bit widths * Lower ICC - Max ICC is 2x to 4x lower than competition * Flow-Thru Pinouts - Tx, Rx bus pins on one side/logic pins on the other, for easy routing to connector/UART * Smaller (SSOP and QFN) and Pb-free packaging (see Tables 2 and 3, and "Low Power Shutdown (SHDN) Mode" on page 16), or when the 5V power supply is off. CHARGE PUMPS The on-chip charge pumps create the RS-232 transmitter power supplies (typically +6/-7V) from a single supply as low as 4.5V, and are enabled only if the port is configured for RS-232 operation, and not in SHDN. The efficient design requires only four small 0.1F capacitors for the voltage doubler and inverter functions. By operating discontinuously (i.e., turning off as soon as V+ and V- pump up to the nominal values), the charge pump contribution to RS-232 mode ICC is reduced significantly. Unlike competing devices that require the charge pump in RS-485 mode, disabling the charge pump saves power, and minimizes noise. If the application is a dedicated RS-485 port, then the charge pump capacitors aren't even required. DATA RATES AND CABLING Drivers operate at data rates up to 650kbps, and are guaranteed for data rates up to 460kbps. The charge pumps and drivers are designed such that one driver can be operated at the rated load, and at 460kbps (see Figure 33). Figure 33 also shows that drivers can easily drive several thousands of picofarads at data rates up to 250kbps, while still delivering compliant 5V output levels. Receivers operate at data rates up to 2Mbps. They are designed for a higher data rate to facilitate faster factory downloading of software into the final product, thereby improving the user's manufacturing throughput. Figures 36 and 37 illustrate driver and receiver waveforms at 250kbps, and 500kbps, respectively. For these graphs, one driver drives the specified capacitive load, and a receiver. RS-232 doesn't require anything special for cabling; just a single bus wire per transmitter and receiver, and another wire for GND. So an ISL81387, ISL41387 RS-232 port uses a five conductor cable for interconnection. Bus terminations are not required, nor allowed, by the RS-232 standard.
RS-232 Mode
RX FEATURES RS-232 receivers invert and convert RS-232 input levels (3V to 25V) to the standard TTL/CMOS levels required by a UART, ASIC, or controller serial port. Receivers are designed to operate at faster data rates than the drivers, and they feature very low skews (10ns) so the receivers contribute negligibly to bit width distortion. Inputs include the standard required 3k to 7k pull-down resistor, so unused inputs may be left unconnected. Rx inputs also have built-in hysteresis to increase noise immunity, and to decrease erroneous triggering due to slowly transitioning input signals. Rx outputs are short circuit protected, and are tri-statable via the active high RXEN pin, when the IC is shutdown (SHDN; see Tables 2 and 3, and "Low Power Shutdown (SHDN) Mode" on page 16), or via the active low RXEN pin available on the QFN package option (see"ISL41387 (QFN Package) Special Features" on page 17 for more details). TX FEATURES RS-232 drivers invert and convert the standard TTL/CMOS levels from a UART, or controller serial port to RS-232 compliant levels (5V minimum). The Tx delivers these compliant output levels even at data rates of 650kbps, and with loads of 1000pF. The drivers are designed for low skew (typically 12% of the 500kbps bit width), and are compliant to the RS-232 slew rate spec (4V/s to 30V/s) for a wide range of load capacitances. Tx inputs float if left unconnected, and may cause ICC increases. For the best results, connect unused inputs to GND. Tx outputs are short circuit protected, and incorporate a thermal SHDN feature to protect the IC in situations of severe power dissipation. See the RS-485 section for more details. Drivers tri-state via the active high DEN pin, in SHDN
RS-485 Mode
RX FEATURES RS-485 receivers convert differential input signals as small as 200mV, as required by the RS-485 and RS-422 standards, to TTL/CMOS output levels. The differential Rx provides maximum sensitivity, noise immunity, and common mode rejection. Per the RS-485 standard, receiver inputs function with common mode voltages as great as 7V outside the power supplies (i.e., +12V and -7V), making them ideal for long networks where induced voltages are a realistic concern. Each RS-485, RS-422 port includes a single receiver (RA), and the unused Rx output (RB) is disabled.
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Worst case receiver input currents are 20% lower than the 1 "unit load" (1mA) RS-485 limit, which translates to a 15k minimum input resistance. These receivers include a "full fail-safe" function that guarantees a high level receiver output if the receiver inputs are unconnected (floating), shorted together, or if the bus is terminated but undriven (i.e., differential voltage collapses to near zero due to termination). Failsafe with shorted, or terminated and undriven inputs is accomplished by setting the Rx upper switching point at -40mV, thereby ensuring that the Rx recognizes a 0V differential as a high level. All the Rx outputs are short circuit protected, and are tri-statable via the active high RXEN pin, or when the IC is shutdown (see Tables 2 and 3, and "Low Power Shutdown (SHDN) Mode" on page 16). ISL41387 (QFN) receiver outputs are also tri-statable via an active low RXEN input (see "ISL41387 (QFN Package) Special Features" on page 17 for more details). For the ISL41387 (QFN), when using the active high RXEN function, the RXEN pin may be left floating (internally pulled high), or should be connected to VCC through a 1k resistor. If using the active low RXEN, then the RXEN pin must be connected to GND. TX FEATURES The RS-485, RS-422 driver is a differential output device that delivers at least 2.2V across a 54 load (RS-485), and at least 2.5V across a 100 load (RS-422). Both levels significantly exceed the standards requirements, and these exceptional output voltages increase system noise immunity, and/or allow for transmission over longer distances. The drivers feature low propagation delay skew to maximize bit widths, and to minimize EMI. To allow multiple drivers on a bus, the RS-485 specification requires that drivers survive worst case bus contentions undamaged. The ISL81387, ISL41387 drivers meet this requirement via driver output short circuit current limits, and on-chip thermal shutdown circuitry. The output stages incorporate current limiting circuitry that ensures that the output current never exceeds the RS-485 specification, even at the common mode voltage range extremes. In the event of a major short circuit condition, devices also include a thermal shutdown feature that disables the drivers whenever the die temperature becomes excessive. This eliminates the power dissipation, allowing the die to cool. The drivers automatically re-enable after the die temperature drops about 15. If the contention persists, the thermal shutdown/re-enable cycle repeats until the fault is cleared. Receivers stay operational during thermal shutdown. RS-485 multi-driver operation also requires drivers to include tri-state functionality, so the port has a DEN pin to control this function. If the driver is used in an RS-422 network, such that driver tri-state isn't required, then the DEN pin should connect to VCC through a 1k resistor. Drivers are also tri-stated when the IC is in SHDN, or when the 5V power supply is off. SPEED OPTIONS The ISL81387 (SOIC/SSOP) features two speed options that are user selectable via the SLEW pin: a high slew rate setting optimized for 20Mbps data rates (Fast), and a slew rate limited option for operation up to 460kbps (Med). The ISL41387 (QFN) offers an additional, more slew rate limited, option for data rates up to 115kbps (Slow). See "Data Rate, Cables and Terminations" on page 15 and "RS-485 Slew Rate Limited Data Rates" on page 17 for more information. Receiver performance is the same for all three speed options. DATA RATE, CABLES AND TERMINATIONS RS-485, RS-422 are intended for network lengths up to 4000' (1220m), but the maximum system data rate decreases as the transmission length increases. Devices operating at the maximum data rate of 20Mbps are limited to lengths of 20' to 30' (6m to 9m), while devices operating at or below 115kbps can operate at the maximum length of 4000' (1220m). Higher data rates require faster edges, so both the ISL81387, ISL41387 versions offer an edge rate capable of 20Mbps data rates. They both have a second option for 460kbps, but the ISL41387 also offers another, very slew rate limited, edge rate to minimize problems at slow data rates. Nevertheless, for the best jitter performance when driving long cables, the faster speed settings may be preferable, even at low data rates. See "RS-485 Slew Rate Limited Data Rates" on page 17 for details. Twisted pair is the cable of choice for RS-485, RS-422 networks. Twisted pair cables tend to pick up noise and other electromagnetically induced voltages as common mode signals, which are effectively rejected by the differential receivers in these ICs. The preferred cable connection technique is "daisy-chaining", where the cable runs from the connector of one device directly to the connector of the next device, such that cable stub lengths are negligible. A "backbone" structure, where stubs run from the main backbone cable to each device's connector, is the next best choice, but care must be taken to ensure that each stub is electrically "short". See Table 4 for recommended maximum stub lengths for each speed option.
TABLE 4. RECOMMENDED STUB LENGTHS SPEED OPTION SLOW MED FAST MAXIMUM STUB LENGTH ft (m) 350 to 500 (107 to 152) 100 to 150 (30.5 to 46) 1 to 3 (0.3 to 0.9)
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Proper termination is imperative to minimize reflections when using the 20Mbps speed option. Short networks using the medium and slow speed options need not be terminated, but terminations are recommended unless power dissipation is an overriding concern. Note that the RS-485 specification allows a maximum of two terminations on a network, otherwise the Tx output voltage may not meet the required VOD. In point-to-point, or point-to-multipoint (RS-422) networks, the main cable should be terminated in its characteristic impedance (typically 120) at the end farthest from the driver. In multi-receiver applications, stubs connecting receivers to the main cable should be kept as short as possible, but definitely shorter than the limits shown in Table 4. Multipoint (RS-485) systems require that the main cable be terminated in its characteristic impedance at both ends. Again, keep stubs connecting a transceiver to the main cable as short as possible, and refer to Table 4. Avoid "star", and other configurations, where there are many "ends" which would require more than the two allowed terminations to prevent reflections.
Low Power Shutdown (SHDN) Mode
The ISL81387, ISL41387 enter the SHDN mode when ON = 0, and the Tx and Rx are disabled (DEN = 0, RXEN = 0, and RXEN = 1), and the already low supply current drops to as low as 5A. SHDN disables the Tx and Rx outputs, and disables the charge pumps if the port is in RS-232 mode, so V+ collapses to VCC, and V- collapses to GND. All but 5A of SHDN ICC current is due to control input (SPB, SLEW) pull-up resistors (~20A/resistor), so SHDN ICC varies depending on the ISL81387, ISL41387 configuration. The specification tables indicate the worst case values, but careful selection of the configuration yields lower currents. For example, in RS-232 mode the SPB pin isn't used, so floating it or tying it high minimizes SHDN ICC.
ISL81387
CONNECTOR
A B Y Z
R D
RA DY UART OR ASIC OR CONTROLLER
High ESD
All pins on the ISL81387, ISL41387 include ESD protection structures rated at 4kV (HBM), which is good enough to survive ESD events commonly seen during manufacturing. But the bus pins (Tx outputs and Rx inputs) are particularly vulnerable to ESD events because they connect to an exposed port on the exterior of the finished product. Simply touching the port pins, or connecting a cable, can destroy an unprotected port. ISL81387, ISL41387 bus pins are fitted with advanced structures that deliver ESD protection in excess of 15kV (HBM), without interfering with any signal in the RS-485 or the RS-232 range. This high level of protection may eliminate the need for board level protection, or at the very least will increase the robustness of any board level scheme.
FIGURE 10. ILLUSTRATION OF FLOW THROUGH PINOUT
On the ISL41387, the SHDN ICC increases as VL decreases. VL powers each control pin input stage and sets its VOH at VL rather than VCC. VCC powers the second stage, but the second stage input isn't driven to the rail, so some ICC current flows. See Figure 20 for details. When enabling from SHDN in RS-232 mode, allow at least 20s for the charge pumps to stabilize before transmitting data. If fast enables are required, and ICC isn't the greatest concern, disable the drivers with the DEN pin to keep the charge pumps active. The charge pumps aren't used in RS-485 mode, so the transceiver is ready to send or receive data in less than 1s, which is much faster than competing devices that require the charge pump for all modes of operation.
Small Packages
Many competing dual protocol ICs are available only in monstrously large 24 to 28 Ld SOIC packages. The ISL81387's 20 Ld SSOP is more than 50% smaller than even a 24 Ld SOIC, and the ISL41387's tiny 6mmx6mm QFN is 80% smaller than a 28 Ld SOIC.
Internal Loopback Mode
Setting ON = 0, DEN = 1, and RXEN = 1 or RXEN = 0 (QFN only), places the port in the loopback mode, a mode that facilitates implementing board level self test functions. In loopback, internal switches disconnect the Rx inputs from the Rx outputs, and feed back the Tx outputs to the appropriate Rx output. This way the data driven at the Tx input appears at the corresponding Rx output (refer to "Typical Operating Circuit" on page 6). The Tx outputs remain connected to their terminals, so the external loads are reflected in the loopback performance. This allows the loopback function to potentially detect some common bus faults such as one or both driver outputs shorted to GND, or outputs shorted together.
Flow Through Pinouts
Even the ISL81387, ISL41387 pinouts are features, in that the "flow-through" design simplifies board layout. Having the bus pins all on one side of the package for easy routing to a cable connector, and the Rx outputs and Tx inputs on the other side for easy connection to a UART, avoids costly and problematic crossovers. Figure 10 illustrates the flow-through nature of the pinout.
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Note that the loopback mode uses an additional set of receivers, as shown in "Typical Operating Circuit" on page 6. These loopback receivers are not standards compliant, so the loopback mode can't be used to implement a half-duplex RS-485 transceiver. VL can be anywhere from VCC down to 1.65V, but the input switching points may not provide enough noise margin when VL < 1.8V. Table 5 indicates typical VIH and VIL values for various VL values so the user can ascertain whether or not a particular VL voltage meets his or her needs.
TABLE 5. VIH AND VIL vs VL FOR VCC = 5V VL (V) 1.65V 1.8V 2.0V 2.5V 3.3V VIH (V) 0.79 0.82 0.87 0.99 1.19 VIL (V) 0.50 0.60 0.69 0.86 1.05
ISL41387 (QFN Package) Special Features
Logic Supply (VL Pin)
The ISL41387 (QFN) includes a VL pin that powers the logic inputs (Tx inputs and control pins) and Rx outputs. These pins interface with "logic" devices such as UARTs, ASICs, and controllers, and today most of these devices use power supplies significantly lower than 5V. Thus, a 5V output level from a 5V powered dual protocol IC might seriously overdrive and damage the logic device input. Similarly, the the logic device's low VOH might not exceed the VIH of a 5V powered dual protocol input. Connecting the VL pin to the power supply of the logic device (as shown in Figure 11) limits the ISL41387's Rx output VOH to VL (see Figure 14), and reduces the Tx and control input switching points to values compatible with the logic device output levels. Tailoring the logic pin input switching points and output levels to the supply voltage of the UART, ASIC, or controller eliminates the need for a level shifter/translator between the two ICs.
VCC = +5V VCC = +2V
The VL supply current (IL) is typically less than 60A, as shown in Figures 19 and 20. All of the DC VL current is due to inputs with internal pull-up resistors (SPB, SLEW, RXEN) being driven to the low input state. The worst case IL current occurs when all three of the inputs are low (see Figure 19), due to the IL through the pull-up resistors. IIL through an input pull-up resistor is ~20A, so the IL in Figure 19 drops by about 40A (at VL = 5V) when the SPB is high and 232 mode disables the SLEW pin pull-up (middle vs top curve). When all three inputs are driven high, IL drops to ~10nA, so to minimize power dissipation drive these inputs high when unneeded (e.g., SPB isn't used in RS-232 mode, so drive it high).
RA
VOH = 5V
RXD
ESD DIODE
Active Low Rx Enable (RXEN)
In many RS-485 applications, especially half duplex configurations, users like to accomplish "echo cancellation" by disabling the corresponding receiver while its driver is transmitting data. This function is available on the QFN package via an active low RXEN pin. The active low function also simplifies direction control, by allowing a single Tx/Rx direction control line. If the active high RXEN were used, either two valuable I/O pins would be used for direction control, or an external inverter is required between DEN and RXEN. Figure 12 details the advantage of using the RXEN pin. When using RXEN, ensure that RXEN is tied to GND.
DY GND
VIH 2V VOH 2V
TXD GND
ISL81387 VCC = +5V
UART/PROCESSOR VCC = +2V
VL RA VOH = 2V RXD
RS-485 Slew Rate Limited Data Rates
ESD DIODE
DY GND
VIH = 0.9V VOH 2V
TXD GND
ISL41387
UART/PROCESSOR
FIGURE 11. USING VL PIN TO ADJUST LOGIC LEVELS
The ISL81387, ISL41387 FAST speed option (SLEW = High) utilizes Tx output transitions optimized for a 20Mbps data rate. These fast edges may increase EMI and reflection issues, even though fast transitions aren't required at the lower data rates used by many applications. With the SLEW pin low, both product types switch to a moderately slew rate limited output transition targeted for 460kbps (MED) data rates. The ISL41387 (QFN version) offers an additional, slew rate limited data rate that is optimized for 115kbps (SLOW), and is selected when SLEW = 0 and SPB = 0 (see Table 3). The slew limited edges permit longer unterminated networks, or longer stubs off terminated busses, and help
17
FN6201.3 November 21, 2007
ISL81387, ISL41387
minimize EMI and reflections. Nevertheless, for the best jitter performance when driving long cables, the faster speed options may be preferable, even at lower data rates. The faster output transitions deliver less variability (jitter) when loaded with the large capacitance associated with long cables. Figures 42, 43, and 44 detail the jitter performance of the three speed options while driving three different cable lengths. The figures show that under all conditions the faster the edge rate, the better the jitter performance. Of course, faster transitions require more attention to ensuring short stub lengths, and quality terminations, so there are trade-offs to be made. Assuming a jitter budget of 10%, it is likely better to go with the slow speed option for data rates of 115kbps or less, to minimize fast edge effects. Likewise, the medium speed option is a good choice for data rates between 115kbps and 460kbps. For higher data rates, or when the absolute best jitter is required, use the high speed option.
1k OR NC RXEN * RA Tx/Rx RXEN DEN DY D R ISL41387 +5V + VCC B A Y Z GND ACTIVE HIGH RX ENABLE ISL41387 +5V + RXEN RA RXEN * Tx/Rx DEN DY D Y Z GND * QFN ONLY ACTIVE LOW RX ENABLE R VCC B A 0.1F 0.1F
Evaluation Board
An evaluation board, part number ISL41387EVAL1, is available to assist in assessing the dual protocol IC's performance. The evaluation board contains a QFN packaged device, but because the same die is used in all packages, the board is also useful for evaluating the functionality of the other versions. The board's design allows for evaluation of all standard features, plus the QFN specific features. Refer to the evaluation board application note for details and contact your sales rep for ordering information.
FIGURE 12. USING ACTIVE LOW vs ACTIVE HIGH RX ENABLE
Typical Performance Curves
50 RECEIVER OUTPUT CURRENT (mA)
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified.
5 VOL, +25C HIGH OUTPUT VOLTAGE (V)
40 VOL, +85C 30
4
3 IOH = -1mA 2 IOH = -8mA 1 IOH = -4mA
20
VOH, +25C VOH, +85C
10
0
0 0 1 2 3 4 RECEIVER OUTPUT VOLTAGE (V) 5 0 1 2 VL (V) 3 4 5
FIGURE 13. RECEIVER OUTPUT CURRENT vs RECEIVER OUTPUT VOLTAGE
FIGURE 14. RECEIVER HIGH OUTPUT VOLTAGE vs LOGIC SUPPLY VOLTAGE (VL)
18
FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Performance Curves
100 DRIVER OUTPUT CURRENT (mA) 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 DIFFERENTIAL OUTPUT VOLTAGE (V) 5 DIFFERENTIAL OUTPUT VOLTAGE (V)
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified. (Continued)
3.6 3.5 RDIFF = 100 3.4 3.3 3.2 3.1 3.0 -40 RDIFF = 54
-25
0
25
50
75
85
TEMPERATURE (C)
FIGURE 15. RS-485, DRIVER OUTPUT CURRENT vs DIFFERENTIAL OUTPUT VOLTAGE
FIGURE 16. RS-485, DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs TEMPERATURE
150 100 50 ICC (mA) 0 -50 -100 -40C -150 -7 -6 -4 -2 0 2 4 6 OUTPUT VOLTAGE (V) 8 10 12 Y OR Z = HIGH +85C +25C Y OR Z = LOW FULL TEMP RANGE
4.0 RS-232, RXEN, RXEN, ON = X, DEN = VCC 3.5 RS-232, RXEN, RXEN = X, ON = VCC, DEN = GND 3.0 2.5 2.0 RS-485, HALF DUPLEX, DEN = VCC, RXEN, RXEN, ON = X 1.5 1.0 -40 RS-485, FULL DUPLEX, DEN = VCC, RXEN, RXEN, ON = X RS-485, DEN = GND, RXEN, RXEN = X, ON = VCC -25 0 25 50 75 85 TEMPERATURE (C)
FIGURE 17. RS-485, DRIVER OUTPUT CURRENT vs SHORT CIRCUIT VOLTAGE
OUTPUT CURRENT (mA)
FIGURE 18. SUPPLY CURRENT vs TEMPERATURE
10m 1m 100 IL (A) 10 1 100n 10n 1n 2
NO LOAD VIN = VL or GND DEN, RXEN, ON = GND
500 VL VCC VL > VCC 400 ICC AND IL (mA) DEN, RXEN, DY, DZ/SLEW, ON = GND NO LOAD VIN = VL OR GND RXEN = VL RS-232/RS-485 ICC
RS-485, SLEW, SPB, RXEN = GND RS-232, RXEN = GND, SPB = VL
300
200
RS-232, SPB, RXEN = VL OR RS-485, SLEW, SPB, RXEN = VL 3 4 VL (V) 5 6
100
SPB = VL RS-232 IL
SPB = GND RS-485 IL 3.0 3.5 VL (V) 4.0 4.5 5.0
0 2.0
2.5
FIGURE 19. RS-232, VL SUPPLY CURRENT vs VL VOLTAGE (QFN ONLY)
FIGURE 20. VCC AND VL SHDN SUPPLY CURRENTS vs VL VOLTAGE (QFN ONLY)
19
FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Performance Curves
1700 RDIFF = 54, CL = 100pF
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified. (Continued)
400 350 |tPHLZ - tPLHY| 300 |tPLHZ - tPHLY| RDIFF = 54, CL = 100pF
1650 PROPAGATION DELAY (ns)
1600 tDHL tDLH SKEW (ns) 250 200 150 100 50 1400 -40
1550
1500 tDHL 1450
|tDLH - tDHL|
-25
0
25
50
75
85
-40
-25
0
25
50
75
85
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 21. RS-485, DRIVER PROPAGATION DELAY vs TEMPERATURE (SLOW DATA RATE, QFN ONLY)
560 RDIFF = 54, CL = 100pF 550
FIGURE 22. RS-485, DRIVER SKEW vs TEMPERATURE (SLOW DATA RATE, QFN ONLY)
120
RDIFF = 54, CL = 100pF |tPHLZ - tPLHY|
100 PROPAGATION DELAY (ns) 540 530 520 tDHL 510 tDLH 500 490 480 470 -40 tDHL 20 SKEW (ns) 80
60 |tPLHZ - tPHLY| 40
|tDLH - tDHL| -25 0 25 50 75 85 0 -40 -25 0 25 TEMPERATURE (C) 50 75 85
TEMPERATURE (C)
FIGURE 23. RS-485, DRIVER PROPAGATION DELAY vs TEMPERATURE (MEDIUM DATA RATE, QFN ONLY)
40
FIGURE 24. RS-485, DRIVER SKEW vs TEMPERATURE (MEDIUM DATA RATE, QFN ONLY)
RDIFF = 54, CL = 100pF
2.5
RDIFF = 54, CL = 100pF
PROPAGATION DELAY (ns)
2.0 35 |tDLH - tDHL| tDHL 30 tDLH 25 0.5 |tPHLZ - tPLHY| 0 -40 -25 SKEW (ns) 1.5
1.0 |tPLHZ - tPHLY|
20 -40
-25
0
25
50
75
85
0
25
50
75
85
TEMPERATURE (C)
TEMPERATURE (C)
FIGURE 25. RS-485, DRIVER PROPAGATION DELAY vs TEMPERATURE (FAST DATA RATE)
FIGURE 26. RS-485, DRIVER SKEW vs TEMPERATURE (FAST DATA RATE)
20
FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Performance Curves
RECEIVER OUTPUT (V) DY 5 0
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified. (Continued)
DRIVER INPUT (V) RECEIVER OUTPUT (V) RDIFF = 60, CL = 100pF DY 5 0 DRIVER INPUT (V) DRIVER INPUT (V) DRIVER INPUT (V)
RDIFF = 60, CL = 100pF
5 0
5 0
RA
RA
DRIVER OUTPUT (V)
4 3 2 1 0
DRIVER OUTPUT (V)
5 Y Z
5 4 3 2 1 0 TIME (400ns/DIV) Y Z
TIME (400ns/DIV)
FIGURE 27. RS-485, DRIVER AND RECEIVER WAVEFORMS, LOW TO HIGH (SLOW DATA RATE, QFN ONLY)
FIGURE 28. RS-485, DRIVER AND RECEIVER WAVEFORMS, HIGH TO LOW (SLOW DATA RATE, QFN ONLY)
RECEIVER OUTPUT (V)
DRIVER INPUT (V)
RDIFF = 60, CL = 100pF DY 5 0
RECEIVER OUTPUT (V)
5 0
RDIFF = 60, CL = 100pF DY 5 0
5 0
RA
RA
DRIVER OUTPUT (V)
4 3 2 1 0
DRIVER OUTPUT (V)
5 Y Z
5 4 3 2 1 0 TIME (200ns/DIV) Z
Y
TIME (200ns/DIV)
FIGURE 29. RS-485, DRIVER AND RECEIVER WAVEFORMS, LOW TO HIGH (MEDIUM DATA RATE, QFN ONLY)
FIGURE 30. RS-485, DRIVER AND RECEIVER WAVEFORMS, HIGH TO LOW (MEDIUM DATA RATE, QFN ONLY)
DRIVER INPUT (V)
RECEIVER OUTPUT (V)
RECEIVER OUTPUT (V)
RDIFF = 60, CL = 100pF DY 5 0
5 0
RDIFF = 60, CL = 100pF DY 5 0
5 0
RA
RA
DRIVER OUTPUT (V)
DRIVER OUTPUT (V)
5 4 3 2 1 0 TIME (10ns/DIV) Z Y
5 4 3 2 1 0 TIME (10ns/DIV) Y Z
FIGURE 31. RS-485, DRIVER AND RECEIVER WAVEFORMS, LOW TO HIGH (FAST DATA RATE)
FIGURE 32. RS-485, DRIVER AND RECEIVER WAVEFORMS, HIGH TO LOW (FAST DATA RATE)
21
FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Performance Curves
7.5 TRANSMITTER OUTPUT VOLTAGE (V) 250kbps RS-232 REGION OF NONCOMPLIANCE TRANSMITTER OUTPUT VOLTAGE (V) 5.0 2.5 ALL TOUTS LOADED WITH 3k TO GND 0 -2.5 -5.0 -7.5 1 TRANSMITTER AT 250kbps OR 500kbps, OTHER TRANSMITTER AT 30kbps 500kbps VOUT+ 5.0 VOUT+
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified. (Continued)
7.5
2.5 OUTPUTS STATIC ALL TOUTS LOADED WITH 3k TO GND
0
-2.5
500kbps VOUT 250kbps 0 1000 2000 3000 4000 5000
-5.0 -7.5 -40
VOUT -25 0 25 TEMPERATURE (C) 50 75 85
LOAD CAPACITANCE (pF)
FIGURE 33. RS-232, TRANSMITTER OUTPUT VOLTAGE vs LOAD CAPACITANCE
FIGURE 34. RS-232, TRANSMITTER OUTPUT VOLTAGE vs TEMPERATURE
40 TRANSMITTER OUTPUT CURRENT (mA) CL = 3500pF, 1 CHANNEL SWITCHING 30 Y or Z = LOW 20 10 VOUT SHORTED TO GND 0 -10 -20 -30 -40 -40 -25 Y or Z = HIGH 0 0 25 TEMPERATURE (C) 50 75 85 0 Y/A -5 5 RA 5 DY 0 5
2s/DIV
FIGURE 35. RS-232, TRANSMITTER SHORT CIRCUIT CURRENT vs TEMPERATURE
FIGURE 36. RS-232, TRANSMITTER AND RECEIVER WAVEFORMS AT 250kbps
60 CL = 1000pF, 1 CHANNEL SWITCHING 5 DY 0 5 0 Y/A -5 5 RA 0 RECEIVER + DUTY CYCLE (%) 58
VIN = 5V FULL TEMP RANGE
56
54 SR IN = 15V/s 52 SR IN = 100V/s 50
48 1s/DIV. 50 500 1000 DATA RATE (kbps) 1500 2000
FIGURE 37. RS-232, TRANSMITTER AND RECEIVER WAVEFORMS AT 500kbps
FIGURE 38. RS-232, RECEIVER OUTPUT +DUTY CYCLE vs DATA RATE
22
FN6201.3 November 21, 2007
ISL81387, ISL41387 Typical Performance Curves
1100 1000 900 DATA RATE (kbps) 800 700 600 500 400 300 200 100 100 1000 2000 3000 LOAD CAPACITANCE (pF) 4000 5000 1 TRANSMITTER AT +85C 2 TRANSMITTERS AT +85C 2 TRANSMITTERS AT +25C 1 TRANSMITTER AT +25C
VCC = VL = 5V, TA = +25C; Unless Otherwise Specified. (Continued)
VOUT 4V 7.5 TRANSMITTER OUTPUT VOLTAGE (V) RS-232 REGION OF NONCOMPLIANCE
ALL TOUTS LOADED WITH 5k TO GND
5.0 2.5
VOUT+ +85C
+25C
2 TRANSMITTERS SWITCHING 0 ALL TOUTS LOADED WITH 5k TO GND, CL = 1000pF -2.5 +85C VOUT -7.5 0 100 200 300 400 500 600 700 800 DATA RATE (kbps) +25C
-5.0
FIGURE 39. RS-232, TRANSMITTER MAXIMUM DATA RATE vs LOAD CAPACITANCE
FIGURE 40. RS-232, TRANSMITTER OUTPUT VOLTAGE vs DATA RATE
450 2 TRANSMITTERS SWITCHING 400 350 SKEW (ns) +85C 300 250 +25C 200 150 50 JITTER (%) ALL TOUTS LOADED WITH 3k TO GND, CL = 1000pF
100
SLOW 10
MED FAST
1
0.1 150 250 350 450 550 650 750 32 100 200 300 400 DATA RATE (kbps)
DOUBLE TERM'ED WITH 121 500 600 700 800 900 1000
DATA RATE (kbps)
FIGURE 41. RS-232, TRANSMITTER SKEW vs DATA RATE
FIGURE 42. RS-485, TRANSMITTER JITTER vs DATA RATE WITH 2000' CAT-5 CABLE
100 SLOW 10 JITTER (%) FAST JITTER (%) MED
100 SLOW
MED
10
FAST 1
1
0.1 32 100 200 300 400
DOUBLE TERM'ED WITH 121 500 600 700 800 900 1000
0.1 32 100 200 300 400
DOUBLE TERM'ED WITH 121 500 600 700 800 900 1000
DATA RATE (kbps)
DATA RATE (kbps)
FIGURE 43. RS-485, TRANSMITTER JITTER vs DATA RATE WITH 1000' CAT-5 CABLE
FIGURE 44. RS-485, TRANSMITTER JITTER vs DATA RATE WITH 350' CAT-5 CABLE
23
FN6201.3 November 21, 2007
ISL81387, ISL41387 Die Characteristics
SUBSTRATE AND QFN THERMAL PAD POTENTIAL (POWERED UP): GND TRANSISTOR COUNT: 2490 PROCESS: BiCMOS
24
FN6201.3 November 21, 2007
ISL81387, ISL41387
Package Outline Drawing
L40.6x6
40 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE Rev 3, 10/06
4X 4.5 6.00 A B 6 PIN 1 INDEX AREA 31 30 36X 0.50 40 1 6 PIN #1 INDEX AREA
4 . 10 0 . 15 6.00
21 (4X) 0.15 20 TOP VIEW 40X 0 . 4 0 . 1 BOTTOM VIEW 11
10
0.10 M C A B 4 0 . 23 +0 . 07 / -0 . 05
SEE DETAIL "X" 0.10 C BASE PLANE SIDE VIEW ( 36X 0 . 5 ) SEATING PLANE 0.08 C C
0 . 90 0 . 1 ( 5 . 8 TYP ) ( 4 . 10 )
C ( 40X 0 . 23 ) ( 40X 0 . 6 ) TYPICAL RECOMMENDED LAND PATTERN
0 . 2 REF
5
0 . 00 MIN. 0 . 05 MAX. DETAIL "X"
NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal 0.05 4. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be either a mold or mark feature.
25
FN6201.3 November 21, 2007
ISL81387, ISL41387 Small Outline Plastic Packages (SOIC)
N INDEX AREA E -BH 0.25(0.010) M BM
M20.3 (JEDEC MS-013-AC ISSUE C) 20 LEAD WIDE BODY SMALL OUTLINE PLASTIC PACKAGE
INCHES SYMBOL A MIN 0.0926 0.0040 0.014 0.0091 0.4961 0.2914 MAX 0.1043 0.0118 0.019 0.0125 0.5118 0.2992 MILLIMETERS MIN 2.35 0.10 0.35 0.23 12.60 7.40 MAX 2.65 0.30 0.49 0.32 13.00 7.60 NOTES 9 3 4 5 6 7 8 Rev. 2 6/05
1
2
3
A1
L SEATING PLANE
B C
h x 45
-A-
D -C-
A
D E
A1 0.10(0.004) C
e H h L N
0.050 BSC 0.394 0.010 0.016 20 0 8 0.419 0.029 0.050
1.27 BSC 10.00 0.25 0.40 20 0 10.65 0.75 1.27
e
B 0.25(0.010) M C AM BS
NOTES: 1. Symbols are defined in the "MO Series Symbol List" in Section 2.2 of Publication Number 95. 2. Dimensioning and tolerancing per ANSI Y14.5M-1982. 3. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. Dimension "E" does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 6. "L" is the length of terminal for soldering to a substrate. 7. "N" is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. The lead width "B", as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch) 10. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact.
26
FN6201.3 November 21, 2007
ISL81387, ISL41387 Shrink Small Outline Plastic Packages (SSOP)
N INDEX AREA E -B1 2 3 0.25 0.010 L GAUGE PLANE H 0.25(0.010) M BM
M20.209 (JEDEC MO-150-AE ISSUE B)
20 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE INCHES SYMBOL A A1
SEATING PLANE
MILLIMETERS MIN 1.73 0.05 1.68 0.25 0.09 7.07 5.20' 7.65 0.63 20 MAX 1.99 0.21 1.78 0.38 0.20' 7.33 5.38 7.90' 0.95 6 7 8 deg. Rev. 3 11/02 3 4 9 NOTES
MIN 0.068 0.002 0.066 0.010' 0.004 0.278 0.205 0.301 0.025 20 0 deg.
MAX 0.078 0.008' 0.070' 0.015 0.008 0.289 0.212 0.311 0.037
A2 B C D
-A-
D -C-
A
A1 0.10(0.004) A2 C
E e H L N
e
B 0.25(0.010) M C AM BS
0.026 BSC
0.65 BSC
NOTES: 1. Symbols are defined in the "MO Series Symbol List" in Section 2.2 of Publication Number 95. 2. Dimensioning and tolerancing per ANSI Y14.5M-1982. 3. Dimension "D" does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.20mm (0.0078 inch) per side. 4. Dimension "E" does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.20mm (0.0078 inch) per side. 5. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 6. "L" is the length of terminal for soldering to a substrate. 7. "N" is the number of terminal positions. 8. Terminal numbers are shown for reference only. 9. Dimension "B" does not include dambar protrusion. Allowable dambar protrusion shall be 0.13mm (0.005 inch) total in excess of "B" dimension at maximum material condition. 10. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact.
8 deg.
0 deg.
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com 27
FN6201.3 November 21, 2007

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