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74ACT245
OCTAL BUS TRANSCEIVER (3-STATE)
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HIGH SPEED: tPD = 5.5 ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 8 A (MAX.) at TA = 25 oC COMPATIBLE WITH TTL OUTPUTS VIH = 2V (MIN) VIL = 0.8V (MAX) 50 TRANSMISSION LINE OUTPUT DRIVE CAPABILITY SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 24 mA (MIN) BALANCED PROPAGATION DELAYS: tPLH tPHL OPERATING VOLTAGE RANGE: VCC (OPR) = 4.5V to 5.5V PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 245 IMPROVED LATCH-UP IMMUNITY
M (Micro Package) B (Plastic Package) ORDER CODES : 74ACT245B 74ACT245M 74ACT245T T (TSSOP Package)
DESCRIPTION The ACT245 is an advanced CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS technology. It is ideal for low power applications mantaining high speed operation similar to equivalent Bipolar Schottky TTL. This IC is intended for two-way asynchronous communication between data buses and the PIN CONNECTION AND IEC LOGIC SYMBOLS
direction of data trasmission is determined by DIR input. The enable input G can be used to disable the device so that the buses are effectively isolated. All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage. IT IS PROHIBITED TO APPLY A SIGNAL TO A TERMINAL WHEN IT IS IN OUTPUT MODE AND WHEN A BUS THERMINAL IS FLOATING (HIGH IMPEDANCE STATE) IT IS REQUESTED TO FIX THE INPUT LEVEL BY MEANS OF EXTERNAL PULL DOWN OR PULL UP RESISTOR.
May 1999
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74ACT245
INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION
PIN No 1 2,3, 4,5, 6, 7,8, 9 18, 17, 16, 15, 14, 13, 12, 11 19 10 20 SYMBOL DIR A1 to A8 B1 to B8 NAME AND FUNCT ION Directional Control Data Inputs/Outputs Data Inputs/Outputs
G GND VCC
Output Enabel Input Ground (0V) Positive Supply Voltage
TRUTH TABLE
INPUT G L L H
X:"H" or "L" Z: High impedance
F UNCTION DIR L H X A BUS OUTPUT INPUT Z B BUS INPUT OUTPUT Z
OUT PUT A =B B =A Z
ABSOLUTE MAXIMUM RATINGS
Symbol VCC VI VO IIK IOK IO ICC orIGND Tstg TL Supply Voltage DC Input Voltage DC Output Voltage DC Input Diode Current DC Output Diode Current DC Output Current DC VCC or Ground Current Storage Temperature Lead Temperature (10 sec) Parameter Value -0.5 to +7 -0.5 to VCC + 0.5 -0.5 to VCC + 0.5 20 20 50 400 -65 to +150 300 Unit V V V mA mA mA mA
o o
C C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol VCC VI VO Top dt/dv Supply Voltage Input Voltage Output Voltage Operating Temperature: Input Rise and Fall Time VCC = 4.5 to 5.5V (note 1) Parameter Value 4.5 to 5.5 0 to VCC 0 to VCC -40 to +85 8 Unit V V V
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C
ns/V
1) VIN from 0.8 V to 2.0 V
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74ACT245
DC SPECIFICATIONS
Symb ol Parameter V CC (V) VIH VIL VOH High Level Input Voltage Low Level Input Voltage High Level Output Voltage 4.5 5.5 4.5 5.5 4.5 5.5 4.5 5.5 VOL Low Level Output Voltage 4.5 5.5 4.5 5.5 II IOZ ICCT ICC IOLD IOHD Input Leakage Current 3 State Output Leakage Current Max ICC /Input Quiescent Supply Current Dynamic Output Current (note 1, 2) 5.5 5.5 5.5 5.5 5.5 VI = VIH or VIL
(*)
Test Co nditions Min. VO = 0.1 V or VCC - 0.1 V VO = 0.1 V or VCC - 0.1 V VI(*) = VIH or VIL IO=-50 A IO=-50 A IO=-24 mA IO=-24 mA IO=50 A IO=50 A IO=24 mA IO=24 mA VI = VCC orGND VI = VIH orVIL VO = VCC orGND VI = VCC -2.1V VI = VCC orGND VOLD = 1.65 V max VOHD = 3.85 V min 0.6 4.4 5.4 3.86 4.86 0.001 0.001 2.0 2.0 T yp. 1.5 1.5 1.5 1.5 4.49 5.49
Valu e T A = 25 oC Max. -40 to 85 o C Min. 2.0 2.0 0.8 0.8 4.4 5.4 3.76 4.76 0.1 0.1 0.36 0.36 0.1 0.5 0.1 0.1 0.44 0.44 1 5 1.5 8 80 75 -75 0.8 0.8 Max.
Un it
V V
V
V
A A mA A mA mA
1) Maximum test duration 2ms, one output loaded attime 2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50 . (*) All outputs loaded.
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74ACT245
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 , Input tr = tf =3 ns)
Symb ol Parameter V CC (V) tPLH tPHL tPZL tPZH tPLZ tPHZ Propagation Delay Time Output Enable Time Output Disable Time 5.0(*) 5.0 5.0
(*)
T est Con ditio n
Valu e T A = 25 oC -40 to 85 o C Min. T yp. Max. Min. Max. 1.5 5.5 8.0 1.5 9.0 1.5 1.5 6.5 7.5 10.0 10.0 1.5 1.5 12.0 11.0
Un it
ns ns ns
(*)
(*) Voltage range is 5V 0.5V
CAPACITIVE CHARACTERISTICS
Symb ol Parameter V CC (V) CIN Ci/o CPD Input Capacitance I/O Capacitance Power Dissipation Capacitance (note 1) 5.0 5.0 5.0 Test Co nditions Min. T yp. 5 10 23 Valu e T A = 25 oC Max. -40 to 85 o C Min. Max. pF pF pF Un it
1) CPD isdefined as the value of the IC'sinternal equivalent capacitance which is calculated fromthe operating current consumption without load. (Referto Test Circuit).Average operating current can be obtained by the following equation. ICC(opr) = CPD * VCC * fIN + ICC/n (per circuit)
TEST CIRCUIT
T EST tPLH , tPHL tPZL , tPLZ tPZH , tPHZ
CL = 50 pF or equivalent (includes jigand probe capacitance) RL = R1 = 500 orequivalent RT = ZOUT of pulse generator (typically 50)
SW IT CH Open 2VCC Open
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74ACT245
WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
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74ACT245
Plastic DIP-20 (0.25) MECHANICAL DATA
mm MIN. a1 B b b1 D E e e3 F I L Z 3.3 1.34 8.5 2.54 22.86 7.1 3.93 0.130 0.053 0.254 1.39 0.45 0.25 25.4 0.335 0.100 0.900 0.280 0.155 1.65 TYP. MAX. MIN. 0.010 0.055 0.018 0.010 1.000 0.065 inch TYP. MAX.
DIM.
P001J
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74ACT245
SO-20 MECHANICAL DATA
DIM. MIN. A a1 a2 b b1 C c1 D E e e3 F L M S 7.40 0.50 12.60 10.00 1.27 11.43 7.60 1.27 0.75 8 (max.) 0.291 0.19 13.00 10.65 0.35 0.23 0.50 45 (typ.) 0.496 0.393 0.050 0.450 0.299 0.050 0.029 0.512 0.419 0.10 mm TYP. MAX. 2.65 0.20 2.45 0.49 0.32 0.013 0.009 0.020 0.004 MIN. inch TYP. MAX. 0.104 0.007 0.096 0.019 0.012
P013L
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74ACT245
TSSOP20 MECHANICAL DATA
mm MIN. A A1 A2 b c D E E1 e K L 0o 0.50 0.05 0.85 0.19 0.09 6.4 6.25 4.3 6.5 6.4 4.4 0.65 BSC 4o 0.60 8o 0.70 0o 0.020 0.10 0.9 TYP. MAX. 1.1 0.15 0.95 0.30 0.2 6.6 6.5 4.48 0.002 0.335 0.0075 0.0035 0.252 0.246 0.169 0.256 0.252 0.173 0.0256 BSC 4o 0.024 8o 0.028 0.004 0.354 MIN. inch TYP. MAX. 0.433 0.006 0.374 0.0118 0.0079 0.260 0.256 0.176
DIM.
A
A2 A1 b e K c L E
D
E1
PIN 1 IDENTIFICATION
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Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement 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 STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a trademark of STMicroelectronics (c) 1999 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com .
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