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Micrel, Inc.
2.5Gbps HIGH-SPEED LIMITING POST AMPLIFIER
SY88923
SY88923
FEATURES
s s s s s s s s Up to 2.5Gbps operation Low noise Chatter-Free LOS generation Open Collector TTL LOS output TTL /EN Input Differential PECL inputs for data Single power supply Designed for use with SY88922 and SY88904 or SY88905 s Available in a tiny 10-pin (3mm) MSOP
DESCRIPTION
The SY88923 limiting post amplifier with its high gain and wide bandwidth is ideal for use as a post amplifier in fiber-optic receivers with data rates up to 2.5Gbps. Signals as small as 5mVp-p can be amplified to drive devices with PECL inputs. The SY88923 generates a chatter-free Loss of Signal (LOS) open collector TTL output. The SY88923 incorporates a programmable level detect function to identify when the input signal has been lost. This information can be fed back to the /EN input of the device to maintain stability under loss of signal condition. Using LOSLVL pin, the sensitivity of the level detection can be adjusted. The LOSLVL voltage can be set by connecting a resistor divider between VCC and VREF. Figure 3 and Figure 4 show the relationship between input level sensitivity and the voltage set on LOSLVL. Figure 5 shows the relationship between input level sensitivity and resistor divider ratio. The LOS output is a TTL open collector output that requires a pull-up resistor for proper operation, Figure 1.
+5.0V SY88923 LOS 2.5k
APPLICATIONS
s s s s s 1.25Gbps Gigabit Ethernet 531Mbps and 1062Mbps Fibre Channel 622Mbps SONET Gigabit interface converter 2.5Gbps SDH/SONET
Figure 1. LOS Output with Desired Rise Time
BLOCK DIAGRAM
DIN
Limiting Amplifer ECL Buffer
DOUT DOUT
DIN VREF
Enable
VCC GND
Level Detect
EN
LOSLVL
LOS
M9999-060506 hbwhelp@micrel.com or (408) 955-1690
Rev.: E
Amendment: /0
1
Issue Date: June 2006
Micrel, Inc.
SY88923
PACKAGE/ORDERING INFORMATION
Ordering Information
/EN 1 DIN 2 /DIN 3 VREF 4 LOSLVL 5 MSOP K10-1 10 VCC 9 DOUT 8 /DOUT 7 LOS 6 GND
Part Number SY88923KC SY88923KCTR(1) SY88923KG SY88923KGTR(1)
Note: 1. Tape and Reel.
Package Type K10-1 K10-1 K10-1 K10-1
Operating Range Commercial Commercial Industrial Industrial
Package Marking 923 923 923 with Pb-Free bar-line indicator 923 with Pb-Free bar-line indicator
Lead Finish Sn-Pb Sn-Pb Pb-Free NiPdAu Pb-Free NiPdAu
10-Pin MSOP (K10-1)
PIN NAMES
Pin DIN /DIN LOS LVL /EN LOS GND /DOUT DOUT VCC VREF Type Data Input Data Input Input TTL Input TTL Output (Open Collector) Ground PECL Output PECL Output Power Supply Output Function Data Input Inverting Data Input LOS Limit Set Output Enable (Active Low) Loss of Signal Indicator (Active High) Ground Inverting Data Output Data Output Positive Power Supply Reference Voltage Output for LOS Level Set (see Fig. 3)
GENERAL DESCRIPTION
General The SY88923 is an integrated limiting amplifier intended for high-frequency fiber-optic applications. The circuit connects to typical transimpedance amplifiers found within a fiber-optics link. The linear signal output from a transimpedance amplifier can contain significant amounts of noise, and may vary in amplitude over time. The SY88923 limiting amplifier quantizes the signal and outputs a voltagelimited waveform. The /EN pin allows the user to disable the output signal without removing the input signal.
ABSOLUTE MAXIMUM RATINGS(1)
Symbol VCC DIN, /DIN DOUT, /DOUT TA Tstore Rating Power Supply Voltage Input Voltage Output Voltage (with 50 load) Operating Temperature Range Storage Temperature Range Value 0 to +7.0 0 to VCC VCC -2.5, VCC +0.3 -40 to +85 -55 to +125 Unit V V V C C
Note: 1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum ratlng conditions for extended periods may affect device reliability.
M9999-060506 hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88923
DC ELECTRICAL CHARACTERISTICS
VCC = +5V 10%, RLOAD = 50 to VCC-2V, TA = -40C to +85C
TA = -40C Symbol ICC IIL IIH VCMR Voffset LOSLVL VOL IOH VOH VOL VREF VIH VIL Parameter Power Supply Current(1) Min. -- -0.3(8) -- -- Max. 35 -- 20(5) 100(6) 100 VCC 0.5 250 TA = 0C Min. -- -0.3(8) -- -- Max. 35 -- 20(5) 100(6) 100 VCC 0.5 250 Min. -- -0.3(8) -- -- TA = +25C Typ. 21 -- -- -- -- -- -- -- -- Max. 35 -- 20(5) 100(6) 100 VCC 0.5 250 TA = +85C Min. -- -0.3(8) -- -- Max. 35 -- 20(5) 100(6) V mV V V uA mV mV V V V 100 VCC 0.5 250
VCC-880
Unit mA mA A
/EN Input LOW Current /EN Input HIGH Current Common Mode Range Differential Output Offset LOSLVL Level(2) Level(3) Leakage(4)
GND +2.0 VCC -1.0 GND +2.0 VCC -1.0 GND +2.0
VCC -1.0 GND +2.0 VCC -1.0 -- VREF -- --
-- VREF -- --
VCC-1085
-- VREF -- --
-- VREF -- --
LOS Output Low LOS Output
DOUT and /DOUT HIGH Output DOUT and /DOUT LOW Output Reference Supply(7) /EN Input HIGH Voltage /EN Input LOW Voltage
VCC-880 VCC-1025 VCC-880 VCC-1025 VCC-955 VCC-880 VCC-1025
VCC-1830 VCC-1555 VCC-1810 VCC-1620 VCC-1810 VCC-1705 VCC-1620 VCC-1810 VCC-1620 VCC-2.625 VCC-2.325 VCC-2.625 VCC-2.325 VCC-2.625 VCC-2.475 VCC-2.325 VCC-2.625 VCC-2.325
2.0 --
-- 0.8
2.0 --
5. 6. 7. 8.
-- 0.8
2.0 --
-- --
-- 0.8
2.0 --
-- 0.8
Notes: 1. No output load. 2. 223-1 pattern. 3. IOL = + 2mA. 4. VOH = 5.5V.
VIN = 2.7. VIN =VCC. IREF must be limited within -0.8mA (source) and 0.4mA (sink). VIN = 0.5V.
AC ELECTRICAL CHARACTERISTICS
VCC = +5V 10%, RLOAD = 50 to VCC - 2V, TA = -40C to +85C
TA = -40C Symbol PSRR VID tr, tf VOD tOFFL tOFFH tONL VSR HYS Parameter Power Rejection Ratio Supply(1) Min. -- 5 -- -- -- -- -- -- -- 5 2 Max. -- 1800 175 -- -- -- 0.5 0.5 0.5 50 8 TA = 0C Min. -- 5 -- -- -- -- -- -- -- 5 2 Max. -- 1800 175 -- -- -- 0.5 0.5 0.5 50 8 -- 5 -- -- -- -- -- -- -- 5 2 TA = +25C Min. Typ. 35 -- -- trin,tfin 600 200 0.1 0.1 0.2 -- 4.6 Max. -- 1800 175 -- -- -- 0.5 0.5 0.5 50 8 TA = +85C Min. -- 5 -- -- -- -- -- -- -- 5 2 Max. -- Unit dB Conditions Input referred, 55MHz
Input Voltage Range Output Rise/Fall Time Differential Output Voltage Swing(2) LOS Release Time(3) Minimum Input LOS Release Time(4) Maximum Input LOS Assert Time(3) LOS Sensitivity Range LOS Hysteresis
1800 mVp-p 175 -- -- -- 0.5 0.5 0.5 50 8 ps mV mV s s s mVp-p dB 223-1 pattern VID > 100mVp-p VID < 100mVp-p VID = 15mVp-p VID = 5mVp-p
Notes: 1. Input referred noise = RMS output noise/low frequency gain. 2. Input is a 622MHz square wave. M9999-060506 hbwhelp@micrel.com or (408) 955-1690
3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p. 4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p.
3
Micrel, Inc.
SY88923
DESIGN PROCEDURE
Output Termination The SY88923 outputs must be terminated with a 50 load to VCC - 2V (or thevenin equivalent). Layout and PCB Design Since the SY88923 is a high-frequency component, performance can largely be determined by board layout and design. A common problem with high-gain amplifiers is feedback from the large swing outputs to the input via power supply. The SY88923 ground pin should be connected to the circuit board ground. Use multiple PCB vias close to the part to connect to ground. Avoid long, inductive runs which can degrade performance.
PERFORMANCE CURVE
LOS Assert and Deassert Levels vs LOSLVL
100.00 90.00 80.00 70.00
Deassert
Level (mV)
60.00 50.00 40.00 30.00 20.00 10.00
4.01 4.13 4.26 4.38 4.51 4.63 4.75 4.88 2.53 2.65 2.77 2.90 3.02 3.14 3.27 3.64 3.76 3.39 3.52 3.89 5.00
Assert
0.00
LOSLVL (V)
0.1F 0.1F
DIN+ DIN- 50 VREF
Figure 4. 223-1 Pattern
50
0.1F
100.00 90.00
LOS Assert and Deassert Levels vs Resistor Divide
Figure 2. Differential Input Configuration
80.00 70.00
Deassert
Level (mV)
60.00 50.00 40.00 30.00 20.00
Assert
VCC
R1 LOSLVL R2 VREF
10.00 0.00
0.00 0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
Resistor Divider R2 / (R1 + R2)
Figure 5. 223-1 Pattern
Note: Resistor Divider = R2/ (R1 + R2) R1 + R2 5k Figure 3. LOSLVL Circut
M9999-060506 hbwhelp@micrel.com or (408) 955-1690
4
1.00
SY88923
20k
68
68
VREF OUT DIN DIN
RSET
TX_DATA+
SY88922
EN
200
200
TX_DATA-
OUT
RSER
BLM21A102S
Laser Module
ENABLE/DISABLE
VCC
GND
APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION
GBIC Terminal
IBIAS
MD IBIAS SET
20k
REXT
VCC
24
The value of RSER depends on the Laser Diode.
SY88905
LOSOUT LOSIN
RX_LOS
IBIAS FB IPIN SET
20k
1000pF
VCC
Photodiode Laserdiode
VCC
VCC VCC
68 68
GND
VREF VCC
82
DIN DOUT DOUT
130
200
200
LOSLVL
0.1F
VCC
0.1F
VCC
GND
VREF
Micrel, Inc.
20k
130
RX_DATA-
SY88923
M9999-060506 hbwhelp@micrel.com or (408) 955-1690
RX_DATA+
DIN
82
EN
LOS
5
Micrel, Inc.
SY88923
10-PIN MSOP (K10-1)
Rev. 00
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
http://www.micrel.com
The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2006 Micrel, Incorporated. M9999-060506 hbwhelp@micrel.com or (408) 955-1690
6

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