sy88232l Micrel Semiconductor, sy88232l Datasheet - Page 4

• Manufacturer Part Number: sy88232l
• Description: 2.5gbps Laser Diode Driver With Integrated Limiting Amplifier
• Manufacturer: Micrel Semiconductor

Pin Description (continued)
Micrel, Inc.
June 2009
5, 8, 16, 24, 29
Pin Number
17, 20, 32
12
13
14
15
18
19
21
22
23
24
25
27
28
30
31
APCFAULT
MODMON
Pin Name
BIASMON
BIASMAX
MODSET
APCSET
ROUT+
ROUT-
MOD+
MOD-
RSSI
RIN+
BIAS
GND
RIN-
MD
Pin Function
Bias current setting and control. The bias current is set by installing an external resistor from this
pin to ground or using a current source. Connect a 50kΩ resistor to GND for open loop operation.
Modulation current setting and control. The modulation current is set by installing an external
resistor from this pin to ground or using a current source.
Install a resistor between this pin and GND to set the maximum bias current for the closed loop
operation. The APC loop controls the bias current up to the level of BIASMAX. When the bias
current reaches the maximum value set through this pin, the driver continues to sink a current
equal to this maximum. For open loop operations, this pin sets the bias current.
Modulation Current Monitor. Provides a current, which represents 1/100 of the modulation
current. Install a resistor between this pin and GND to convert that current to a voltage
proportional to the modulation current.
Inverted modulation current output. Provides modulation current when input data is negative.
Non-inverted modulation current output. Provides modulation current when input data is positive.
Bias current output, sources current when /TXDIS is high. Connect to the cathode of the laser
through a resistor.
Input from the laser monitoring photodiode. Connect to the anode of the laser photodiode for APC
operation.
Bias Monitor. Provides a current, which represents 1/50 of the bias current. Install a resistor
between this pin and GND to convert that current to a voltage.
Received Signal Strength Indicator. Install a resistor from this pin to GND to get a voltage
proportional to the received signal.
Indicates APC failure when High. Active High TTL/CMOS. Use a 10kΩ Pull up.
SY88232L: Post amplifier Non-inverting input data. Internally terminated with 50Ω to a reference
voltage.
SY88232AL: Post amplifier Non-inverting input data. No internal termination.
SY88232L: Driver inverting input data. Internally terminated with 50Ω to a reference voltage.
SY88232AL: Driver inverting input data. No internal termination.
Post Amplifier Complementary CML data output.
Post Amplifier true CML data output.
Ground. Ground and exposed pad must be connected to the plane of the most negative potential.
Supply Voltage. Bypass with a 0.1µF//0.01µF low ESR capacitor as close to VCC pin as possible.
4
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SY88232L/AL