2.7Gbps, +3.3V DC-Coupled Laser Driver

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7

Pin Description

PIN

NAME

FUNCTION

1, 4, 7

Power Supply for Digital Circuits

2

DATA+

Positive Data Input

3

DATA-

Negative Data Input

5

CLK+

6

CLK-

8

LATCH

TTL/CMOS Latch Input. High for latched data, low for direct data. Internal 100k

Ω pullup resistor

9

ENABLE

TTL/CMOS Enable Input. High for normal operation, low to disable laser bias and modulation

current. Internal 100k

10

GND1

Ground for Digital Curcuits

11

BIASMON

Bias Current Monitor. Current into this pin is proportional to the laser bias current.

12

MODMON

Modulation Current Monitor. Current into this pin is proportional to the laser modulation current.

13

FAIL

TTL/CMOS Failure Output. Indicates APC failure when low.

14

APCFILT

15

GND4

Ground for Output Curcuitry

16, 18, 21

Power Supply for Output Circuitry

17

BIAS

Laser Bias Current Output

19

OUT+

20

OUT-

22

GND4

Ground for Modulation Current Source

23

GND3

Ground for APC Circuitry

24

MD

Monitor Diode Input. Connect this pin to a monitor photodiode anode. A capacitor to ground is

required to filter high-speed AC monitor photocurrent.

25

Power Supply for APC

26

CAPC

A capacitor connected from this pad to ground controls the dominant pole for the APC feedback

27

GND2

Ground for Internal Reference

28

N.C.

No Connection. Leave unconnected.

29

APCSET

A resistor connected from this pad to ground sets the desired average optical power. Connect a

100k

Ω resistor from this pad to ground if APC is not used.

30

MODSET

A resistor connected from this pad to ground sets the desired modulation current.

31

BIASMAX

A resistor connected from this pad to ground sets the maximum bias current. The APC function

can subtract from this maximum value but cannot add to it.

32

VCC2

Power Supply for Internal Reference