3.0V to 5.5V, 2.5Gbps VCSEL

and Laser Driver

6

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Pin Description

PIN

NAME

FUNCTION

1TC

Temperature Compensation Set. The resistor at TC programs the temperature-increasing component

of the laser-modulation current.

2

FAULT

Fault Indicator. See Table 1.

3, 9

GND

Ground

4

TX_DISABLE

Transmit Disable. Laser output is disabled when TX_DISABLE is high or left unconnected. The laser

output is enabled when this pin is asserted low.

5

PORDLY

Power-On Reset Delay. A capacitor connected between PORDLY and GND can be used to extend the

delay for the power-on reset circuit. See the Design Procedure section.

6, 16, 19

Supply Voltage

7

IN+

Noninverting Data Input

8

IN-

Inverting Data Input

10

MON1

Attaches to the emitter of the bias driving transistor through a 10

Ω resistor. See the Design Procedure

section.

11

MON2

This pin attaches to the emitter of the bias driving transistor. See the Design Procedure section.

12

COMP

A capacitor connected from this pin to ground sets the dominant pole of the APC loop. See the Design

Procedure section.

13

MD

Monitor Diode Connection. MD is used for automatic power control.

14

SHDNDRV

Shutdown Driver Output. Provides a redundant laser shutdown.

15

BIAS

Laser Bias Current Output

17

OUT+

Positive Modulation-Current Output. Current flows from this pin when input data is high.

18

OUT-

Negative Modulation-Current Output. Current flows to this pin when input data is high.

20

MODSET

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

EP

Exposed Pad

Ground. This must be soldered to the circuit board ground for proper thermal and electrical

performance. See the Layout Considerations section.