FOA2322A Datasheet, PDF(27/37 Page) Infineon Technologies AG – 3.2 Gbi t /s Laser Driver IC for Telecom and Datacom Applications

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FOA2322A Datasheet, PDF (27/37 Pages) Infineon Technologies AG – 3.2 Gbi t /s Laser Driver IC for Telecom and Datacom Applications

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FOA2322A

Pin Description

Table 6

Pin Definitions and Functions (contâd)

Signal Name Function

Explanation

IBIAS

Bias Output

A sink current drawn by IBIAS determines the laser

diode bias current.

CBIAS

MPOUT

Control

Monitor Output

The bias controller characteristic is set to an

i-controller. The cutoff frequency can be decreased

by an external capacitor at CBIAS to VEE.

MPOUT is an open collector output for pulling up a

resistor to monitor the deviation of the optical

power over the monitor diode current. Let open if

not used.

RPOUT

Control

A resistor between RPOUT and VEE can adjust the

relation of optical power measured over the

monitor diode current to output current at MPOUT.

Let open if the monitoring of the optical power is not

used.

VBIAS

Bias Output

This output can be connected to the base of an

external bias current NPN transistor. It can be

leave open if not used. It is dedicated for

applications which can not use the internal bias

transistor. Base of the output current mirror 1:25.

LDOFF

RSTN

Monitor Diode

Input

Laser Shut Down

Output

Logic Input

This is the controller feedback input. The voltage at

this input represents the monitor diode current and

by this the laser output power. The bias current will

be controlled to an equal level of VMD and VMDR.

Whenever the laser diode is disabled LDOFF will

deliver a high voltage level closed to VCC. If the

laser diode is enabled there is a sink current to

drive the base of an external pnp transistor to

support a laser diode supply shut down. If not used

this output can be leave open without Laser Driver

performance restrictions. There is an internal pull

up resistor between LDOFF and VCCA of 10k.

Low active reset input. This input resets the LF

indication if present. Further the laser diode is held

within shut down mode if this signal is at low level.

For constant laser diode enable this signal can be

tied to VCC.

Preliminary Data Sheet

2001-05

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