FOA2322A Datasheet, PDF (7/37 Pages) Infineon Technologies AG – 3.2 Gbi t /s Laser Driver IC for Telecom and Datacom Applications

FOA2322A
Overview
Mode 2: The modulation current is controlled by using a low frequency pilot signal. The
controller cutoff frequency is adjustable by external capacitor (C_MOD). Mode 2 is suitable
for data rates 1.25 Gbit/s (depending on laser diode).
There is an option for using data input latch.
Input Signal Monitor
An input signal monitor circuit delivers a logic signal HWA and an internal signal which
is used for laser disabling if data input is constantly high or low.
Bias Control / Bias Generator
The bias controller controls the LD optical output power by adjusting the bias current.
The controller cutoff frequency is adjustable by external capacitor (C_BIAS). A min. cutoff
frequency is integrated. The laser bias current will start at < 500 µA after laser enable.
Laser Supervisor / V_CC Supervisor
The laser supervisor circuit monitors the laser output power by the means of monitor
diode feedback. The voltage generated by monitor diode circuit is compared to a
reference. If the input voltage deviates more than ±2 dB (optical power ±1 dB) from this
reference the laser diode is switched off and a fault indication is generated. The V_CC
supervisor monitors the circuit power supply and switches off the laser if the V_CC level is
below the reset threshold. It is keeping the laser output down for the adjusted delay time
(power on delay) after V_CC has risen above the V_CC reset threshold.
Preliminary Data Sheet
3
2001-05