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Analog Technologies

ATLS25A219D

32V 25A Constant Current Laser Driver

Figure 1. Physical Photo of ATLS25A219D

FEATURES

∼40V

(input voltage)

≥95%

∼10kHz

APPLICATIONS

Drive one or multiple laser diodes for DPSSL, EDFA, and

fiber lasers with low noise, high stability and high

efficiency.

DESCRIPTION

This laser driver, ATLS25A219D, is an electronic module

that has all the valuable and important, but often difficult to

achieve simultaneously, features: wide input and output

voltage range, high output current capability, high efficiency,

at 500kHz), wide modulation bandwidth, and small size. The

driving one or multiple serial laser diodes at the same time, for

up to 25A well controlled current at high efficiency. The

extremely low noise between DC 0.1Hz ~ 10Hz and low DC

current drift make it ideal for driving high current laser diode

arrays. Because of the high efficiency, the build-in small heat

sink is sufficient to dissipate the heat generated by the driver, no

additional heat sink is needed. The fully shielded case blocks all

the incoming and outgoing EMIs (Electro-Magnet Interferences).

Therefore, this laser will not interfere other surrounding

electronics, nor will be interfered by them. The small package

saves valuable PCB space in laser systems. Figure 1 shows

physical photo of the ATLS25A219D.

This laser driver has two current set ports which can digitally be

controlled to switch between them for setting the output current.

This feature allows modulating the laser digitally with 2 preset

current values.

The actual laser current and laser driver temperature is

monitored by dedicated port. In case the laser driver temperature

exceeds the limit, 120

°C, the laser driver will shut down the

output stage by itself and force the laser drive into Standby Mode.

There is a loop good indication output to tell if the laser driver

works well.

The laser driver has 3 states: Operation, Standby and Shutdown.

Under Standby mode, all the laser driver components will be

working except the output stage, see Figure 4. Under Shutdown

mode, all the components of the laser driver stop working and

the power supply current is reduced to < 2mA.

This laser driver generates a high accuracy high stability low

noise. When outputting 25A to the laser, the noise current is

output current stability is <100ppm/

°C, It comes with a low

noise high stability voltage reference which can be used for

setting the output current and also be used as the reference

voltage for the ADCs (Analog to Digital Converters) and/or

DACs (Digital to Analog Converters).

The ATLS25A219D uses a constant frequency high efficiency

PWM output stage. Its switching signal is taken out through a

buffer at the SYNO port, pin 10, which can be used by other

switch mode electronics as the trigger signal to avoid frequency

beating interference, if the free-run frequency is around 500kHz.

types of packages can only be soldered manually on the

board by a solder iron of < 310

°C (590°F), do not use a reflow

oven to solder this laser driver.

For noise sensitive applications, please be aware that this laser

driver has very low noise between DC to 10Hz, but there is a

500kHz sine-wave ripple voltage, around 10mVpp, present at

the output, the LDA port.