DRV200S User Guide

Last updated: 2023-03-09 PDF version

DRV200S Low noise laser driver with external setpoint user interface — DRV200S user interface

Connections

Terminal block

VSI: Internal supply. Connect this pin to a 5V supply. Maximum current draw is 80 mA.
VSL: Laser supply. Connect this pin to a supply voltage between 3 V and 19 V depending on the required compliance voltage. Maximum current draw is equal to the laser current plus 20 mA. The laser supply is internally regulated with a linear regulator where the output voltage V_SET is controlled by the VSET trimmer (see Adjusting the compliance voltage section). The voltage drop in the linear regulator V_SL - V_SET must be kept above 0.5 V to ensure proper voltage regulation and below 2 V to limit power consumption.
EN: Laser Enable pin. Apply a voltage between 2.2 V and 4.5 V to enable the laser current.
ISET: Laser current setpoint input. Apply a voltage at this pin to set the laser current. The input has 2 kΩ impedance and is filtered by a second-order low-pass filter with 10 Hz cutoff frequency. Gain is 20 mA/V for the DRV200S-A-40, 100 mA/V for the DRV200S-A-200 and 200 mA/V for the DRV200S-A-400.
IMON: Laser current monitoring pin. The voltage at this pin is proportional to the laser current. Gain is 50 V/A for the DRV200S-A-40, 10 V/A for the DRV200S-A-200 and 5 V/A for the DRV200S-A-400. Output impedance is 1 kΩ.
LD+: Laser anode pin. Connect this pin to the laser anode.
LD-: Laser cathode pin. Connect this pin to the laser cathode.
RS: Do not connect.

Others

Switch: Enable / disable laser current

Adjusting the compliance voltage

The driver voltage V_SET at the test point VSET must be set according to the laser operating voltage and current:

DRV200S-A-40 Low noise laser driver with external setpoint safe operating area — DRV200S-A-40 (40 mA) safe operating area

DRV200S-A-200 Low noise laser driver with external setpoint safe operating area — DRV200S-A-200 (200 mA) safe operating area

DRV200S-A-400 Low noise laser driver with external setpoint safe operating area — DRV200S-A-400 (400 mA) safe operating area

V_SET can be adjusted between 2.4 V and 18 V with the VSET trimmer. When the board is powered off, adjust the voltage V_SET by using the formula V_SET = R_SET × I_SET, where R_SET is the resistance between GND and the VSET testpoint and I_SET = 100 µA for the DRV200S-A-40 and the DRV200S-A-200 and 200 µA for the DRV200S-A-400.

Current limit

Current limit can be adjusted with the ILIM trimmer that sets the resistance RLIM between GND and the ILIM test point.

Current modulation

The DRV200S can be modulated from DC to 6 MHz using the SMA connector. The MOD jumper allows to select between 3 modulation gains:

DRV200S-A-40

Low: 167 µA/V
Medium: 1.67 mA/V
High: 16.7 mA/V

DRV200S-A-200

Low: 833 µA/V
Medium: 8.33 mA/V
High: 83.3 mA/V

DRV200S-A-400

Low: 1.67 mA/V
Medium: 16.7 mA/V
High: 167 mA/V

Modulation range is ±1 V and input impedance is 50 Ω.