DRV200S User GuideLast updated: 2020-05-04 PDF version
VSI: Internal supply. Connect this pin to a 5V supply. Maximum current draw is 80 mA.
VSL: Laser supply. VSL can be set 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 VSET is defined by the VSET trimmer (see Adjusting the compliance voltage section). The voltage drop in the linear regulator VSL - VSET 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 mV/mA for the DRV200S-A-40, 10 mV/mA for the DRV200S-A-200 and 5 mV/mA 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.
- Switch: Enable / disable laser current
Adjusting the compliance voltage
The driver voltage VSET at the test point VSET must be set according to the laser operating voltage and current:
VSET can be adjusted between 2.4 V and 18 V with the VSET trimmer. When the board is powered off, adjust the voltage VSET by using the formula VSET = RSET × ISET, where RSET is the resistance between GND and the VSET testpoint and ISET = 100 µA for the DRV200S-A-40 and the DRV200S-A-200 and 200 µA for the DRV200S-A-400.
Current limit can be adjusted with the ILIM trimmer that sets the resistance RLIM between GND and the ILIM test point.
The DRV200S can be modulated from DC to 6 MHz using the SMA connector. The MOD jumper allows to select between 3 modulation gains:
- Low: 200 µA/V
- Medium: 2 mA/V
- High: 20 mA/V
- Low : 1 mA/V
- Medium: 10 mA/V
- High: 100 mA/V
- Low : 2 mA/V
- Medium: 20 mA/V
- High: 200 mA/V
Modulation range is ±1 V and input impedance is 50 Ω.