Wavelength Electronics LDTC0520, Datasheet And Operating Manual

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LDTC0520 / LDTC1020 LASER DIODE AND TEMPERATURE CONTROLLER
Table 2. Control and Monitor Transfer Functions
FUNCTION LDTC0520 LDTC1020 DESCRIPTION
EXT LD SET, CC Mode 250 mA / V 500 mA / V
External setpoint input to control the laser drive current in Constant
Current mode.
EXT LD SET, CP Mode 1 mA / V
External setpoint input to control the photodiode current in Constant
Power mode.
LD P MON 1 mA / V
The power monitor transfer function can be modified by changing a
resistor on the circuit board. Contact the factory for details.
LD I MON 250 mA / V 500 mA / V The laser current monitor indicates the current driven to the laser.
I
LIM
(Internal Test Point) 250 mA / V 500 mA / V Refer to page 20 for location of the I
LIM
test point on the circuit board.
ACT T M 1 V / V
The ACT T M voltage matches the voltage drop across the temperature
sensor.
SET T M 1 V / V
The SET T M voltage matches the setpoint voltage set by the onboard
trimpot or the EXT T SET input (pin J2‑11).
EXT T SET 1 V / V The external temperature setpoint input.
Table 3. Wiring Diagram Reference and LIM Trimpot Functions
SENSOR TYPE
LOAD
TYPE
V
DD_WTC
AND V
S
TIED
FIGURE, PAGE LIM A TRIMPOT LIM B TRIMPOT
NTC
(Thermistor)
TEC Either Figure 11 on page 12 Cooling Current Limit Heating Current Limit
Heater*
Yes Figure 15 on page 16
Set to OFF (fully CCW) Heating Current Limit
No Figure 16 on page 16
PTC
(RTD, LM335, etc)
TEC Either Figure 17 on page 16 Heating Current Limit Cooling Current Limit
Heater*
Yes Figure 18 on page 16
Heating Current Limit Set to OFF (fully CCW)
No Figure 19 on page 16
* Setting the LIM A and LIM B trimpots requires a special procedure when using a resistive heater.