December 2019  33  LDC-3706 Series Laser Controller 
 
IC-I SENSORS – When an IC-I sensor is selected, the LDC-3706 Laser Controller measures 
temperature based on the current passed through the sensor. An example of an IC-I sensor is 
the Analog Devices AD590. This device delivers 1 µA/K or approximately 298 µA at 25°C.  The 
(+) terminal of the transducer should be connected to the Sensor+ pin and the (-) terminal 
should be connected to Sensor-.  The nominal slope for the AD590 is 1 µA/K and the offset is 
nominally 0 µA but both can be adjusted to calibrate a particular sensor by entering the TEC 
parameter menu. 
 
The sensor will have approximately 9 V across it at 25°C but will vary over the temperature 
range.  In IC-I sensor mode, the LDC-3706 has a sensor current limit of 600 µA, which is 
approximately 325°C. 
 
 
For IC-Current sensors used with the LDC-3706 the 4-wire sensor measurements 
(pins 7 and 8) should not be connected.  The use of the 4-wire sensor will cause 
inaccurate sensor measurements. 
IC-V SENSORS – When an IC-V sensor is selected the LDC-3706 instrument measures 
temperature based on the voltage across the sensor. An example of an IC-V sensor is the 
National Semiconductor LM335A. This device delivers 10 mV/K or approximately 2.98 V at 
25°C.  The (+) terminal of the transducer should be connected to the Sensor+ pin and the (-) 
terminal should be connected to Sensor-.  The nominal slope for the LM335A is 10 mV/K and 
the offset is nominally 0 mV but both can be adjusted to calibrate a particular sensor by entering 
the PARAM menu. 
 
The sensor will have approximately 1 mA of current through it at all times.  In IC-V sensor mode, 
the LDC-3706 instrument has a sensor voltage limit of 6 V, which is approximately 325°C.