FQ1076: We would like to use the WLD3343 and WTC3243 to control a fiber-coupled laser diode which has laser diode anode ground. This ground is connected via the case to the thermistor ground. We are not using the photodiode, we scan through a range of currents to wavelength-tune the laser. When I look at your specification for the WLD3343, the picture on page 13 shows the laser diode anode connected to pin 14 i.e. 5V. None of the other circuits show a grounded laser anode. Is the WLD3343 in fact compatible with an anode ground system? I'm worried because I can't see how it can be, if its supply is 0 and 5V, yet I need to connect the cathode to something less than 0V.
Applies to these products:
WLD3343
WTC3243
The laser diode anode connected to Pin 14 on the WLD3343 will be connected to negative 5V. Follow this link to a diagram that shows how to connect your particular laser to the WLD3343. On the WTC3243, you will connect: Pin 2 to the voltage setpoint Pin 14 to the + side of your voltage supply (+5-30V) Pin 13 to the - side of your voltage supply (+5-30V) and one side of your laser's thermistor Pin 12 to the + side of the thermoelectric in your laser Pin 9 to the other side of your laser's thermistor. On the WLD3343, you will connect: Pin 2 to the -voltage setpoint Pin 7 to the - side of your voltage supply (-5-12V) Pin 11 to the cathode of your laser diode Pin 14 to the anode of your laser diode and the + side of your voltage supply (-5-12V). If you do choose to use the photodiode, you will want to connect it as shown in the diagram. The anode of the photodiode in your laser should be connected to RPD, with the other side of RPD connected to GND The cathode of the photodiode in your laser should be connected to either the laser diode anode or the laser diode cathode.
