Other Parts Discussed in Thread: OPA857,
Hello together,
we're busy designign our own OTDR application related to TI's refernce design. In this application OPA857 is used as TIA for a connected APD.
Because of spacing requirements and other ideas we are thinking about testing the integrated new part LMH32401 in that application. With respect to datasheet LIDAR is noted as typical application.When regarding OTDR as one dimesional LIDAR its could work, we think.
But there a some restrictions we need help with or an idea how so solve this.
Datasheet of LMH32401 says part will only work with APDs connected with cathode to input and anode must be connected to a high negative voltage. Because of the fact that we must have the to do fine adjustment of APD voltage we must just a APD power supply circuit. Those parts are only avaible with a positive output.
Of course wie could try a flyback solution fo get the negative voltage but then spacing advantage is gone and fine adjustment might also be more complex.
This leads us to the following questions:
- Is there any chance to use LMH32401 with a positive APD voltage and anode connected to input? We already thought of using a capacitor for decoupling although we know that dark current compensation will not work in that case becaus dc path is missing.
- Is there any good suggest, idea or hint how to realize a compact negative APD voltage source with fine tuning option?
Thanks in advance
Christian
