I am using the HMC799 with APD input. As the APD can generate high currents I have used a Schottky diode connected to the input to divert some of this current. The internal bias on the CFILT pin is 2.2V when Vcc is 5V. I notice on a previous post on this subject that external resistors setting the bias at CFILT to be Vcc/2 or 2.5V in this case. Is there a reason for doing this or can I revert to the internal supply biassing of 2.2V?
I am driving the input with a 1ns pulse width. The output pulse width of the amplifier varies up to several hundred ns under overload conditions.