AnsweredAssumed Answered

HMC849ALP4CE SPDT not working

Question asked by erez.benari on Mar 15, 2016
Latest reply on Mar 31, 2016 by s.ilke

Dear all,


I'm using the hmc849alp4ce switch to select which channel to be transferred to the rest of the chain. That is, there are two different RF signals on each of RF Port 1 and RF Port 2 that I wish to pass on to RFC Port.


I'm working around 5.9GHz and placed a 1.6 pF DC block caps on each port.


The control bit appears well and the enable pin is tied to GND.


The problem is simple - the switch doesn't apear to be working. No matter what the state of the control pin, I still observe -25dB loss when RF2 should be connected to RFC and similarly RF1 to RFC.

When I change between states there is a slight improvement towards -23dB. either way, it's not working.


Vdd is fine and according to specs.


My questions are:

1. The switch is bidirectional - Is that correct? I assume it is but just to make sure.


2. Do you think that 1.6pF caps should be replaced to different vals? The datasheet suggests 100pF but this values look too much for me considering 5.9GHz.


Thank you,