<@U01819B63HP> I have added the necessary large sh...
# analog-design
@User I have added the necessary large shunt resistors to solve the singular matrix issue. Now, I am trying to debug the DPDT switch. It seems to be working (See
) , with the exception of the first 4 waveforms (red, blue, orange, green)
@Tim Edwards I modified the control voltages for the DPDT switch as well as added R46 and R47 , I now have a better picture of why the DPDT switch is not working well.
@Stefan Schippers
red and blue waveforms are for drain and source nodes of M9 respectively
orange and green waveforms are for drain and source nodes of M12 respectively
both M9 and M12 are pass transistors
@Stefan Schippers it seems that the DPDT switch is also working now. Please correct me if wrong.
@promach for the RF details i am not the right one to ask to, I have one concern about the 1 ohm resistors shunting Vd9 and Vd12 to VCC_2: these are blocking all frequencies. Are you sure this is ok?
the 1 ohm resistor is only there for testing, it will be removed later
@Stefan Schippers
ok, fine 🙂
I have only tested direct connection between drain and source of the pass transistor
I have not tested using
@Stefan Schippers I mean the cross-connection of the DPDT switch
for the DPDT switch, I am not sure in what situations (in terms of M2 and M3) should I turn on each of four different mosfets M1 ?
@Stefan Schippers I am finding a way to test all 4 connections (2 going through the pass transistors, the other 2 going through the cross-connections) separately (time-multiplexed) using only a single transient simulation with all the control voltages using only PULSE() spice syntax with varying frequencies or initial delay
Note: if I am connecting Pole 2 to Pole 3 for example, then I would want to ground Pole 1 and Pole 4.
I just noticed that there are only 3 different connections configurations. 1. P1 connects P3 , P2 connects P4 2. P1 connects P3 , P1 connects P4 3. P2 connects P3 , P2 connects P4 Please correct me if I miss anything.
The DPDT switch is also working for cross-connection which I forgot to include in previous message regarding different connections configurations
@Stefan Schippers the real issue comes now : which connection configuration does the phase shifter circuit actually use ?
@Stefan Schippers @Tim Edwards in the picture just above, the DPDT circuit block shows all 4 nodes are connected together which is just simply not realistic in reality. Please correct my understanding if wrong.