Hi,
I am trying to figure out a way to plot gm/Id for a transistor within LTspice. I am using as a starting point the schematic in the example MOSFET parameter sweep, MOS_gm_gmb_gds_ro.asc , within Examples\Examples\Educational\MOSFET parameter sweep\ .
In short, I am stepping the W/L and biasing sources and running .OP and .AC LIST 1 analysis . The example computes gm, gmb, gds, using the small-signal values from the AC analysis.
To plot gm/Id I would need to obtain the bias current of the NMOS transistor, either from the DC current through the voltage sources or through the device itself. Is there a way to refer to this current from the waveform viewer, maybe a trick I am missing ? The Spice Log file lists the device operating point for just one iteration, so I don't see how to extract the bias information for the steps, which is obviously being computed prior to the each AC analysis.
In short, given a sequence of AC analysis, how can I obtain/extract the bias point information for the circuit/devices, and if possible refer/use it within the waveform view when plotting ?
Helmut, can you help ? Mike, are you out there ? Fellow users, any ideas/work arounds ?
Thanks in advance for any help!
