Who can explain the AC diagram of attached?

[chang830]

Hi,
I encounterd a strange phenominon of the phase digram in AC analysis.

Pls. take a look at the attached diagram. The phase is abruptly from the ~-180'C to 180'C at ~600mHz.


Would anyone pls. tell me what happed to it?


Thanks

 

[Fom]

+180 and -180 are the same. It seems the simulator or waveform viever changes phase by -360 if it exeeds +180.

 

[flushrat]

add .option unwrap in your hspice netlist
then the phase waveform will be continuous

 

[Kral]

chang830,
The abrupt step in phase is not real. Many programs do this to keep the phase plot a reasonable size.
Regards,
Kral