Stats

State Verified Answer
Replies 3
Subscribers 26
Views 4590
Members are here 0

PSpice derivative not smooth

BertRAMAerts over 1 year ago

This is my circuit:

What I do not understand is the un-stability of the derivative:

I would expect a flat line... What can be wrong

0 BertRAMAerts over 1 year ago

Of course a derivative of 200K=200000 is huge, atan(200000)-Pi/2=5E-6 so very very close to Pi/2.
Taking a much bigger max timestep of 0.5usec instead of 0.01usec gives a better result with much less noise.
Not sure why...
Cancel
Vote Up +1 Vote Down

Sign in to reply

Verify Answer

Cancel
+1 BertRAMAerts over 1 year ago in reply to BertRAMAerts

It was just a setting: I made the relative tolerance 10 times smaller than the default value:

and now the gain looks great even with very small timestep of 0.01 usec:
Cancel
Vote Up +1 Vote Down

Sign in to reply

Reject Answer

Cancel
0 AyushD over 1 year ago in reply to BertRAMAerts

You just tighten the accuracy and hence smooth line.
Cancel
Vote Up 0 Vote Down

Sign in to reply

Verify Answer

Cancel

Cadence Guidelines

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.