Virtuoso Schematic Editor: Is there a built-in or SKILL to change name & parameters of multiple instances at the same time?

Hi Perry,

There's no built-in function to do that, and to handle the generic situation would need some SKILL code (not hard to write - I'm not aware of any existing SKILL code to do this).

Why do you need to do this? This is bad for simulator performance (it's OK with APS, because that converts parallel instances back into m-factor, but for standard Spectre, it would not). It also leads to larger netlists - so I'm interested as to why you want to do this.

Andrew.

Hi Andrew,

Thanks for the quick reply.
This is a common practice on the technology I am working on.
Based on the manual I am using, this is the reason:
"It is highly recommended using m=1 and ng=1 in mismatch Monte Carlo simulations whenever accuracy is required in design blocks which are sensitive to device mismatch. Multiparallel device connections are to be created by applying the M0<0:5> notation rather than by making use of the m-factor."

Understood, although you might want to know that Spectre has a way of handling that. See:

How does spectre apply correlation between m-factor devices during Monte Carlo simulation?

and the older article:

Monte Carlo should take m into account for mismatch

Note that this nullmfactorcorrelation doesn't work correctly if using TMI models, but they take into account the multiplicity factor on the transistors into account anyway when computing the mismatch.

Regards,

Andrew.

Understood, although you might want to know that Spectre has a way of handling that. See:

How does spectre apply correlation between m-factor devices during Monte Carlo simulation?

and the older article:

Monte Carlo should take m into account for mismatch

Note that this nullmfactorcorrelation doesn't work correctly if using TMI models, but they take into account the multiplicity factor on the transistors into account anyway when computing the mismatch.

Regards,

Andrew.