speaking of spice... any slick way to sweep two inputs at a time?

Question

Let me explain the question in more detail..

Talking about .AC analysis and lets say you sweep the frequency response of a differential op amp. You can plot several outputs (traces) at the the same time.

But lets say I want to sweep the freq response of the desired differential input and the frequency response of the common mode rejection at the same time. Instead of one input and two outputs, I have 2 inputs and one output.

Seems there is no simple way to do it.

I know you can make a sub circuit and hook it up both ways and get both results together, or use .step.

Anybody know of a neat trick to do this more simply?

Mark

Phil Hobbs · Accepted Answer

You can use .STEP PARAM and derive both inputs from the parameter using curly brackets in the source expressions.CheersPhil Hobbs

Jim Thompson · Answer

Yep.  As I indicated in a prior post.  I've actually done as many as 8different parameters sweeping a single parameter named "INDEX" :-)In Mark's case declare a parameter "PASS"Then have two AC sources...VAC1 has value {PASS}VAC2 has value {1-PASS}.STEP PARAM PASS LIST 0 1		                                        ...Jim Thompson-- | James E.Thompson, CTO                            |    mens     || Analog Innovations, Inc.                         |     et      || Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    || Phoenix, Arizona  85048    Skype: Contacts Only  |             || Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  || E-mail Icon at  |    1962     |             I love to cook with wine.     Sometimes I even put it in the food.

Mark · Answer

8=A0 =A0 ...Jim Thompson=A0 =A0| =A0 =A0mens =A0 =A0 |=A0 | =A0 =A0 et =A0 =A0 =A0|=A0|=A0 =A0 =A0 |thanksMark

speaking of spice... any slick way to sweep two inputs at a time?

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