Bad OpAmp Spice Models?

Question

I'm trying to make a list of OpAmp Spice models that either poorly model power supply currents, or not at all.

Suggestions, hopefully with details of how they deviate from the real device, would be appreciated.

Thanks! ...Jim Thompson

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.

RobertMacy · Accepted Answer

Have you ever been bit by a model that didn't show the difference in GBW   product for when the device was pulling UP versus when the device was   pulling DOWN?

Jim Thompson · Answer

Was it the GBW that got you or slew rate differences between UP and DOWN? I find it hard to imagine a "modern" OpAmp with significant GBW difference UP or DOWN.  Way back in the past I know of fully dual-path designs that could do that. 		                                         ...Jim Thompson --  | James E.Thompson                                 |    mens     | | Analog Innovations                               |     et      | | Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | | San Tan Valley, AZ 85142   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.

RobertMacy · Answer

I don't think was slew rate limiting but as you said 'dual path' design.    quite old something like the CA3130 ?

Jim Thompson · Answer

OK.  Now I understand.  BCML: Before current mirror loads ;-) Resistive pull-ups, current pull-downs. I've found an even better way to model power supply current, much better than yesterday's post (I didn't show the math, but it could be far simpler :-) It even can be tacked onto Spice models that lack any power supply pins. So back to playing, then I'll release an upgraded configurable OpAmp model. 		                                         ...Jim Thompson --  | James E.Thompson                                 |    mens     | | Analog Innovations                               |     et      | | Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | | San Tan Valley, AZ 85142   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.

Tim Wescott · Answer

So, you're working on a model for the people who do the "connect a PNP  booster to the power supply pin" dodge? --  Tim Wescott Wescott Design Services

Jim Thompson · Answer

Not specifically for that application.  Just generally.  Since that seems a common complaint. But I've done that very "dodge" myself.  Early '70's, LDO with 2N2907 plus LM741 ;-) Worked a peach EXCEPT I found out that not everyone's 741 was actually the same circuit schematic... I was making hybrids at the time, 741 in chip form. 		                                         ...Jim Thompson --  | James E.Thompson                                 |    mens     | | Analog Innovations                               |     et      | | Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | | San Tan Valley, AZ 85142   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.

Bad OpAmp Spice Models?

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