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[SOLVED] Simulating AC conditions on Op-Amps

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vkem

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Okay,

Here is an interesting one. I've made up this SPICE OP-AMP model for a Texus TLV2442 Op Amp (as per the data sheet). I'm using Microcap. The AC response is fine if you use a split supply, like +/- 10v. But, on a +5/0v supply, the AC response is the same, but the reported gain is something silly (like -80dB).

The op-amp is designed for single supply
use. Is this a model problem or a limitation
of the SPICE model for op-amps.

Has anyone else had this split supply/single supply problem with SPICE op-amp models?

What do I think of Microcrap....Hmmm...:sad:

Vkem
 

IBall

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Have you successfully modelled other single supply opamps?
Do you know if this model has been used at 5V on another flavor of spice?

I have not used Microcap, but I would suspect the problem is in the model.
 

tichy

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Hi,
perhaps you could publish the model/schema so we can compare it to PSPice.
cya tichy
 

KARLZ

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hi
let us see your circuit first. then we can judge about it!
thx
 

gosth700

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I got the same problem whith MAX418 using the supplied spice model from the manifacturer(Maxim) .


<font size=-1>[ This Message was edited by: gosth700 on 2001-06-02 01:15 ]</font>
 

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vkem

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I have tried several circuits, all very simple, one of them is a standard buffer follower and the other is an open-loop gain measurement circuit (signal into +, 1k to GND on -, 100k to ground on output). The data sheet does not quote open loop gain and thus I needed to know where the dominant poles are for stability analysis.

Unfortunantly I don't have the model with me,
but I'll get it early next week and post it. I am confident there are no problems with the circuit, because I have loaded sample circuits from Microcap and they have the same problem. I am beginning to think it is a model problem.

However, it is interesting to hear someone has the same problem with a Maxim model.

Vkem
 

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