LM358: LM358 simulation behavior

Vitaliy Smirnov

Part Number: LM358
Other Parts Discussed in Thread: TINA-TI,

Tool/software:

Anybody tells me what is going on with the Tina-TI Simulation program (Version 9.3.200.277 SF-TI) behavior! The positive feedback works like negative feedback here!

11 months ago

0 Raymond Zhang1 11 months ago

TI__Guru* 77501 points

Hi Smimov,

I am using the same tool as you have.

Where did you get LM358's model? The Tina simulation tool is working fine. It is likely that your Spice model has Vin+ and Vin- input pin assignment are inverted somehow or similar strange thing that I am not aware of.

My simulation looks fine, which it works as comparator.

LM358 comparator.TSC

BTW, LM358 is unable to operate at +/-20Vdc. The max. recommending voltage is +/-18Vdc.

Best,

Raymond

0 Vitaliy Smirnov 11 months ago in reply to Raymond Zhang1

Prodigy 10 points

Hi Raymond,

Thank you for your reply.

This LM358 model is from Tina semiconductors library. And ideal OP Amp as well. Yes, your simulation looks good.

I don't think 20V supply here could make big difference. But I will change and try again. I switched this simulation to a regular

negative feedback configuration and I got the same.

0 Vitaliy Smirnov 11 months ago in reply to Vitaliy Smirnov

Prodigy 10 points

I tried with +-15V supply. The same.

0 Vitaliy Smirnov 11 months ago in reply to Vitaliy Smirnov

Prodigy 10 points

I tried the model of LM358 from this Tina Spice Macros library. It is the same.

0 Raymond Zhang1 11 months ago in reply to Vitaliy Smirnov

TI__Guru* 77501 points

Hi Smirnov,

I do not see that Tina has the LM358 Spice model. If you review the source of LM358 Spice model, it will tell you where the pin assignment should be.

Best,

Raymond

0 Vitaliy Smirnov 11 months ago in reply to Raymond Zhang1

Prodigy 10 points

I have downloaded the Tina from ti.com recently. May be the libraries were updated. Ther are two libraries there: one is in semiconductors section and the other is in Spice Macros section.

0 Vitaliy Smirnov 11 months ago in reply to Vitaliy Smirnov

Prodigy 10 points

Hi Raymond,

Changing configuration from positive feedback to regular negative feedback connection does not effect.

Best,

Vitaliy

0 Raymond Zhang1 11 months ago in reply to Vitaliy Smirnov

TI__Guru* 77501 points

Hi Smirnov,

You want to send me the Tina file. We have the latest LM358 Spice model that is available over the product website. I do not understand why you need to work on an outdated Spice model.