OPA2626: OPA2626 PSpice very strange results

Andree Buechner

Part Number: OPA2626
Other Parts Discussed in Thread: OPA626

Hello,

I'm simulating a simple noninverting circuit with the OPA626 in OrCAD PSpice 17.2. It runs fine, if the voltage at the +Input is 0.5 * (VCC-VEE). If it deviates by an offset from this (for instance by 150 mV), I get very strange results in transient simulation (see appendix). AC simulation doesn't give any useful result anymore.

I would like to have a working PSpice-Model of the OPA626.

Regards!

Andree

Transient.pdf 5633.SCHEMATIC1 _ PAGE1.pdf OPA626-Test-PSpiceFiles.zip OPA626.lib

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Andree,

you must not exceed the common mode input voltage range of OPA626, which is from 0V to 3.3V - 1.15V = 2.15V here:

andree_opa626.TSC

Kai

0 Andree Buechner over 4 years ago in reply to kai klaas69

Prodigy 70 points

Hi Kai,

Thanks for answering. But I see this even with a change of 150 mV from mid-supply only e.g. for 1.5 V or 1.8 V at the positive input. This should be completely in the common mode range. See the result for a sine wave with +/- 100 mV at 1.5 V DC level for 3.3 V supply.

Andree

Transient2.pdf

0 Hasan Babiker31 over 4 years ago in reply to Andree Buechner

TI__Genius 15565 points

Hello Andree,

Please try the following:

5265.OPA626.lib

It looks like the issue is with the set initial conditions within the device.

Best,

Hasan Babiker

0 Andree Buechner over 4 years ago in reply to Hasan Babiker31

Prodigy 70 points

Hello Hasan,

I tried the changed lib for the OPA626. Unfortunately it doesn't find the bias point now and gives a Divide by Zero simulation error.

Regards,

AndreeTest.zip

0 Hasan Babiker31 over 4 years ago in reply to Andree Buechner

TI__Genius 15565 points

Hello Andree,

Would you be able to provide a copy of your pspice project? Please use the 'File -> Archive Project' option to do this.

Best,

Hasan Babiker

0 Andree Buechner over 4 years ago in reply to Hasan Babiker31

Prodigy 70 points

Hello Hasan,

Yes, of course.

Regards

Andree

OPA626-Test-2021-02-16T14-52.zip

0 Hasan Babiker31 over 4 years ago in reply to Andree Buechner

TI__Genius 15565 points

Hello Andree,

Thanks for bringing up this issue, we will need to investigate further. For now please use the original .lib file.

For transient simulations, the results should be valid after the spike in voltages. For AC sims, however, you will need to use a dual supply condition. You can also run your single supply sims in TINA without issue.

Best,

Hasan Babiker

Amplifiers

Amplifiers forum

OPA2626: OPA2626 PSpice very strange results