OPA189: Asymmetrical Supplies?

John Douglass

Part Number: OPA189
Other Parts Discussed in Thread: TINA-TI

Hi,

We are considering the OPA189 for a MEMS based accelerometer. In simulation the SPICE model seems to have an aversion to asymmetrical power supplies. I would like to run it at +20,-5 V. Looking through the SPICE deck I see references to node "0". This seem a bit illogical given that the part has no gnd pin. I guess in simulation I'll have to run +/- 18V. That barely gives enough headroom. We need to slew 0 to ~17V in 7 us.

Merry Christmas!!

over 3 years ago

0 Michael Steffes over 3 years ago

Guru 48395 points

Part is rail to rail, all models have to have a ground node, but the external device does not.

Should work with asymmetric supplies , can you post TINA file - use the little paperclip in the ribbon

0 Tamara M Alani over 3 years ago

TI__Genius 10850 points

Hi John,

Thanks for your post, I can help you. Asymmetrical supplies are just fine on the OPA189. Are you referring to the TINA model or the P-SPICE model? I'm assuming the P-SPICE model, in which case, this is a known issue. Our SPICE expert is aware of this and has it on his list to resolve and update to the web.

In the meantime, can you try TINA-TI to create your circuit: https://www.ti.com/tool/TINA-TI

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi John,

can you share your TSC-file?

Kai

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OPA189: Asymmetrical Supplies?