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OPA659: OPA659 Quiescent current

Part Number: OPA659
Other Parts Discussed in Thread: OPA653, OPA656


I have one question about Iq of OPA659.

According to datasheet, Iq spec is defined 32mA(typ).

I think that this is a little high comparing other OPAMP which have similar BW spec.

So, can you confirm whether this is typo or not ?

Best Regards, 

  • Hi Ryuuichi,

    it's not unusual that a HF OPAmp providing ultra low distortion draws a somewhat higher supply current. This can result from the output stage running in class A mode rather than in class AB or even class B mode.


  • Actually guys, 

    Part of a family of JFET parts we developed (table 5) - this one is using the high transconductance input stage along with higher Iq to get the very high slew rate in a unity gain VFA. Nothing to do with the output stage which is topologically class AB and stays that way - The supply current is a tested spec so what you see in the datasheet is correct. If you don't need the slew rate, go to the OPA656. And actually, that table 5 in the data sheet should be updated to include the fixed gain version OPA653. 

    I reviewed different ways to get a high slew rate VFA in this article where a bipolar high transconductance input stage was shown - should have had this OPA659 in those tables.

  • Hi Michael,

    should be added to the datasheet...

    I guess there are lots of custormers (including me) who wonder why the supply current of OPA659 is such high.


  • Hello All,

    Thank you for your reply.

    One of benefit of OPA659, this device has good DC spec even though this is HS OPAMP.

    However, I understood that it trades off these specs against supply current(including Iq).

    We expect you will develop a little bit low Iq with same above good specs.

    Best Regards,


  • Well yes Ryuuichi, the best DC spec in this family is the OPA656B where both the offset and offset drift are screened. Just doesn't have anywhere near the LSBW.