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Original question:

LMH6622: Function generator

LMH6622: LMH6622

Vinay Kattela
Prodigy 20 points
Part Number: LMH6622
Other Parts Discussed in Thread: OPA2863

Hi,

I was looking for an alternate option for  LT6203, it seems the cross reference output from TI weblink shown as LMH6622.

When compared between : LMH6622 is not unity gain stable and that’s required for some of the blocks on the design.  It takes twice the current per amplifier compared to LT6203.  

Also LMH6622 package is bigger due to space constraint.

Do you have any better suggestions that could meet above requirement ?

  • 0
    TI__Prodigy 525 points

    Hi,

    You could consider using the lower power OPA2863. This is a 50 MHz, RRIO, voltage feedback amplifier with 2.7 - 12.6 V supply voltage capability. The unity-gain stable OPA2863 consumes only 700 uA per channel and is offered in a very small 2x2mm RUN-10 dual channel package. 

    The OPA2863 also offers the overload power limit feature to limit the increase in quiescent current in input overdrive conditions, if such condition may happen in your design, and avoid excessive power consumption/dissipation on board should this occur.

    There's another much higher precision trimmed version OPA2863A with max. 95 uV offset and max. 1.2 uV/C drift offered in a 3x3mm dual DSN-10 package.

    Regards,

    Bharat Agrawal

  • 0 in reply to Bharat Agrawal60
    Guru 48395 points

    The OPA2863 looks like a very nice new device. 

    I was looking for lower noise options, really nothing that is also RRIO in the TI product line that I can find. 

    The LMH6622 is spec at a gain of 2, but operates ok at gain of 1. TINA V11 had a model, here is gain of 1 sim. That 1.6dB peaking implies a unity gain phase margin (with 200ohm load) of 52deg. Not too bad really. 

    As per this plot, 

    Here is this file, the LMH6622 was being suggested I am guessing since it was a closer match on input noise, but not RR. I would be guessing the very new OPA2863 is not in the TI cross reference tools. 

    LMH6622 gain of 1.TSC