Re: Choosing voltage opamp

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#2055

From: PeteS
Date: Sat, 23 Sep 2006 18:47

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Vitaliy wrote:
> Hello,
>
> I'm looking to add the 2nd stage to photodiode transimpedance
> amplifier. All I want to achieve by 2nd stage is voltage gain and
> capability to drive 50 Ohm loads. The first stage is OPA657.
>
> 1) a) Given power supply for opamp +-5V, should I select the opamp that
> has Io,max=>200mA. I do expect Vpeak-to-peak,output to be 10V.
>    b) Is that output current achievable only at maximum supply voltage,
> or as long as
>
> 2) I need to get an opamp with maximum input impedance (well, anything
> >=1MOhm will do it). Should I get the one with JFET-input? Or any voltage amplifier will do the job?
>
> 3) What is Iq per channel(Max)(mA)?
>
> 4) Would SOIC packaging be better in general? Given that pcb layout is
> optimized.
>
> Thanks in advance,
> Vitaliy

All of the usual suspects (National, TI [including Burr-Brown], Linear
tech, AD and others) make devices specifically designed to drive 50 ohm
loads.

Check out the websites and use the parametric search function and
specify 50 ohm load and then choose a suitable device. We don't know
what type of load that is beyond 50 ohm, so the above is the only
advice I can give.

Cheers

PeteS

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From: "PeteS" <PeterSmith1954@googlemail.com>
Newsgroups: sci.electronics.design,sci.electronics.basics,aus.electronics
Subject: Re: Choosing voltage opamp
Date: 23 Sep 2006 11:47:21 -0700
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