> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of Dumitru Stama
> Sent: 02 April 2012 15:06
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] rail-to-rail LM358N alternative
>=20
> > Depends if you need rail-to-rail input AND output, what bandwidth,
> > etc.
> >
> > For example, OPA2171 is only $1.85 in small quantities, is R-R out,
> > and the input CM range includes the lower rail, but only within 2V of
> the
> > upper rail.
>=20
> I need it to amplify the voltage drop over a sense resistor.
> If the sense resistor is 0.1 ohms and i have a 100mA current through
> it then the voltage across it will be something like 0.01V. I need the
> opamp to amplify it 15 times and output 150mV.
> I need its output to be as close as it can to GND, the +24V supply is
> just a requirement for this circuit, the voltages will never reach
> that value.

Have you tried loading the output the output of LM358 with a resistor to gr=
ound? (e.g. ~10k).  They will typically get within ~5mv of ground which wil=
l be significantly exceeded by potential input offset voltage issues in thi=
s particular case.

Cheers

Mike

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