Look on the manufacturer's websites for "High Side Current Sense
Amplifiers" or "Current Monitor" amplifiers.

Almost all the analog suppliers make them, they are typically low cost, low
power differential amplifiers with high CMV specifications, low input
offset voltage and moderate to high gain. Many allow the gain to be set
with a single resistor. A gain of 15 as you require is right in the middle
of the range most of them offer. They're made to do exactly what you're
looking for.

Matt Pobursky
Maximum Performance Systems


On Mon, 2 Apr 2012 17:05:48 +0300, Dumitru Stama wrote:
>> 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.
>>
>
> 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.

--=20
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