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In the most part of tutorials I see they use INA125 as the instrumentation amplifier for load cells.

Is it ok to use another cheaper amplifier as the AD8237? Or is there a specification or peculiarity that I need to consider?

I want to use a gain of 1000 (as the load cell rated output is 1mV/V) and the power supply can be 3.3V or 5V (I am still deciding). It is possible to get an output equals to the power supply with these amplifiers?

Thanks

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    \$\begingroup\$ It is possible to get an output equals to the power supply with these amplifiers? - Look for 'rail-to-rail' on the data sheet \$\endgroup\$ – Will Apr 15 '14 at 10:48
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Well, with a single supply, you should look toward rail to rail Instrumentation amps like the ad623. A gain of 1000 all at the IA might have bandwidth concerns, so keep an eye on the data sheet. Gain at the IA stage actually improves CMRR, but if it cuts bandwidth too much, give it a more modest gain and add a second gain stage with an op amp.

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  • \$\begingroup\$ Thanks for your reply, If I understood well then I am good to go with the AD8237, because it is a Rail-to-rail input and output, it has a Minimum CMRR: 106 dB which give me an error of +-50uV in the output with 10V of common-mode and my application with the load cells is low frequency. \$\endgroup\$ – koike Apr 15 '14 at 18:19

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