Hello, we have recently developed a prototype board that include an INA821 used as DC amplifier with gain 500, We misread the datasheet and we thought that the Vcm was +/- 2V around the supply voltages (-5V / +33V) : 
We need a simple DC amplifier that amplify by 500 a single ended signal (0mV-60mV)
Is there any drop in replacement available for our purpose?
Godziller,
The maximum supply voltage of INA821 is 36V so with the negative supply at -5V, the highest positive supply you may use is 31V (not 33V).
Doing so, allows in the gain of 500 input voltage range from 0 to 23.6mV - see below.
Changing the supplies to -14V and 22V would allow in G=500 input voltage up to 47mV - see below.
while using -5V and 12V in gain of 250 will input voltage up to 47mV - see below.
You will ran into similar problem with all three-amps instrumentation amplifiers and for this reason you should download Analog Engineer's Calculator I used above to assist you in finding acceptable configuration. Please click on the following link for the download it: https://www.ti.com/tool/ANALOG-ENGINEER-CALC
You may use any precision op amp with input common-mode including negative rail, like OPA187, to satisfy your requirements - see below.
Keep in mind, however, that no op amp (even those called output rail-to-rail) can truly swing all the way to its rails. This means that the actual output may only be linear from 0.1V to 32.9V resulting in valid input from 0.2mV to 65.8mV
