Hi,
You are asking us to "specify" something. Interesting.
All we know is 2..6mV and 0..5V. What else can we specify?
I'd say at least 95% of all OPAMPs are able to amplify a 2..6mV signal to a 0..5V signal.
Really. YOU have to specify:
* signal frequency range
* power supply voltage(s)
* allowed current consumption
* signal source impedance
* expected DC accuracy
* expected noise
* signal waveform
* allowed distortion
* settling time
* output drive current / load impedance
...
After these informations you automatically find out if a usual OPAMP will do, or you need an InstrumentationAmp.
Next time,
* please take any OPAMP datasheet and go through the specification table step by step and decide your application's limits.
* and/or go to any online Opamp selection guide and input your specifications.
*******
Examples (all can be 2..6mV to 0..5V)
* if you want to amplify low frequency signals (temperature, weight) you are interested in DC performance (low offset error)
* if you want to amplify audio signal, you maybe don't care about offset, but low noise and low distortion
* if you build a handheld measurement device you are interested in low power consumption
* if you want to measure current signal (via shunt) of a 1MHz SMPS, you are interested in fast settling time
Klaus