I need a amplifier which can reject 2MHz common model signal.But in reviewing In-Amp datasheets, only CMRR within 1MHz is provided and 2MHz CMRR is not supposed to be very high. Any recommendations on chip selection? or other solutions?
I will need to check our part list to find out whether we have a single solution for your requirement. We do have another solution - a reference design for a high bandwidth instrumentation amplifier, which likely has better CMRR at higher frequencies. You can check it out at this link. You might also be able to just implement a common-mode filter to reject this. It all depends on how this 2MHz signal is being applied in your circuit. Will your input signal be riding on the 2MHz common-mode, or are you just concerned about some environmental noise? If you could tell me more about this and about your application, I will be able to give you a better recommendation.
Thanks for you reply.
The 2MHz common-mode signal is directly applied on the input and the signal is about 1 to 4 V.
More than 65 dB CMRR is preferred BTW, THX
You can try checking out the AD8130, it has very high common mode rejection at high frequencies and can be used in high frequency in amp applications. The common mode rejection over frequency performance is given in the graph below:
Do you think this amplifier will satisfy your needs? What will your application be?
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