- By using TLV2371, I can bias at 2.5V and use from Gnd to +5V, right?
Right.
- Whats the maximum gain of TLV2371? I need maximum gain of 200 either with single op-amp (like lm386) or dual op amp (like lm 358)?
I think you are confusing an "op amp" with an "audio amplifier". Devices like the LM386 are pre-built audio amplifiers with a certain gain. A regular op-amp like the TLV2371 has to be designed in a certain configuration (inverting amplifier, non-inverting amplifier, etc.) and you select the gain by your choice of resistors in the circuit. Here is a good place to start reading:
The LM6142 should work too, but we can't comment on whether or not it's a good choice unless you have more specifications. What's wrong with the TLV2371? It's a lot cheaper than the LM6142 (5 times cheaper by my estimate).
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