I am designing microphone preamplifier using MAX4468 (datasheet), but the reference diagram shows output from microphone (microphone input) going to both inverting and non-inverting terminals of the device. (picture attached below). Non-inverting terminal should be connected to ground or both non-inverting and inverting terminal should be given microphone input.
The datasheet describes a point:
The MAX4466/MAX4468 are decompensated for a minimum stable gain of +5V/V.
Does it means that opamp will provide inherent gain of 5, irrespective of feedback resistors.(Page 1 of datasheet)
Best Answer
No, it means that you must not choose resistors that produce a gain of 5 or under or the output signal may go unstable.
No, that's not how this circuit works. As shown it appears fine and will have a gain of about -10 (minus means inverting). The non-inverting pin connects to a mid-rail voltage to properly bias the op-amp when using a single supply.