Hi. I have a differential amplfiier here that has an input common range of +/-2.5V (half the supply voltage). I was wondering if I need to clamp the inverting input like in the attached schematic since the transformer's outputs are floating differential outputs (as opposed to the differential outputs that aren't floating from something like an op-amp where the power driving the differential outputs come from the power rails and are therefore inherently have a bounded common-mode range.
I will be clamping at least the non-inverting input for sure since abnormal operating conditions might cause the voltage to exceed the maximum.
1. But I was wondering if I should clamp the non-inverting input to make sure that the common-mode stays within the maximum limits of the amplifier?'
2. Is there any mechanism on the amplifier's differential inputs that would try and pull the common-mode range of a floating differential outputs of a source (the transformer) to within the amp's common mode input range?
3. If there is no such mechanism like in #2 , then I guess I must tie the inverting input to grounds. But if there is, should I still just tie the inverting input to ground? Because if I don't, it seems like the common-mode signal might float away beyond the limits of the amp. If I tied one input to ground it would ensure that the signal would stay within the common mode input range of the amp.
4. And is it pointless to use the amp in differential mode since it's already being fed from a transformer which kind of makes it differential already?
I will be clamping at least the non-inverting input for sure since abnormal operating conditions might cause the voltage to exceed the maximum.
1. But I was wondering if I should clamp the non-inverting input to make sure that the common-mode stays within the maximum limits of the amplifier?'
2. Is there any mechanism on the amplifier's differential inputs that would try and pull the common-mode range of a floating differential outputs of a source (the transformer) to within the amp's common mode input range?
3. If there is no such mechanism like in #2 , then I guess I must tie the inverting input to grounds. But if there is, should I still just tie the inverting input to ground? Because if I don't, it seems like the common-mode signal might float away beyond the limits of the amp. If I tied one input to ground it would ensure that the signal would stay within the common mode input range of the amp.
4. And is it pointless to use the amp in differential mode since it's already being fed from a transformer which kind of makes it differential already?
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