Fellow humans:
I need a voltage reference with Rs about 1 ohms or less. This is to drive a simple Instrumentation Amplifier using a general purpose FET op-amp. I need to use a simple IA because their will be four of them and space and cost are factors. A simple IA is affected by the Rs in the two legs. So, to reduce gain errors I need a reference with low Rs to match the Rs of the leg I am measuring.
My question is, can I simply use an LT1004-1.2 straight into my FET IA + input through its 16.5k resistor, (I need gain in my IA their is a FB r as well) or should I buffer it with a unity gain op-amp THEN into my IA ? This is all at DC, AC behavior is not really important. Thank you for your help.
I need a voltage reference with Rs about 1 ohms or less. This is to drive a simple Instrumentation Amplifier using a general purpose FET op-amp. I need to use a simple IA because their will be four of them and space and cost are factors. A simple IA is affected by the Rs in the two legs. So, to reduce gain errors I need a reference with low Rs to match the Rs of the leg I am measuring.
My question is, can I simply use an LT1004-1.2 straight into my FET IA + input through its 16.5k resistor, (I need gain in my IA their is a FB r as well) or should I buffer it with a unity gain op-amp THEN into my IA ? This is all at DC, AC behavior is not really important. Thank you for your help.
If you needed even lower noise, an RC filter on the reference, followed by a buffer, would work.
A shunt capacitor alone wouldn't do enough.
Yeah, if the source impeadance is 1 Ohm, it would need a really huge cap to knock down the noise. But, the noise from this device is already low enough for my needs. I just need a really low Rs to avoid major gain errors. I MIGHT put a build out resistor in the line to match the other input but I have to look into that.
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