AnsweredAssumed Answered

Comparing instrumentation amplifiers

Question asked by bonpin on Jun 27, 2018
Latest reply on Jun 28, 2018 by Emman.A

We're working on a maximally sensitive strain gauge bridge sensor circuit, and have come across competing instrumentation amplifier architectures from AD for our preamplifier stage. Here are some quotes from their datasheets' general descriptions. For context, our bridge has a maximum output range of +/- 5 uV, and we'd like a bandwidth of DC to 30 kHz, connecting to a 24bit AD7768 ADC.


'Designed to easily and accurately convert variable pressure sensor and strain bridge outputs to a well-defined output voltage range'



'Low voltage noise and low current noise make the AD8422 an ideal choice for measuring a Wheatstone bridge.'



'The AD8429 excels at measuring tiny signals.'


We think an AD8557 would be simplest to implement, but given that the datasheets the top two advocate themselves as being appropriate for bridge circuits, and the third sounds like it has the best noise and bandwidth properties (and thus should be the most appropriate), how would we compare and decide which sort of chip is best?

Thank you