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Question asked by decaf14 on Jul 24, 2018
Latest reply on Jul 26, 2018 by Emman.A



I'm trying to perform a very simple LtSPICE simulation using the AD8421. I'm running into a weird issue that I can't figure out. The gain of the system is basically non existent. I've read that analog devices cannot confirm the accuracy of their products in LtSPICE. What does this mean? Does the circuit setup below look correct for a gain of 10? I've tried both the 8421 online model (shown below) and the model built into the "opamps"component section of LtSPICE. 


The voltage was measured at the output. The gain of the system is negative. For anyone not familiar with LtSPICE input syntax, the input voltage here is 0.1V P-P at a DC offset of zero and frequency of 200. I was thinking since the positive terminal amplifies in reference to the grounded negative terminal, the P-P voltage should increase by 10 at the output, and thus be 1V P-P.


NOTE I did not use the circuit on the left to take out an extra troubleshooting step. This circuit is per the datasheet of the AD8421 for properly creating a reference voltage.