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AD8436 DC Voltages

Question asked by AnalogLover on Feb 17, 2015
Latest reply on Feb 18, 2015 by AnalogLover

I am using an AD8436 to attempt to convert AC voltages to an RMS equivalent as well as pass DC values through the circuit unaffected. My setup is the same as Figure 40 on page 15 of the datasheet (http://www.analog.com/media/en/technical-documentation/data-sheets/AD8436.pdf) except I do not have the 0.47 uF capacitor on pin 5. After testing the device, I noticed that it works very well for AC voltages with a 2.5 V DC offset, however when I attempt to pass a DC voltage through the circuit I get almost 0 voltage.

 

Is my setup somehow AC coupled? If so, is there a way to configure the AD8436 so that it will give the RMS equivalent of AC voltages and pass DC voltages?

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