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ADE7753 Current Input Gain / Full Scale Options

Question asked by dvetter on Mar 10, 2016
Latest reply on Mar 13, 2016 by dvetter

I'm working on a ADE7753 design using a Rogowski Coil for current measurement and an external 2.5V reference for increased stability.  Like most coils this has a relatively low sensitivity of 460uV/A.  That means at my max current of 20A I'm looking at a mere 9.2mV output.


Looking at the datasheet, Rev C, Page 16, Table 5, "Maximum Input Signal Levels for Channel 1" it appears I have two options with regard to provisioning the input range and gain:


Input Range 0.25V -> Gain = 16

Input Range 0.125V -> Gain = 8


Both options allow up to 15.6mV maximum input voltage.


The question I have is, does it matter which option I choose? Is it better to have lower gain and a reduced input range or a higher gain and increased input range?  Does one result in, say, lower noise and therefore greater accuracy?