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Output of AD8436

Question asked by kotoo@fujiele.co.jp on Oct 8, 2015
Latest reply on Oct 15, 2015 by kotoo@fujiele.co.jp

Please teach me AD8436.

 

I would like to make a simple RMS / DC.

I've created a circuit design similar to that Fig3 of AN1341.

 

CIN has not been placed.

VCC=+5V,

VEE=-5V

CAVG Cap=22uF

IGND is connected to GND

 

I has tested the following.

1.RMS Input=0V(RMS)      =>Output= 0.2mV

2.RMS Input=0.5mV(RMS) =>Output=0.2mV(Not change out put voltage)

3.RMS Input=30V(RMS)    =>Output will vary greatly

4.RMS Input=0V(RMS)     =>Output= 0.4mV

5.RMS Input=0.5mV(RMS)=>Output= 0.5-0.6mV(change out put voltage 0.1-0.2V)

 

It differ output voltage of 2. and 4.

If I change the input voltage from 0V (RMS) to 0.5V (RMS), 2 is no change, but 5 is change.

 

This change is undesirable, please teach me the measures.

 

Thank you.

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