AnsweredAssumed Answered

AD8219 offset vs common-mode voltage

Question asked by sam.shyu@wpi-group.com on Jul 30, 2014
Latest reply on Aug 10, 2014 by Emman.A

Dear Sir,

 

We test the offset of  AD8219  as below:

AD8219 VS = +5V or connect with VCM

       NO Load  (0A at +VBAT)

                 1. VCM = 0V,  AD8219 VOUT = 3.7mV

                 2. VCM = 10V, AD8219 VOUT = 4.55mV

                 3. VCM = 20V, AD8219 VOUT = 6.9mV

                 4. VCM = 30V, AD8219VOUT = 9.85mV

      1A Load at +VBAT

                 1. VCM = 0V,

                 2. VCM= 10V, AD8219 VOUT = 63.8mV

                 3. VCM = 20V, AD8219 VOUT = 66.9mV

                 4. VCM = 30V, AD8219 VOUT = 69.9mV

 

       Why AD8219 VOUT offset will increase with the VCM increases? (IN+ / IN1 direct short the offset AD8219 VOUT same increase with the VCM increases)?

 

AD8219 schematic.jpg

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