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LM4819: LM4819 Pop noise issue at power down.

Part Number: LM4819


My customer have the pop noise issue when power down timing.

Output waveforms and schematics are below, 

The condition2 is little bit improved the pop noise than conditon1.  However. customer have to decrease the pop noise more.

Could you please give me your advice for improvement method?

Condition1:  Ci=0.22uF, Ri=47kΩ, Cb=1uF

(Ch1:VDD(5V)  Ch3:Vo2+ Ch4:Vo1-  Math:Ch3-Ch4)

Condition2:  Ci=0.1uF, Ri=100kΩ, Cb=1uF

(Ch1:VDD(5V)  Ch3:Vo2+ Ch4:Vo1-  Math:Ch3-Ch4)

Schematics (same circuit in datasheet)