TS3A227E: TS3A227 pop sound on power up

Part Number: TS3A227E

Hi all,

 My customer use TS3A227 in their Lenovo dock project. Lenovo complain about the pop issue when they power up their dock and connect its phone jack to an active speaker: 2 pop sound (maybe near 2KHz frequency) is heard. And we can see there's 2 pulse (5mV DC level) shown on L/R channels. We think that's detection function for 3/4 pole headset. but...

1. There's no pop sound heard by their TS3A225 product.

2. There's no pop sound founded when they connect their amp into jack.

 Is anything we can do to reduce the pop(detect) sound on power up.... And why TS3A225 don't have the sound?

 Thanks for your kindly help.

Best regards,

Gary Teng

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