MCP73833 Charger IC not reaching End-of-charge

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1

Hi,

I recently designed a custom PCB that is powered by a 4.2V LiPo battery. I’m using MCP73833 as the charge management IC. However, I observed an odd behavior from the IC when the charge cycle is complete. The charging status LED goes into fast dimmed blinks, and the IC never turns on the charge complete status LED. When I probe the battery voltage on the oscilloscope, I see it going between 4.8V and 4.2V in a sawtooth wave pattern. Please keep in mind that the PCB is not powered yet, the battery is being charged only. I have attached the schematics for the charger.

This is the IC: https://www.digikey.com/product-detail/ … ND/1223175

Please help!

2

You failed to follow the design recommendations in the data sheet.

At least one problem is that the bypass capacitors (Cout in particular) are too small.