BQ24210: bq24210 output unstable

Part Number:BQ24210

Hi, 

I am using bq24210 on my custom board to charge the Li-ion battery using the Solar panel.

I am applying variable DC power from bench power supply (Just to simulate Solar panel input) to bq24210 input & measuring o/p voltage on BAT pin. I have configured charger in battery tracking mode & set charge current to 0.8A.

Following are the observations,

1. Charger chip output oscillates at freq 18Hz between 3.8 to 4.2V levels during no-load condition. See the attached image.
2. The same output voltage oscillation appeared when connected 25mA load at the output, BAT pin.

What could be the cause of this issue?

Appreciate early responses.

Thanks,

Ritesh