LM25085: Current oscillation

Part Number:LM25085

Hi Team

I have seen a current oscillation while using the LM25085.

Input voltage 17V ~ 20V Output 500mA load is applied.

I added capacitors to GND in parallel between R37 and Q2 and the oscillation disappeared.

Vin's bypass capacitor looks away from the pin. This is supposed to be a reinforced effect.

If yes, please explain in detail why this is happening.

Thanks,

Taemin