Hi team,
My customer is using UC2861. In our datasheet, it recommends that 5V pin should connect to GND with a 0.1uF cap.
However, customer found that, during power up process, the 5V waveform has some undershoot. Please see below picture. CH1=Aout. CH2=Bout. CH3=5V pin. CH4=VCC pin. As you could see, during power up, 5V pin undershoot reaches ~4V which makes the device shutdown due to 5V UVLO(CH1 and CH2 stop output).
Then customer added an extra 1uF cap on 5V pin. Then the issue is gone. Please see below waveform. During power up, 5V pin undershoot is smaller and the device can boot successfully. So could you please advice what is the max cap value that uc2861 5V pin can connect to? Datasheet recommends only 0.1uF so is this 0.1uF+1uF also OK? Thanks.
Best regards,
Wayne
