Hello -
Looking for some help with a design using the LMR23630AFDDAR. I used the reference design from WebBench. Cin 10uF, Cvcc 2.2uF, Cboot 100nF, L1 6.8uH, Rfbt 51K, Rfbb 22.1K, Cout 100uF.
Input is varied between 12 - 28Vdc and output is set to 3.3Volts. I have tested from 50mA up to 2Amps. I am getting a very large ripple voltage out at 149kHz. Roughly 0.5Vpk-pk. I have found that the PWM on the switch is not consistent in duty cycle. One pulse will be say 50% duty cycle and then the next pulse is 1% and then this repeats. I always get what I would think to be a 'normal' duty cycle followed by a very low duty cycle pulse. The duty cycle changes with changes to input voltage and load but I always get every other duty cycle pulse to be very short. Output voltage stays in near the 3.3V regulation point.
What should I be looking for?
Thanks
