The datasheet page 28 says:
“For better load transient response, set VREF to a lower value and use a feedback resistor divider to set the final VOUT. In this case, a feed-forward capacitor can be added to sense the VOUT change more quickly.”
I couldn’t find any information regarding the recommended capacitance of the feed-forward capacitor. What value should I use and how it relates with different feedback resistor values? I’m using MPM54304GMN-0001 with output voltages of 1.2 V, 2.5 V, 3.3 V and 5 V.
Hi martin.poder,
Thanks for your question.
Adding in the feed forward capacitor optimizes the transient response, which increases bandwidth and phase margin. The recommended FF cap value to use with this part is 33nF.
Unfortunately, we do not have a formal equation to determine the FF cap value.
However, there is public information on the web that elaborates on how to determine this value. I was able to find the following info: To determine the optimal feed forward capacitor value, find the crossover frequency with an unpopulated feedforward capacitor using transient analysis or a network analyzer. Then select a value that gives you a good compromise between bandwidth improvement and phase margin.
Thanks,
Cindy