Hi
Out customer evaluates LM3485 on their board. However the frequency increased to almost the maximum frequency(950kHz) when it's power on.
(Vin =27V, Vo=12V, Io=2A, Rfb: R1=8.76kohm, R2=1kohm, Cff=100pF)
However when Vin is changed to 20V the frequency is 66kHz. Also if the Cff is removed, the frequency is 60kHz at Vin=27V.
I do not understand why this phenomenon is happen.
1. Can we remove the Cff? (Please let me know if there is any concerns without Cff)
2. Should we increase the Rfb more than now?
Regards,
Koji Hamamoto
