hey hi ! i have used LMC7660 to get a bipolar 9v supply...and i am getting a buzz since the circuit gain is quite high(distortion ckt)...i am suspecting the 7660 for the buzz since the frequency of the buzz is aroundthe same as the clock speed of the 7660 ..... is there any way i can eliminate without replacing th e7660 byt a better charge pump..like MAx 1044 or something?!?!
HELP :)
Have you tried disabling the charge pump and substituting external power to isolate the actual source of the noise?
The LMC7660 data sheet seems to imply that you can LOWER the internal clock rate, but that raises output impedance and ripple, and does nothing to eliminate your audible noise. Or you can go with an external clock.
Might be better off updating to the MAX1044 or one of it's peers. (the benefit being a pin-selectable higher internal clock rate, above audio spectrum.)