7660 clock source?

[egasimus]

I want to use a 7662 (7660 analogue) to get -9V from a 9V battery. However, the oscillator operates at 10kHz by default, which I fear will cause some audible whine in the circuit. I read in the chip's datasheet that the internal clock can be overridden by an external clock source. So what's the oscillator with lowest part count/board space/cost that can work in this application?

[frequencycentral]

Easier to just use a ICL7660S or MAX1044, both of which have a frequency boost feature.

[Hides-His-Eyes]

It's an interesting question though; could you run the oscillator at say, 100k with nothing more than an additional op-amp?

[egasimus]

Easier using - perhaps, easier obtaining - certainly not. The only thing I could find anywhere was the ICL7662CPA.

[Hides-His-Eyes]

op-amp or CMOS clocks would probably both work, similar parts count...

[egasimus]

Hmm, what about a transistor-based RC oscillator? I'd prefer not to add another opamp just for this.

[Thomeeque]

I want to use a 7662 (7660 analogue)

Which one exactly? I have found Microchip TC7662A datasheet and OSC pin there is not input for external oscillator - it only allows to add parallel capacitor to internal to lower the frequency:

The on-board oscillator
operates at a nominal frequency of 12kHz. Operation
below 12kHz (for lower supply current applications) is
also possible by connecting an external capacitor from
OSC to ground.

Maybe you could "hack" it via this pin somehow, but I don't know..

T.

[egasimus]

It's an ICL7662CPA. The datasheet says that the oscillator can be overridden by a higher frequency one through the clock pin - I just wonder if any sort of oscillator would work, or should it be a specific waveform, duty cycle, implementation? (As I said, I'm reluctant to add a 8-pin IC to the layout and would prefer to go with transistors, but it's no big deal)

[Hides-His-Eyes]

I suppose this might work:

http://www.technologystudent.com/elec1/dual1.htm

but I have no idea if it'll work at such a high frequency. Whereas an op-amp or CMOS clock gen will definitely be fine at those frequencies.