I'm working on an audio project that I hope to be able to turn in to a product for sale. As part of it I want to create some LED bargraph level meters with features that can't be implemented with a simple resistance ladder and stack of comparators (e.g. with LM3915 chips).
I have been looking (so far unsuccessfully) for a chip that has a 12-bit ADC that can run at at least 40K samples/second, a microprocessor that can compute which LEDs I want turned on under various conditions (to show "average", "peak", etc.), can control 16 LEDs (the bargraph), and is dirt cheap. ADC performance (noise, ENOB, etc.) doesn't have to be particularly good. I'll need four meters per device, so instead of one chip per meter I could use a multi-input ADC, and control four LED-driver chips over a serial bus.
Can anyone point me to a chip or chip family that might suit my needs? Thank you.