I bumped into an interesting device ADuC841. It seems to be a microcontroller with extensive ADC/DAC peripherals. Since I am not experienced and did not have to use combination of ADCs and DACs, going though the datasheet does not give me a good insight about the device. Did anyone use it before? I wish someone could provide some examples where the use of this device would be more efficient than using other uCs and ADCs. Although, this device costs about $20 a piece, but I would rather want to know the technical advantages.
The name is a clue. "Microconverter". You can consider this an ADC/DAC with a microcontroller peripheral attached rather than a microcontroller with peripherals. The (semiconductor) process used is more optimized for precision analog than trying to fit analog bits into a digital process and ending up with mediocre analog performance. For example, the reference has a tempco of 15ppm/K (typical) and is accurate to +/-0.4% maximum. Not great numbers, but better than most of (say) Microchip's offerings. That said, this is a very old chip (over a decade, IIRC) and each year the cheap/high volume ones tend to get a bit better.
So the main difference is the performance of the analog bits- reference, ADC and DAC will be closer to that of similar discrete devices (they're made by a company known for analog prowess).
You can also get models with "24-bit" ADCs, and an ARM core.
The advantage of having several chips combined into one are less board space, easier to get going, less parts on the BOM. Disadvantages are that the cost will probably end up higher, and the performance lower than a solution designed with separate chips. If the chip gets discontinued and you've designed a product (or an entire product line) around the chips, you may have bigger problems than if you went the other way.