I am looking to select a couple of data converters for an instrument I am designing. The company I work for has glacial product development life cycles so whatever I parts I pick need to be supported for the long haul (the previous generation of their products was designed in the '90s). I know that Analog Devices is buying Linear Tech which doesn't give me warm fuzzies about any part in either companies portfolio right at the minute. Don't force me to go to TI for this now.
ADC 1: One channel, 18 bit, high DC precision, 100 to 250 KHz sample rate, differential inputs, and a SPI interface. A SAR is what I am looking for. The SAR we most recently used was the AD7691 and we found it's performance acceptable. However, I really don't want to base a new family of products on a part that might be obsolete in 3 years.
ADC2: One channel, 24 bit, high DC precision, ~10 Hz output rate, differential inputs, and a SPI interface.. This will just about have to be a delta-sigma part.
I am also looking for 16 bit voltage output DAC as well. SPI, +/-10V, 10 uS settling time or better. The AD5761R looks interesting, but again longevity is a key characteristic more so than cost.
Let me know if anybody has any insight into what Analog Devices is planning to do with their and Linear Tech's portfolio of parts.
for ADC1 I can recommend to you one of the latest in the ADIs SAR ADC portfolio, the AD4003 which I think fit the specification you've mentioned above.
For ADC2 you can check the AD7789 or AD7791(on chip buffer). You may also try to have a parametric search in the ADI website, you can refer to the link http://www.analog.com/en/parametricsearch/11007#/p1746=16.6|1000000&p3062=1&p193=24&p4364=Sigma-Delta.
Are you using these parts in a single system or each has different application? If there would be a way we can grasp your application, we could help you find or filter some parts for specific application or some circuit note or application notes for reference that are available.