We would like to use the AD7621 or AD7641 in our project.
Does the AD7621 can work with SPI interface in 1.25, 2 and 3 MSPS?
Does the AD7641 can work with 16 bit and SPI interface in 1.5 and 2 MSPS?
The AD7621 can only use the full 3MSPS with the master read during convert mode
serial interface. Using the slave mode will have issues since digital activity
will run into more than 1/2 of the conversion cycle unless you can live with
some slight performance degradation, namely INL and THD.
The AD7641 can use the 2MSPS in serial slave mode since there is 115ns of
acquisition time which can be used to read some of the bits and then the
remaining bits can be read safely into 1/2 of the 385ns conversion time.