Question
We are planning to use the AD7091R in a mobile low power distance measurement
device. We need a data throughput of 1MSMP/S. My question is if it is possible
to readout the data by SPI during a conversion. At the datasheets there are
only examples in which the data a readout by SPI after a conversion. This means
that I need a very high SPI clock when I want to use the ADC at 1MSPS.
Answer
After testing an eval board, the answer to the question is yes. In fact this is
how it's done on the SDZ eval board as the SDP is limited with maximum clock
speed.
The caveat here is that tQUIET of 50ns min is violated when doing this. The
part was never evaluated/tested for this condition, and we can't guarantee
specified performance when running the part in this manner.
It is also essential that any reading of data from the SDO line is completed
before EOC. The output register is updated with the next result at EOC.