Hi guys
I am choosing DAC for 100kHz sinewave generation (several volts),and I want waveform to be smooth as much as possible in time domain(meaning that there are suitable points)
My personal optinion to choose a suitable precision DAC is:
- Rlew rate of DAC, for 100kHz signal with ±1V amplitude, the IC's slew rate should be 10 times greater than 10×1.26V/us = 12.6V/us
- Bandwidth of DAC
- Sampling rate of DAC
Differenet from high speed DAC, Precision DAC (Voltage output DAC, or Multiplying DAC) doesn't list sampling rate of DAC, AC performance and MSPS (mega sample per second), they only list SPI clock. And AD5791R's datasheet (AD5791 datasheet.pdf) only lists 1kHz AC performance so I don't whether they can produce 100kHz.
My question is
（1）Can I estimate the maximum sampling rate of DAC by SPI clock? For example, Maximum SPI clock of AD5791R is 35MHz, from datasheet, SCLK cycle time is 28 ns, for one update, 24 SCLK cycles so maximum update rate is 1/(24×28ns)=1.48MHz (actual update rate must be lower than this, so 14.8 points for 100kHz?). This calculation I follow ADI Precision DAC advance
(2) Second question is, why AD5791R and AD5544 have different SCLK high time and SCLK low time, they all follows SPI protocol. That leads to: although AD5544 can operate under SPI 50MHz, but SCLK cycle time is much greater than AD5791R.
SCLK high time/low time for AD5791R
SCLK high time/low time for AD5544
