DAC7718 output response time

Hi Na Na,

na na78 said:

Can you calculate a spent time from the time starting control with SPI to the time its to be reflected as an output?

In DACs the time spent between the SPI update signal and the output starting to ramp up, is called the "dead time". This does not include the entire SPI frame as the timing can change drastically depending on the SCLK frequency.

You can find more information in this blog DAC Essentials: Understanding your DAC's speed limit. Let me know if you have any questions regarding its explanation.

It explains that the "dead time" is included in the settling time specification of the DAC.

na na78 said:

We want to know what kind of elements should be considered. (SPI access speed, slew rate, setting time and so on?)

How fast does depend on these. If you can share some more details of your application I can probably calculate these for you.

How fast you can update the DAC depends on:

SPI_frame_time + DAC_update_delay + Settling_time

The DAC_update_delay depends on the mode that you deside to use to update the DAC. You can look at page 43 of the datasheet to read about a few ways to update the DAC output.

If you have any more questions let me know and I should be able to help you out.