ADS1256: ADS1256 CLKIN duty cycle

Niclas Arndt

Part Number: ADS1256
Other Parts Discussed in Thread: ADS1255

Hi,

I'm considering clocking the ADS1256 from a PWM in an MCU running at 120 MHz. This means that the non-decimal frequencies I can generate are 7.5 MHz (PWM period 16), 8.0 MHz (period 15), or 10.0 MHz (period 12).

Of these the 8.0 MHz frequency would be preferable over 7.5 MHz (for unrelated reasons), but PWM period 15 would mean a duty cycle of 7/15 or 8/15. Would this be a problem for the ADS1256? I can't find any information about this in the datasheet.

Best regards

Niclas

over 3 years ago

0 Bryan Lizon86 over 3 years ago

TI__Mastermind 35141 points

Hi Niclas,

Actually, this question has already been answered, see here: https://e2e.ti.com/support/data-converters/f/73/t/771246?ADS1255-SPI-SCLK-duty-cycle-specification

From this post, the recommendation is 40% min, 60% max, 50% nom

-Bryan

0 Niclas Arndt over 3 years ago in reply to Bryan Lizon86

Intellectual 425 points

Hi Bryan,

Thanks. I should have done a proper search.

Best regards

Niclas

0 Bryan Lizon86 over 3 years ago in reply to Niclas Arndt

TI__Mastermind 35141 points

Hi Niclas,

No worries, I will admit that using the e2e internal search is a bit of a challenge.

I usually go to google and enter "site: e2e.ti.com ______" into the search bar. For example, I used "site: e2e.ti.com ads1255 duty cycle" and this answer came up. I initially searched for "ADS1256" instead of "ADS1255" however, and this answer did not come up since I guess google is not smart enough to know that ADS1256 and ADS1255 are so closely related. So it's not foolproof, but it usually works pretty well.

I am working on getting back to you on your other questions. That may take some time.

-Bryan

Data converters

Data converters forum

ADS1256: ADS1256 CLKIN duty cycle