Hello..
One of my customer is working on ADS1278 & they want the data for Group- delay (Tgd) and Settling time (tst) of ADS1278.
Can somebody confirm, whether all the calculations are ok? Before submitting to customer I want to make sure the calculations are ok. Pls. find excel sheet.
Mitesh
Hello Mitesh,
I checked the calculations, and they all look correct. I noticed that you duplicated the High-Speed 32.768MHz clock row. I think you may want to change one of these to 37MHz.
Please note that to operate with a CLK frequency greater than 27MHz, only Frame-Sync mode can be used (SPI is not supported). In addition, for CLK frequency greater than 32.768MHz, DVDD supply must be in the range of 2V to 2.2V and the maximum reference voltage is 2.1V.
Also, in the last column, you are adding the group delay and the settling time. I am not sure that this is needed; the group delay is approximately the settling time needed to reach 50% of the final value, as shown in the below picture. If you are interested in total settling time for a step input, then it is just the settling time by itself, and not the sum of the group delay and settling time.
Regards,
Keith Nicholas
Precision ADC Applications
