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Hi all,
For unipolar mode (AVDD=5V, AVSS=0V, VREFP=5V, VREFN=0V), ADS1282 full-scale input voltage is from 0V to 2.5V. Am i right?
Also data code is range from 00000000h to 7FFFFFFFh for FIR filter. Am i right?
Most of data in the datasheet is according to unipolar mode. Thus, i'm not sure about this subject.
Regards,
Eren
Sorry for mistake. *most of data in the datasheet is according to bipolar mode
Hi Eren,
The difference in data formatting for FIR vs SINC filter mode is a little confusing, let me try to clarify...
First off, the supply mode (unipolar or bipolar) will have no effect on the data format. However, how you configure the supplies will affect the ADC's common-mode input range. In other words, the AVDD and AVSS supply voltages will put a restriction on the absolute voltages that can be applied to the analog input pins.
The output data is not related to the absolute input voltages, but rather the differential voltage between AINP and AINN. The maximum differential voltage that can be measured by the ADC is +/- (Vref / [2 * PGA]). Therefore, for a 5V reference and PGA = 1 V/V, the ADS1282 can measure differential inputs within +/- (5V / [2 * 1V/V]) = +/- 2.5V.
Where things get to be confusing is the difference between FIR filter mode and SINC filter mode. In both modes you'll clock out a 32-bit word and get 31-bit, two's complement signed-data, however here is the difference...
NOTE: At the fastest SINC filter data rates you may only have enough time to clock out 16- out of the total 32-bits of data, so you will need to stop clocking out data after the first two bytes.
I hope that explanation helps. Let me know if you have any additional questions!
Best regards,
Chris