ZHCSN80 july 2023 ADS131B24-Q1
PRODUCTION DATA
The fault indication response time to an overcurrent event depends on the amount of overshoot of the input signal beyond the comparator threshold. The reason for this dependency is the settling time of the sinc3 filter that is used for the digital comparator function.
Figure 9-14 and Figure 9-15 show two examples for the OCCA fault indication behavior with OCCA_NUM[4:0] = 00000b, that is only one conversion must exceed the threshold to trigger a fault. In Figure 9-14 the comparator triggers in less than 64/fMOD (= 15.6 μs when using fMCLK = 8.192 MHz) because the sinc3 filter already settles to a value above the set high threshold in one conversion due to the large overshoot beyond the high threshold on the input signal. Figure 9-15 shows a worst case scenario where the sinc3 filter needs even four conversion periods to settle to a value above the set high threshold because the input signal barely exceeds the high threshold and the overcurrent event happens in the middle of a fast filter conversion cycle.
The response time changes when global-chop mode of ADC1y is enabled and ADC1y is converting. See the Global-Chop ModeOvercurrent Indication Response Time in Global-Chop ModeGlobal-Chop Mode section for details.