Masanori-san, The calibration timing for the ADS114S08 is a little more complicated than in the ADS1248 . However, it can be calculated from the conversion time of the device. Calibration time length is dependent on the data rate, the filter type, and the setting of CAL_SAMP[1:0] (as the number of samples used for calibration). The amount of time for calibration is similar to the amount of time it takes to get the number of data reads as in CAL_SAMP[1:0] (plus a small amount of time required to capture the OSC or FSC register value). As an example, lets say that you have a data rate of 20SPS, and CAL_SAMP set to 10b (8 samples). For any calibration, you will need 8 samples to determine the calibration coeffiecient. If you are using the low latency filter, then use Table 13 to determine how long it takes to get 8 samples. At 20SPS, it will take 56.504ms + 7 * (50ms). This is about 406.5ms. For an offset calibration, add on another 8 tmod periods, for a gain calibration, add another 24 tmod periods. If you are using the sinc3 filter, then you need a bit extra time so that the ADC allows the measurement to settle. The calculation uses Table 15 for the conversion time. For the same 8 samples for CAL_SAMP 10b, 20SPS will take 150.254 + 7*(50ms) or about 500.3ms. Again, for an offset calibration, add on another 8 tmod periods, for a gain calibration, add another 24 tmod periods. Joseph Wu
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