ZHCSIK6D November 2017 – June 2024 ADS8166 , ADS8167 , ADS8168
PRODUCTION DATA
The ADS816x has a precision, low-drift reference internal to the device. The device features an internal reference source with a nominal output value of 4.096V. On power-up, the internal reference is enabled by default. Place a minimum 1µF decoupling capacitor, as illustrated in Figure 6-6, between the REFIO and REFM pins.
Figure 6-7 shows the connections for using the device with an external reference. Use a reference without a low-impedance output buffer because the input leakage current of the internal reference buffer is less than 1μA.
For the minimum ADC input offset error (VOS), set the REF_SEL[2:0] bits to the value closest to VREF (see the OFST_CAL register). Set the REF_OFST[4:0] (see the REF_MRG1 register) bits to add or subtract an intentional offset voltage as described in Table 7-14. Short the two REFP pins externally. Short the REFM pin to GND externally. Place a decoupling capacitor CREFP between the REFP and the REFM pins as close to the device as possible; see the Layout section for layout recommendations.