ZHCSJS8 May 2019 ADS7138
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The ADS7138 has two separate power supplies: AVDD and DVDD. The device operates on AVDD; DVDD is used for the interface circuits. For supplies greater than 2.35 V, AVDD and DVDD can be shorted externally if single-supply operation is desired. The AVDD supply also defines the full-scale input range of the device. Decouple the AVDD and DVDD pins individually, as shown in Figure 133, with 1-µF ceramic decoupling capacitors. The minimum capacitor value required for AVDD and DVDD is 200 nF and 20 nF, respectively. If both supplies are powered from the same source, a minimum capacitor value of 220 nF is required for decoupling.