ZHCSJS8 May 2019 ADS7138
ADVANCE INFORMATION for pre-production products; subject to change without notice.
Figure 134 shows a board layout example for the ADS7138. Avoid crossing digital lines with the analog signal path and keep the analog input signals and the AVDD supply away from noise sources.
Use 1-µF ceramic bypass capacitors in close proximity to the analog (AVDD) and digital (DVDD) power-supply pins. Avoid placing vias between the AVDD and DVDD pins and the bypass capacitors. Connect the GND pin to the ground plane using short, low-impedance paths. The AVDD supply voltage also functions as the reference voltage for the ADS7138. Place the decoupling capacitor (CREF) for AVDD close to the device AVDD and GND pins and connect CREF to the device pins with thick copper tracks.