10.3 Do's and Don'ts
- Do partition the analog, digital, and power-supply circuitry into separate sections on the PCB.
- Do use a single ground plane for analog and digital grounds.
- Do place the analog components close to the ADC pins using short, direct connections.
- Do keep the SCLK pin free of glitches and noise.
- Do verify that the analog input voltages are within the specified PGA input voltage range under all input conditions.
- Do float unused analog input pins to minimize input leakage current on all other analog inputs. Connecting unused pins to AVDD is the next best option.
- Do provide current limiting to the analog inputs in case overvoltage faults occur.
- Do use a low-dropout linear regulator (LDO) to reduce ripple voltage generated by switch-mode power supplies. Reducing ripple is especially important for AVDD where the supply noise can affect the performance.
- Don't cross analog and digital signals.
- Don't allow the analog and digital power supply voltages to exceed 5.5 V under any condition, including during power-up and power-down.
Figure 117 shows the do's and don'ts of the ADC circuit connections.
Figure 117. Do's and Don'ts Circuit Connections