Overview

nRF5340 Product Specification

The ADC supports up to eight external analog input channels. It can be operated in One-shot mode with sampling under software control, or Continuous mode with a programmable sampling rate.

The analog inputs can be configured as eight single-ended inputs, four differential inputs, or a combination of these. Each channel can be configured to select one of the following:
  • AIN0 to AIN7 pins
  • VDD pin
  • VDDHDIV5 (through VDDH pin)
Channels can be sampled individually in One-shot or Continuous sampling modes. Using Scan mode, multiple channels can be sampled in sequence. Channels can also be oversampled to improve noise performance.
Figure 1. Simplified ADC block diagram

Simplified ADC block diagram

Internally, the ADC is always a differential analog-to-digital converter, but by default it is configured with single-ended input SE in the MODE field of the CH[n].CONFIG register. In Single-ended (SE) mode, the negative input will be shorted to ground internally.

In Single-ended mode, the assumption is that the internal ground of the ADC is the same as the external ground that the measured voltage is referred to. The ADC is thus sensitive to ground bounce on the PCB. This can be reduced by configuring SAADC to use differential measurent setting the MODE field of the CH[n].CONFIG register to Diff (differential).