Eliminating Ground Loops in Mixed-Signal Systems

Overview

Improving measurement integrity by resolving noise issues in a mixed analogue and digital system.

Technologies

Analogue electronics | PCB design | Mixed-signal systems | Embedded hardware

Define the Problem

A mixed analogue and digital system was exhibiting excessive noise on sensor measurements, resulting in unstable readings and reduced system accuracy.

Diagnose the Root Cause

Investigation identified interference caused by digital return currents coupling into sensitive analogue reference paths through an unsuitable grounding architecture.

Key engineering challenges included:

• Mixed analogue and digital circuitry

• Multiple current return paths

• Sensitive low-level measurements

• Limited redesign scope

Deliver the Solution

We redesigned the grounding architecture to better isolate analogue and digital domains while optimising current return paths across the PCB.

Key Outcomes

• Clean and stable sensor measurements

• Reduced analogue noise levels

• Improved measurement accuracy

• Increased overall system stability