PGA280: Layout

Hi Christopher, 

Welcome to e2e

Power Supply Decoupling:

• Place bypass capacitors in very close proximity to the PGA280 supply pins
• For bipolar supplies (±2.5V): use a local bypass cap on VSON, with an optional 10Ω series resistor for R/C filtering (PGA280: Power supply decoupling - Amplifiers forum - Amplifiers - TI E2E support forums)
• For unipolar supply (+5V/GND): VSON connects directly to the ground plane (no cap needed)
• Use low-noise, stable, linear supplies

Digital Interface Routing:

• Include a proper ground plane directly beneath digital traces to prevent reflections and overshoots
• Use 50Ω or 10Ω series resistors on SPI digital input pins
• Keep noise sources away from sensitive analog signal chain circuits

General Best Practices:

• Avoid SPI communication during precise measurements to prevent coupled noise
• Avoid large current loads on GPIO and SDO pins
• Noise coupling impact is layout-dependent—separation of analog and digital domains is critical (PGA280 Communication via SPI)

I would reference the sibling device, PGA281EVM, for more detailed layout guidance: PGA281EVM User's Guide

All the best,
Carolina