This application note provides PCB design guidelines for SPEAr1340, including power integrity, PCB layer stacking, vias, power and DDR interface.
This document serves as a guide for experienced printed circuit board designers working with the SPEAr1340 embedded microprocessor. It focuses on achieving reliable high-speed memory interfaces by addressing power integrity and minimizing parasitic inductances.
Key topics include recommended PCB layer stacking configurations, via padstack dimensions, and specific guidelines for ground and power supply connections to ensure low impedance paths. The note also details requirements for DDR memory interface routing, including decoupling capacitor layouts, signal trace length matching, and USB routing constraints.
The document recommends a minimum of 6 layers for the PCB stack.
Trace length inside the ball field must be less than 1 mm.
Trace length outside the ball field must be less than 0.25 mm.