When rebooting a Raspberry Pi 4, the 3.3V rail is reset which causes problems for some HATs and projects.

The 3v3 Sustain solves this problem! The board fits in between a Raspberry Pi and a HAT/pHAT and provides a stable 3.3V (300mA max) during reboots.

It also has a cutout to help keep the Pi 4 cooler (can be used with the Pimoroni Fan Shim or similar).

Example use

One of the features added to the Cluster HAT v2.x was to allow the controller Pi to reboot without powering off the Pi Zeros. With the Raspberry Pi 4, this no longer works as once the 3.3V rail is reset, the I/O expander loses power and powers off the Pi Zeros.

Contents

• Pre-soldered 3v3 Sustain PCB
• 4x 12mm M2.5 spacers
• 8x 6mm M2.5 screws

Note: Raspberry Pi 4, ClusterHAT and Fan Shim not included