Pi 5 - 5V Power Flow

Disclaimer

This page was produced through reverse engineering by a completely untrained hobbyist with a multimeter and more curiosity than qualifications. It is not based on official schematics, manufacturer documentation, or any formal electronics education. Treat everything here as "best guess" — it may be wrong, incomplete, or misleading.

This diagram shows how 5V power travels through the board from the USB-C input. The DA9091 PMIC controls a DMG7430LFG N-channel MOSFET as a hot-swap switch, ramping the gate over ~400µs to limit inrush current into the >350µF of capacitance on the 5V rail.

Component references (e.g. "Top #8") refer to the numbered component lists on the Pi 5 Components page — "Top" or "Bottom" indicates which side of the board, and the number matches the ID in that table.

Power Flow

flowchart LR
    USB(["⚡ USB-C (Top #8, J1)"]) -- "5V In → Drain" --> MOSFET["N-Ch MOSFET\nDMG7430LFG\n(Bottom #3)"]
    USB -- "Drain sense" --> PMIC_DRAIN["DA9091 Pin 21\nHOTSWAP_DRAIN"]
    PMIC_GATE["DA9091 Pin 22\nHOTSWAP_GATE"] -- "Gate drive\n(~400µs ramp)" --> MOSFET
    MOSFET -- "Source → 5V Rail" --> RAIL["5V Rail"]
    RAIL --> PMIC_5V["DA9091 Pins 7 & 9\n(+5V Input)"]
    RAIL --> BOARD["Rest of Board"]
    RAIL -. "Probe here" .-> TP63["📍 TP63 (5V)"]

    PMIC_DRAIN --- PMIC["DA9091 PMIC\n(Top #12)"]
    PMIC_GATE --- PMIC
    PMIC_5V --- PMIC

MOSFET Pinout — Bottom #3 (DMG7430LFG-7)

5V Out ➡	Pin 1 (Source)		Pin 8 (Drain)	⬅ USB-C (5V In)
	Pin 2 (Source)		Pin 7 (Drain)
	Pin 3 (Source)		Pin 6 (Drain)
⬅ DA9091 Pin 22 (HOTSWAP_GATE) — 9.72V	Pin 4 (Gate)		Pin 5 (Drain)

5V Test Points

See the full Test Points (Rev 1.1) page for voltage readings.

Sources

The PMIC pin assignments (HOTSWAP_GATE, HOTSWAP_DRAIN, +5V inputs) were verified from the CM5 Reverse Engineering project by Tube Time. The Compute Module 5 uses the identical DA9091 PMIC and DMG7430LFG hot-swap MOSFET circuit.