Powers the VideoCore VI GPU and foundational silicon logic. 3. High-Speed I/O and Peripheral Buses
The schematic connects the SoC’s internal MAC to an external Broadcom BCM54213PE Gigabit Ethernet PHY via an RGMII (Reduced Gigabit Media Independent Interface).
The represents a significant leap forward in the world of single‑board computing. Since its release, this compact yet powerful computer has powered everything from DIY media centres and retro gaming consoles to industrial automation systems and edge‑AI projects. For engineers, hardware developers, and enthusiastic tinkerers, understanding the board at a schematic level is the first step toward creating custom hardware, designing add‑on boards, or troubleshooting complex issues.
If you are designing an add-on board (HAT), the reduced schematic + GPIO documentation is sufficient. If you are trying to repair a Pi 4, the reduced schematic plus multimeter probing usually works. Raspberry Pi 4 Model B Full Schematic
Because the official link is well known, many educational and maker websites mirror the same PDF for convenience:
At the heart of the schematic lies the application processor. The schematic details:
Early revisions of the Raspberry Pi 4 schematic revealed a famous design quirk: both Configuration Channel (CC1 and CC2) pins on the USB-C port shared a single 5.1kΩ pull-down resistor. This caused smart chargers (like E-marked MacBook cables) to detect the Pi as an audio accessory and withhold power. Revision 1.2 of the schematic corrected this by giving each CC pin its own independent 5.1kΩ resistor, ensuring universal USB-PD compatibility. 3. LPDDR4 Memory Architecture Powers the VideoCore VI GPU and foundational silicon logic
A crucial part of the schematic is the MXL7704 power management IC, which regulates the input voltage to the various rails needed by the SoC, RAM, and USB ports. Key Schematic Sections 1. Power Management and Input
– Not realistic for hobbyists; meant for large-volume commercial integrators.
Even in its reduced form, the Pi 4B schematic is an invaluable tool for several tasks. The represents a significant leap forward in the
Early revisions (Rev 1.1) of the Pi 4 schematic lacked individual pull-down resistors on the two Configuration Channel (CC1 and CC2) lines, sharing a single 5.1kΩ resistor instead. This caused e-marked smart chargers to detect the Pi as an audio accessory and deny power. Revised schematics show individual 5.1kΩ resistors on CC1 and CC2, resolving compatibility with all USB-C chargers. PMIC Rails
The schematic confirms that the 5V pins on the 40-pin header bypass the USB-C input TVS diode and reverse-current protection. Back-powering the board through these pins requires an external stabilized, regulated power source to prevent permanent silicon damage.