Raspberry Pi 4 Model B Full _top_ Schematic
Overview
Ethernet
: True Gigabit Ethernet is implemented via the Broadcom BCM54213PE PHY, which connects directly to the SoC’s RGMII interface. The 40-Pin GPIO Header
- Integration: Unlike desktop RAM sticks, the Pi 4 uses "Package-on-Package" (PoP) or close-proximity mounting (depending on the specific board revision and RAM density).
- Address Lines: The schematic shows the dense address and data bus lines connecting the memory chip to the BCM2711. The layout of these lines is critical for signal integrity at high clock speeds.
Final Thoughts
- Reset: A POR and reset button circuit tied to the SoC reset pin, including supervisor ICs that monitor rail voltages.
- Wake/power-state control: Power key logic via the PMIC allows soft-shutdown and wake functions.
LPDDR4 SDRAM
: Unlike previous models, the Pi 4 supports up to 8GB of RAM. The memory is interfaced directly with the BCM2711 via a dedicated high-speed bus. VideoCore VI GPU Raspberry Pi 4 Model B Full Schematic
- 40-pin header: Standard pinout with 3.3V I/O, dedicated power pins, I2C, SPI, UART, PCM/I2S, PWM lines. Each IO shows series resistors, ESD diodes and option for level shifting.
- HAT EEPROM: 24C02/24C512 EEPROM on I2C with board ID and configuration. Schematic shows pull-ups and address pins.
- Protection: Transient diodes and polyfuses for 5V pins where appropriate.
Standard:
The 40-pin GPIO header remains a staple. The schematic confirms it is backward compatible with older HATs. However, it adds new "muxing" options for UART, SPI, and I2C, giving developers more flexibility for complex sensor arrays. Key GPIO Features: 27 GPIO pins. Power: 3.3V and 5V power pins available. Ground: Multiple ground points for signal integrity. Overview Ethernet : True Gigabit Ethernet is implemented