The Raspberry Pi 3 Model A+ is a compact and efficient single-board computer designed for space-constrained and low-power projects. It uses the same 40-pin GPIO header layout found on larger Raspberry Pi boards, ensuring strong compatibility with sensors, HATs, and expansion modules. Below is the complete GPIO pinout and hardware overview for building reliable Raspberry Pi 3A+ based projects.
Pi 3A+ GPIO Pinout
| Pin | Name / Function | Pin | Name / Function |
|---|---|---|---|
| 1 | 3.3V Power | 2 | 5V Power |
| 3 | GPIO2 (SDA1) | 4 | 5V Power |
| 5 | GPIO3 (SCL1) | 6 | Ground |
| 7 | GPIO4 | 8 | GPIO14 (TXD0) |
| 9 | Ground | 10 | GPIO15 (RXD0) |
| 11 | GPIO17 | 12 | GPIO18 (PCM_CLK / PWM0) |
| 13 | GPIO27 | 14 | Ground |
| 15 | GPIO22 | 16 | GPIO23 |
| 17 | 3.3V Power | 18 | GPIO24 |
| 19 | GPIO10 (MOSI) | 20 | Ground |
| 21 | GPIO9 (MISO) | 22 | GPIO25 |
| 23 | GPIO11 (SCLK) | 24 | GPIO8 (CE0) |
| 25 | Ground | 26 | GPIO7 (CE1) |
| 27 | ID_SD (I²C EEPROM) | 28 | ID_SC (I²C EEPROM) |
| 29 | GPIO5 | 30 | Ground |
| 31 | GPIO6 | 32 | GPIO12 (PWM0) |
| 33 | GPIO13 (PWM1) | 34 | Ground |
| 35 | GPIO19 (PCM_FS / SPI1 MISO) | 36 | GPIO16 |
| 37 | GPIO26 | 38 | GPIO20 (PCM_DIN / SPI1 MOSI) |
| 39 | Ground | 40 | GPIO21 (PCM_DOUT / SPI1 SCLK) |
Raspberry Pi 3A+ Specifications
The 3A+ features a “stripped-back” design to save power and space, removing the Ethernet jack and three of the four USB ports found on the Model B.
| Feature | Specification | Key Detail |
|---|---|---|
| Processor | Broadcom BCM2837B0 | 64-bit Quad-core ARM Cortex-A53 @ 1.4 GHz |
| GPU | Broadcom VideoCore IV | Supports OpenGL ES 1.1, 2.0; 1080p30 H.264 video |
| RAM | 512MB LPDDR2 SDRAM | Shared with GPU; optimized for lighter OS tasks |
| USB Ports | 1× USB 2.0 port | Direct SoC connection; no internal hub (compact design) |
| Networking | Wireless only | No onboard Ethernet (RJ45) |
| Wireless | Dual-band 802.11ac | Supports both 2.4 GHz and 5 GHz bands |
| Bluetooth | Bluetooth 4.2 / BLE | Improved data speeds and power efficiency |
| Video Output | Full-size HDMI | Supports 1080p; includes DSI display connector |
| Audio / Video | 3.5mm TRRS jack | Combined stereo audio and composite video |
| Power Input | Micro-USB (5V / 2.5A) | Primary input; GPIO pins 2 & 4 supported |
| Storage | MicroSD slot | Push-pull slot for OS boot and storage |
| Dimensions | 65 × 56 mm | Same footprint as original Pi 1 Model A+ |
Compatibility
- 3.3V Logic Level
- No built-in ADC
- Supports I²C, SPI, UART, PWM, and PCM
- Supports 1080p video output
- No Ethernet Port
Helpful Resources
- Getting started with Raspberry pi 3A+
- Download the datasheet: Official PDF
- Benchmark and review: article