Pinout USB
Complete Guide to USB 2.0, 3.0, and 3.1 (USB-C) Connectors
"Comprehensive pinout diagrams and technical descriptions for all major USB connector types, including Standard-A, B, Mini, Micro, and USB-C."
This web-based reference provides a detailed breakdown of USB connector pin configurations, signal functions, voltage levels, and color coding across generations: USB 2.0, USB 3.0, and USB 3.1 (Type-C). All information follows official specifications from the USB Implementers Forum (USB-IF).
Ideal for engineers, technicians, hobbyists, and students working with embedded systems, DIY electronics, or device repair.
What Is USB?
Universal Serial Bus (USB) is a standardized interface for connecting peripherals to computers and mobile devices. It supports:
- Data transfer
- Power delivery (up to 240W in USB PD)
- Device charging
- Hot-swapping
Each USB version introduces new features:
- USB 2.0: Up to 480 Mbps
- USB 3.0: Up to 5 Gbps
- USB 3.1 Gen 2: Up to 10 Gbps
- USB 3.2 / USB4: Up to 40 Gbps
The physical connectors vary by type and generation, but all follow strict pin assignments.
USB Connector Types Overview
| Connector | Pins | Use Case |
|---|---|---|
| USB 2.0 A/B | 4 pins | Hosts, printers, keyboards |
| Mini/Micro USB 2.0 | 5 pins | Older phones, cameras |
| USB 3.0 A/B | 9/11 pins | High-speed data, external drives |
| Micro USB 3.0 | 10 pins | Smartphones, tablets |
| USB 3.1 C (USB-C) | 24 pins | Reversible, high-power, fast data |
Note: USB-C supports reversibility, dual-role operation, and Power Delivery (PD).
USB 2.0 – Standard A & B Connectors
Standard A: Standard B:
┌─────────┐ ┌─────────┐
│ 4 3 2 1 │ │ 1 2 │
└─────────┘ └─────────┘
↑ ↑
Plug View Plug View
Pin Configuration (4-Pin)
| Pin | Signal | Color Code | Function |
|---|---|---|---|
| 1 | VCC (+5V) | Red | Power supply (up to 500mA) |
| 2 | Data - (D-) | White | Differential data pair (-) |
| 3 | Data + (D+) | Green | Differential data pair (+) |
| 4 | Ground | Black | Signal and power return |
Full-duplex communication using differential signaling
No ESD protection on host side? Use TVS diodes!
Mini/Micro USB 2.0 – Standard A & B
Standard A: Standard B: ┌───────┐ ┌───────┐ │ 1 2 3 4 5 │ │ 1 2 3 4 5 │ └───────┘ └───────┘
Pin Configuration (5-Pin)
| Pin | Signal | Function |
|---|---|---|
| 1 | VCC (+5V) | Power supply |
| 2 | Data - (D-) | USB 2.0 data negative |
| 3 | Data + (D+) | USB 2.0 data positive |
| 4 | None | Host detection: connected to ground in hosts, open in devices |
| 5 | Ground | Common ground |
Pin 4 enables automatic detection of host vs. slave
Used in older smartphones, GPS units, and digital cameras
USB 3.0 – Standard A & B Connectors
USB 3.0 A (9-Pin)
Plug View: ┌─────────────┐ │ 5 6 7 8 9 │ │ 4 3 2 1 │ └─────────────┘
| Pin | Signal | Function |
|---|---|---|
| 1 | VCC (+5V) | Power supply |
| 2 | D- | USB 2.0 data negative |
| 3 | D+ | USB 2.0 data positive |
| 4 | GND | Power ground |
| 5 | RX2- | USB 3.0 receive line (-) |
| 6 | RX2+ | USB 3.0 receive line (+) |
| 7 | GND | Signal ground |
| 8 | TX2- | USB 3.0 transmit line (-) |
| 9 | TX2+ | USB 3.0 transmit line (+) |
Backward compatible with USB 2.0
Speed: Up to 5 Gbps (SuperSpeed)
USB 3.0 B (11-Pin)
Plug View: ┌─────────────┐ │ 9 8 7 6 5 │ │ 10 11 │ │ 4 3 │ └─────────────┘
| Pin | Signal | Function |
|---|---|---|
| 1 | VCC (+5V) | Power supply |
| 2 | D- | USB 2.0 data negative |
| 3 | D+ | USB 2.0 data positive |
| 4 | GND | Power ground |
| 5 | TX2- | USB 3.0 transmit line (-) |
| 6 | TX2+ | USB 3.0 transmit line (+) |
| 7 | GND | Signal ground |
| 8 | RX2- | USB 3.0 receive line (-) |
| 9 | RX2+ | USB 3.0 receive line (+) |
| 10 | DPWR | Power provided by device (e.g., bus-powered hub) |
| 11 | GND | Return for DPWR |
Rarely used; replaced by USB-C in modern devices
Micro USB 3.0 (10-Pin)
Plug View: ┌─────────────────────┐ │ 1 0 9 8 7 6 │ │ 5 4 3 2 1 │ └─────────────────────┘
| Pin | Signal | Function |
|---|---|---|
| 1 | VCC (+5V) | Power supply |
| 2 | D- | USB 2.0 data negative |
| 3 | D+ | USB 2.0 data positive |
| 4 | ID | OTG identification (host/device role) |
| 5 | GND | Power ground |
| 6 | TX2- | USB 3.0 transmit line (-) |
| 7 | TX2+ | USB 3.0 transmit line (+) |
| 8 | GND | Signal ground |
| 9 | RX2- | USB 3.0 receive line (-) |
| 10 | RX2+ | USB 3.0 receive line (+) |
Used in early smartphones and tablets before USB-C adoption
Supports On-The-Go (OTG) mode
USB 3.1 Type-C (24-Pin) – Reversible Connector
Plug View (Top Side): ┌────────────────────────────┐ │ 1 2 3 4 5 6 7 8 9 10 11 12 │ └────────────────────────────┘ │ 13 14 15 16 17 18 19 20 21 22 23 24 │ └────────────────────────────┘
Pin Configuration (24-Pin)
| Pin | Signal | Function |
|---|---|---|
| 1 | GND (A1) | Ground |
| 2 | TX1+ (A2) | SuperSpeed transmit (+) |
| 3 | TX1- (A3) | SuperSpeed transmit (-) |
| 4 | Vbus (A4) | +5V power supply |
| 5 | CC1 (A5) | Configuration Channel (detects orientation, power roles) |
| 6 | D+ (A6) | USB 2.0 data positive |
| 7 | D- (A7) | USB 2.0 data negative |
| 8 | SBU1 (A8) | Sideband use (for video/audio, alternate modes) |
| 9 | Vbus (A9) | +5V power supply (second path) |
| 10 | RX2- (A10) | SuperSpeed receive (-) |
| 11 | RX2+ (A11) | SuperSpeed receive (+) |
| 12 | GND (A12) | Ground |
| 13 | GND (B12) | Ground (symmetric side) |
| 14 | RX1+ (B11) | SuperSpeed receive (+) |
| 15 | RX1- (B10) | SuperSpeed receive (-) |
| 16 | Vbus (B9) | +5V power supply |
| 17 | SBU2 (B8) | Sideband use |
| 18 | D- (B7) | USB 2.0 data negative |
| 19 | D+ (B6) | USB 2.0 data positive |
| 20 | CC2 (B5) | Configuration Channel (backup) |
| 21 | Vbus (B4) | +5V power supply |
| 22 | TX2- (B3) | SuperSpeed transmit (-) |
| 23 | TX2+ (B2) | SuperSpeed transmit (+) |
| 24 | GND (B1) | Ground |
Fully reversible plug
Dual-role data flow (host/device)
Supports USB Power Delivery (up to 240W)
Supports DisplayPort and HDMI via Alternate Mode
Design Tips for Engineers
- Always route D+/D- as differential pairs with controlled impedance (~90Ω)
- Keep Vbus trace short and wide for better current handling
- Use TVS diodes on D+/D- lines for ESD protection
- Add pull-up resistors on CC pins for proper negotiation
- Follow USB-IF compliance guidelines for certification
Standards Compliance
- USB 2.0: USB-IF Specification 2.0
- USB 3.0: USB 3.0 Specification (Rev. 1.0)
- USB 3.1: USB 3.1 Specification (Rev. 1.0)
- USB-C: USB Type-C Specification (Rev. 2.1)
All modern devices must comply with these standards for interoperability.
