USB Connector Symbol
Definition: The USB Connector symbol represents a Universal Serial Bus interface connector used for data communication and power delivery between electronic devices, standardised in USB specifications (USB 2.0, USB 3.x, USB4) and represented with four primary terminals: VBUS (+5 V power), D- (data minus), D+ (data plus), and GND (ground).
Also known as: USB port symbol, USB plug symbol, USB Type-A connector, USB Type-C connector, USB Micro connector, USB interface symbol, Universal Serial Bus connector.
What the USB Connector symbol means
The USB Connector symbol represents a standardised interface that simultaneously carries both power (5 V DC on VBUS, up to 100 W with USB Power Delivery) and data (differential pair D+/D-) between a host device (such as a PC or phone charger) and a peripheral device (such as a flash drive, keyboard, or sensor module). The Universal Serial Bus standard was developed by a consortium led by Intel and published first in 1996, replacing the proliferation of incompatible serial and parallel interface connectors.
In electronic circuit schematics and wiring diagrams, the USB connector symbol marks the interface point between the PCB-mounted USB receptacle or plug and the rest of the circuit. The VBUS pin provides power to bus-powered devices; the D+/D- differential pair carries USB protocol data; and GND provides the return path. Additional pins exist on SuperSpeed (USB 3.x) and USB Type-C connectors for higher data rates and enhanced power negotiation.
How to identify the USB Connector symbol
The USB Connector symbol is drawn as a small rectangle representing the connector housing, with four terminal stubs labelled VBUS (top, +5 V power), D- (left, data minus), D+ (right, data plus), and GND (bottom, ground). In more detailed schematics, Type-C connectors show additional SSRX/SSTX pairs for SuperSpeed data and CC1/CC2 pins for cable orientation and power delivery negotiation. The symbol may also include a shield/ground terminal. The physical connector type (Type-A, Type-B, Micro-B, Mini-B, Type-C) is usually noted in the label or nearby annotation on the schematic.
Function in a circuit
A USB connector provides a standardised, hot-pluggable interface combining power and data. VBUS delivers +5 V at up to 500 mA (USB 2.0), 900 mA (USB 3.x), or up to 5 A at 20 V (USB Power Delivery 3.1, 100 W) to bus-powered devices. The D+/D- differential pair carries bidirectional data at 1.5 Mbps (Low Speed), 12 Mbps (Full Speed), 480 Mbps (Hi-Speed), 5 Gbps (SuperSpeed), or higher. GND is the common reference for both power and data signals. The USB host detects a connected device when D+ or D- is pulled HIGH by a resistor inside the device; the host then enumerates the device and negotiates speed and power requirements.
Standards: IEC vs ANSI
| IEC 60617 | IEC 62680 series (universal serial bus interfaces for data and power): IEC 62680-1 covers common components; IEC 62680-1-2 covers USB 2.0; IEC 62680-1-3 covers USB 3.2. No IEC 60617 schematic symbol is defined; the connector is shown as a labelled rectangle block with pin designations. |
|---|---|
| ANSI/IEEE 315 | USB specifications are published by the USB Implementers Forum (USB-IF), not by ANSI or IEEE. ANSI/UL recognition and FCC Part 15 apply to USB products for safety and EMC. No ANSI Y32.2 / IEEE 315 graphical symbol is defined; the connector is represented as a functional block on schematics. Reference designator: J (for jack/receptacle) or P (for plug). |
| Key difference | IEC 62680 (aligned with USB-IF specifications) and USB-IF USB 2.0/3.x/4 specifications govern the electrical and mechanical interface. Both are internationally harmonised and functionally identical. Schematic representation is a manufacturer-convention block symbol, not a standardised glyph. |
Terminals / pins
| Pin | Name |
|---|---|
| vbus | VBUS |
| gnd | GND |
| dp | D+ |
| dm | D- |
Typical values
USB 2.0: VBUS 5 V ±5%, 500 mA (host), 100 mA (unit load); data 480 Mbps. USB 3.2 Gen 1: 5 Gbps, 900 mA. USB Power Delivery 3.0/3.1: up to 48 V / 5 A = 240 W. D+/D- signal swing: 400 mV differential. USB Type-C: 24 pins including 4× VBUS, 4× GND, 2× CC, 2× SBU, 2× D+/D-, 4× TX/RX SuperSpeed pairs.
Where the USB Connector symbol is used
- Microcontroller development boards (Arduino, STM32, ESP32) for programming and serial communication via USB-to-UART bridge
- Battery charger circuits using VBUS to supply 5 V charging current to lithium-ion cells via a charge controller IC
- USB hub and USB switch ICs in multi-port charging stations and docking stations
- Embedded system firmware update interfaces using USB DFU (Device Firmware Upgrade) mode
- USB CDC (Communications Device Class) virtual COM port interfaces for sensor data logging on PCs
- USB Power Delivery sink/source controllers in laptops, monitors, and USB-C power adapters
Example
On an STM32F103 microcontroller schematic, the USB Connector symbol (Micro-B receptacle, J1) shows VBUS connected through a 1 kΩ ferrite bead and 100 nF bypass capacitor to the MCU's USB VBUS sense pin, D- to PA11 (USB_DM), D+ to PA12 (USB_DP) with a 1.5 kΩ pull-up to 3.3 V for Full Speed detection, and GND to the board power ground — a standard USB device interface circuit that appears on thousands of open-source hardware schematics.
Key facts
- The USB Connector symbol represents a Universal Serial Bus interface with four primary terminals: VBUS (+5 V power), D- (data minus differential), D+ (data plus differential), and GND (ground).
- Governed by IEC 62680 series and USB-IF specifications (USB 2.0, USB 3.2, USB4); reference designator J (receptacle/jack) or P (plug) per IEEE 315.
- USB 2.0 provides 480 Mbps data and up to 500 mA at 5 V; USB 3.2 Gen 2×2 provides 20 Gbps; USB Power Delivery 3.1 delivers up to 240 W (48 V × 5 A).
- Device detection: a 1.5 kΩ pull-up resistor on D+ (Full Speed) or D- (Low Speed) inside the device signals connection to the host.
- USB Type-C has 24 pins — the 4-pin VBUS/GND/D+/D- core is retained, augmented by SuperSpeed TX/RX pairs, CC1/CC2 (power delivery negotiation), and SBU (sideband use) pins.
- Hot-pluggable by design — the USB connector can be inserted and removed while powered without damaging the host or device.
- VBUS (pin 1) always makes contact before D+/D-/GND when inserting a USB plug, following the USB connector contact sequence specification.
- ESD protection diodes on D+ and D- are required on USB data lines to meet USB 2.0 ESD immunity requirements; TVS diodes rated 0.5–1.0 pF typical.
Diagrams that use this symbol
- usb wiring diagram
- usb cable diagram
- usb cable wiring diagram
- usb connection diagram
- usb a pinout diagram
- usb pin diagram
- usb c wiring diagram
- micro usb diagram
Frequently asked questions
What does the USB connector symbol look like?
The USB connector symbol is a small rectangle representing the connector housing with four labelled terminal stubs: VBUS (top, +5 V), D- (data minus), D+ (data plus), and GND (ground). The label beside the rectangle identifies the physical connector type — Type-A, Micro-B, Type-C, etc. Detailed Type-C connector symbols show additional pin stubs for CC1, CC2, and SuperSpeed differential pairs.
What does the USB connector symbol mean in a circuit?
The USB connector symbol marks the point where a USB cable or device interfaces with the PCB. It shows that power (+5 V VBUS) and USB data (D+, D- differential pair) enter or leave the circuit at that connector. Designers route VBUS to a power rail or battery charger and connect D+/D- to the USB transceiver of a microcontroller or dedicated USB controller IC.
What are the pins of a USB connector?
Standard USB 2.0 Type-A or Micro-B connectors have four pins: pin 1 VBUS (+5 V), pin 2 D- (data minus), pin 3 D+ (data plus), and pin 4 GND. USB 3.x connectors add five more pins: SSTX+, SSTX-, SSRX+, SSRX- (SuperSpeed differential pairs) and GND_DRAIN. USB Type-C has 24 pins total including CC1, CC2, and four VBUS/GND pins.
What voltage does USB provide?
Standard USB provides 5 V DC on the VBUS pin. USB 2.0 allows up to 500 mA (2.5 W); USB 3.x allows up to 900 mA (4.5 W); USB Battery Charging 1.2 allows up to 1.5 A (7.5 W); USB Power Delivery 3.0 allows up to 20 V at 5 A (100 W); USB Power Delivery 3.1 allows up to 48 V at 5 A (240 W).
What is the designator letter for a USB connector on a schematic?
The reference designator is J (jack or receptacle) for a USB female connector or P (plug) for a USB male connector, per ANSI Y32.2 / IEEE 315 conventions. A schematic might label a USB Micro-B receptacle as J2 or a USB Type-C receptacle as J1 — the designator number following the letter is unique to that connector on the board.
What standard defines the USB connector?
USB connectors and their electrical interface are defined by USB-IF (USB Implementers Forum) specifications — USB 2.0, USB 3.2, USB4 — which are harmonised with IEC 62680 series (IEC 62680-1-2 for USB 2.0, IEC 62680-1-3 for USB 3.2). Physical connector dimensions are standardised in IEC 62680-1-1. No IEC 60617 or ANSI Y32.2 graphical symbol standard applies.
What is the difference between USB Type-A, Micro-B, and Type-C connector symbols?
All three share the same four core pins (VBUS, D+, D-, GND) and use the same basic rectangular block symbol on schematics. The difference is in their physical form and additional pins: Type-A is the flat rectangular host-side connector; Micro-B adds USB 3.x SuperSpeed pins (ID pin for OTG detection); Type-C adds CC1/CC2 pins for cable orientation detection and USB Power Delivery negotiation, shown as extra terminal stubs in detailed Type-C symbols.
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