Pinout Definition Query Tool

Query pinout definitions for electronic components. Essential tool for engineers, hobbyists, and technicians.

Microcontrollers
AVR, PIC, ARM, Arduino
Logic ICs
Gates, Flip-flops, Counters
Memory
EEPROM, Flash, SRAM
Interface
USB, UART, I2C, SPI
Power
Regulators, Converters
Other
Sensors, Drivers, etc.

Pinout Definition: A pinout is a diagram or table that identifies each pin on an electronic component and describes its function, electrical characteristics, and connection requirements.

Enter component name or part number
Select component package type
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Understanding Pinout Definitions

A pinout is a documentation of each pin or connection point on an electronic component, describing its function, electrical characteristics, and connection requirements. Pinouts are essential for designing circuits and troubleshooting electronic systems.

Pinout Components:

  • Pin Number: The physical pin identifier on the component package
  • Pin Name/Function: The functional name or abbreviation (e.g., VCC, GND, CLK)
  • Pin Type: Classification of pin function (Power, Ground, Input, Output, I/O)
  • Electrical Characteristics: Voltage levels, current limits, impedance
  • Alternative Functions: Multipurpose pins with configurable functions

Pin Type Classification

Power (VCC, VDD)
Ground (GND, VSS)
Input
Output
Input/Output (I/O)
Clock/Signal
Pin Type Common Names Function Typical Characteristics
Power VCC, VDD, V+ Supply voltage input Positive voltage, often 3.3V or 5V
Ground GND, VSS, V- Circuit ground reference 0V reference, common return path
Input IN, AIN, EN Signal input to the component High impedance, voltage sensing
Output OUT, DOUT, DRV Signal output from the component Low impedance, current sourcing
I/O IO, Px.x, Dx Bidirectional input/output Configurable direction, often multiplexed
Clock CLK, XTAL, OSC Clock signal input/output Timing reference, often crystal connection

Package Types

1

DIP (Dual In-line Package): Through-hole package with two parallel rows of pins. Common in prototyping and hobbyist projects.

2

SOIC (Small Outline IC): Surface-mount package with gull-wing leads on two sides. Smaller footprint than DIP.

3

QFP/TQFP (Quad Flat Package): Surface-mount package with leads on all four sides. Common in microcontrollers and complex ICs.

4

BGA (Ball Grid Array): Surface-mount package with solder balls underneath. High pin density, used in advanced processors.

Reading Pinout Diagrams

  • Pin 1 Identification: Look for a dot, notch, or beveled edge on the component package
  • Pin Numbering: Typically starts at pin 1 and proceeds counter-clockwise (DIP) or in a specific pattern
  • Power Pins: Usually located at corners or specific positions for better power distribution
  • Signal Grouping: Related pins (like data bus or communication pins) are often grouped together
  • Alternate Functions: Many pins serve multiple purposes depending on configuration

Engineering Note: Always consult the component datasheet for the most accurate and complete pinout information. Pin functions can vary between different package types or revisions of the same component. Verify voltage levels and current limits before connecting to prevent damage.

Frequently Asked Questions

Pin 1 is typically identified by a small dot, notch, or beveled edge on the IC package. On DIP packages, pin 1 is usually at the top-left when the notch is facing left. On QFP packages, there's often a dot in one corner indicating pin 1. Always verify with the component datasheet.

  • VCC: Positive supply voltage for bipolar transistors (originally Collector voltage)
  • VDD: Positive supply voltage for MOS circuits (originally Drain voltage)
  • VSS: Ground or negative supply for MOS circuits (originally Source voltage)
  • VEE: Negative supply voltage for bipolar transistors (originally Emitter voltage)
  • In modern usage, VCC/VDD often mean positive supply and VSS/VEE mean ground/negative supply regardless of technology.

Many modern microcontrollers have pins with alternative functions. A single physical pin might serve as a general-purpose I/O, but can also be configured as a specific communication interface (UART, SPI, I2C), analog input, timer output, or interrupt input. The active function is typically selected via configuration registers in the microcontroller.

Pins often have multiple names because they serve multiple functions. For example, a pin might be labeled "PB5/ADC5/MOSI" indicating it can function as Port B bit 5, Analog-to-Digital Converter input 5, or SPI Master Out Slave In. The active function is determined by the configuration of the device. The primary name is usually listed first, with alternative functions following.

Online pinout databases are generally reliable for common components but should be verified against official datasheets, especially for:
  • New or obscure components
  • Critical applications where errors could cause damage
  • Components with multiple revisions or variants
  • Applications with specific timing or electrical requirements
Always cross-reference with manufacturer documentation when designing production circuits.