The Original Microchip PIC16F73 8-Bit Flash Microcontroller is a classic, robust, and versatile 28-pin MCU manufactured by Microchip Technology. Encapsulated in an industry-standard 0.300-inch skinny DIP-28 (PDIP-28 / SPDIP-28) through-hole package, it is powered by an efficient mid-range 8-bit PIC RISC core operating at speeds up to 20 MHz. The PIC16F73 integrates a comprehensive set of hardware peripherals, including a 5-channel 8-bit Analog-to-Digital Converter (ADC), two Capture/Compare/PWM (CCP) modules, three hardware timers, a full-duplex Addressable USART, and a Master Synchronous Serial Port (MSSP) supporting SPI and I2C modes. Renowned for its high noise immunity, wide supply voltage operating window, and 25mA high-current sink/source I/O pins, the PIC16F73 is widely utilized in industrial motor controllers, UPS and pure sine wave inverters, smart battery chargers, power management systems, automotive subsystems, and embedded development projects.

Specifications

• Part Number / Model: PIC16F73-I/SP / PIC16F73 (Industrial Temperature Grade, Skinny DIP)
• Manufacturer: Microchip Technology
• Core Architecture: Mid-Range 8-Bit PIC RISC Core (35 Single-Word Instructions)
• Package Type: DIP-28 
• Operating Voltage Range (VDD): 2.0V to 5.5V DC (Full 20 MHz speed rated from 4.0V to 5.5V DC)
• Maximum CPU Clock Speed: Up to 20 MHz (200 ns instruction execution cycle time at 20 MHz)
• Clock Sources: External Quartz Crystal, Ceramic Resonator, or RC Oscillator via OSC1/OSC2 pins
• Program Memory (Flash): 7.0 KB (4,096 Words Flash Program Memory, 1,000 erase/write cycles)
• Data SRAM: 192 Bytes
• General Purpose I/O (GPIO): 22 User I/O Pins across Port A, Port B, and Port C (with 25mA sink/source per pin)
• Analog-to-Digital Converter (ADC): 8-Bit Successive Approximation ADC with 5 Multiplexed Input Channels (AN0 to AN4)
• Capture / Compare / PWM (CCP) Modules: 2 Independent CCP Modules (10-Bit PWM Resolution, up to 20 kHz+ switching)
• Hardware Timers:
  • Timer0: 8-Bit Timer/Counter with 8-bit software-programmable prescaler
  • Timer1: 16-Bit Timer/Counter with external crystal/clock oscillator capability
  • Timer2: 8-Bit Timer with 8-bit Period Register (PR2), prescaler, and postscaler
• Serial Communication Peripherals:
  • 1x Addressable USART (Hardware Full-Duplex UART with 9-bit address detection support)
  • 1x MSSP (Master Synchronous Serial Port supporting 3-wire SPI Master/Slave and I2C Slave/Master modes)
• Hardware Interrupt Sources: 11 Independent Interrupt Sources (External INT pin, TMR overflows, CCP, USART, ADC, etc.)
• Power-On Features: Power-on Reset (POR), Power-up Timer (PWRT), Oscillator Start-up Timer (OST), and Watchdog Timer (WDT)
• Operating Ambient Temperature (TA): -40°C to +85°C (Industrial Grade)
• Storage Temperature Range (Tstg): -65°C to +150°C
• Pinout Configuration (SPDIP-28):
  • Pin 1: MCLR / VPP (Active-Low Master Clear Reset / High-Voltage Programming Voltage)
  • Pin 2: RA0 / AN0 (Port A0 / ADC Channel 0)
  • Pin 3: RA1 / AN1 (Port A1 / ADC Channel 1)
  • Pin 4: RA2 / AN2 (Port A2 / ADC Channel 2)
  • Pin 5: RA3 / AN3 / VREF (Port A3 / ADC Channel 3 / External Voltage Reference Input)
  • Pin 6: RA4 / T0CKI (Port A4 / Timer0 External Clock Input - Open-Drain Output)
  • Pin 7: RA5 / AN4 / SS (Port A5 / ADC Channel 4 / SPI Slave Select)
  • Pin 8: VSS (Digital Ground / 0V Reference)
  • Pin 9: OSC1 / CLKIN (Main Oscillator Crystal Input / External Clock)
  • Pin 10: OSC2 / CLKOUT (Main Oscillator Crystal Output / Clock Output)
  • Pin 11: RC0 / T1OSO / T1CKI (Port C0 / Timer1 Oscillator Output / Timer1 Clock Input)
  • Pin 12: RC1 / T1OSI / CCP2 (Port C1 / Timer1 Oscillator Input / CCP2 Capture, Compare, PWM)
  • Pin 13: RC2 / CCP1 (Port C2 / CCP1 Capture, Compare, PWM)
  • Pin 14: RC3 / SCK / SCL (Port C3 / SPI Clock / I2C Clock)
  • Pin 15: RC4 / SDI / SDA (Port C4 / SPI Data In / I2C Data)
  • Pin 16: RC5 / SDO (Port C5 / SPI Data Out)
  • Pin 17: RC6 / TX / CK (Port C6 / USART Asynchronous Transmit / Synchronous Clock)
  • Pin 18: RC7 / RX / DT (Port C7 / USART Asynchronous Receive / Synchronous Data)
  • Pin 19: VSS (Digital Ground / 0V Reference - Internally Connected)
  • Pin 20: VDD (Positive Power Supply Input, +2.0V to +5.5V)
  • Pin 21: RB0 / INT (Port B0 / External Hardware Interrupt Input)
  • Pin 22: RB1 (Port B1 General Purpose I/O)
  • Pin 23: RB2 (Port B2 General Purpose I/O)
  • Pin 24: RB3 / PGM (Port B3 / Low-Voltage In-Circuit Serial Programming Enable)
  • Pin 25: RB4 (Port B4 General Purpose I/O / Interrupt-on-Change)
  • Pin 26: RB5 (Port B5 General Purpose I/O / Interrupt-on-Change)
  • Pin 27: RB6 / PGC (Port B6 / In-Circuit Serial Programming Clock / Interrupt-on-Change)
  • Pin 28: RB7 / PGD (Port B7 / In-Circuit Serial Programming Data / Interrupt-on-Change)

Features

• Dual 10-Bit Hardware CCP Modules: Built-in CCP1 and CCP2 modules allow precise PWM generation, hardware frequency measurement, and pulse timing without placing software timing burdens on the CPU.
• High-Drive 25mA I/O Ports: Every standard I/O pin can source and sink up to 25mA directly, allowing direct control of indicator LEDs, optocouplers, small relays, and logic gates.
• Hardware Serial USART & MSSP: Hardware UART (TX/RX) alongside simultaneous hardware SPI / I2C serial communications enables multi-device networking, RS-485 Modbus telemetry, and peripheral interfacing.
• High Noise Immunity: Engineered for harsh industrial environments, featuring high ESD resistance, Brown-out Reset (BOR), and a built-in Watchdog Timer (WDT) with an independent on-chip RC oscillator.
• Prototyping-Friendly 0.300-Inch SPDIP-28 Package: Slim DIP footprint fits standard breadboards, narrow 28-pin DIP sockets, and single/double-sided through-hole PCBs.

Common Applications

• Power Inverters & UPS Systems: PWM generation, voltage regulation, battery charging algorithms, and fault monitoring in modified and pure sine wave inverters.
• Industrial Motor Controllers & Drivers: Variable speed driving, soft-start regulation, and tachometer feedback for DC motors, fans, and pumps.
• Smart Battery Chargers: Multi-stage CC/CV battery management for Lead-Acid, NiCd/NiMH, and Lithium-based systems.
• Security & Access Control Systems: Keypad scanning, relay switching, serial RS-485 communication, and LCD front-panel management.
• DIY Robotics & Embedded Projects: Core controller for robotics rovers, sensor sampling arrays, and custom embedded systems.

Usage Tips

• In-Circuit Serial Programming (ICSP): For flashing and debugging with Microchip PICkit (PICkit 3, 4, 5) or standard ICSP programmers, connect:
  • VPP/MCLR to Pin 1
  • VDD (+5.0V) to Pin 20
  • VSS (GND) to Pin 8 and Pin 19
  • PGD / ICSPDAT to Pin 28 (RB7)
  • PGC / ICSPCLK to Pin 27 (RB6)
  • (If using High-Voltage ICSP, pull Pin 24 / RB3 / PGM low through a 10kΩ resistor or disable LVP in configuration words).
• Power Supply Decoupling: Place a **0.1µF (100nF) ceramic capacitor** as close as possible across Pin 20 (VDD) and Pin 19 (VSS), and connect Pin 8 (VSS) directly to your common ground plane to minimize switching noise during high-speed ADC sampling.
• MCLR Reset Circuit: Connect Pin 1 (MCLR) to VDD through a **10kΩ pull-up resistor** in series with a 100Ω damping resistor. For noisy environments, add a 100nF filter capacitor to ground at the junction (ensure ICSP programming lines are isolated during programming).
• Oscillator Crystal Loading: When using an external quartz crystal (e.g., 4 MHz, 8 MHz, 16 MHz, or 20 MHz) between Pin 9 (OSC1) and Pin 10 (OSC2), connect two **15pF to 22pF ceramic capacitors** from each crystal pin to ground, and select the appropriate oscillator mode (XT or HS) in the device configuration fuses.
• Port A Digital / Analog Configuration (ADCON1): By default at startup, Port A pins (RA0–RA5) power up as analog inputs. To use them as general-purpose digital I/O, you must explicitly configure the **ADCON1 register** (e.g., set `ADCON1 = 0x06` or `0x07` depending on the desired analog/digital split).
• Port A4 Open-Drain Output: Note that Pin 6 (RA4/T0CKI) is an **open-drain output**. When configured as a digital output, it requires an external pull-up resistor (e.g., 4.7kΩ to 10kΩ) connected to VDD to pull the pin HIGH.

Datasheet