PIC18F4520-I/P - 8-Bit 40MHz 32KB Flash MCU | Microchip | DIP-40
MPN: PIC18F4520-I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.65 | $7.65 |
| 10 | $6.92 | $69.20 |
| 100 | $6.18 | $618.00 |
| 500 | $5.74 | $2,870.00 |
| 1,000 | $5.35 | $5,350.00 |
PIC18F4520-I/P Overview
An 8-bit microcontroller (MCU) is a small computing device built around a CPU with an 8-bit data path, integrated Flash program memory, RAM, and a fixed set of peripherals. The PIC18 family is Microchip's enhanced mid-range line, sitting between the baseline PIC10/12/16 series and the 16-bit dsPIC/PIC24 families. PIC18 MCUs are widely deployed in industrial control, consumer electronics, automotive subsystems, and educational platforms because of their deterministic RISC architecture, low cost, and the mature MPLAB X toolchain.
Key features of the PIC18F4520-I/P include 36 digital I/O pins, four timer modules (one 8-bit and three 16-bit), two capture/compare/PWM (CCP) modules plus one enhanced CCP (ECCP), an internal 31 kHz-8 MHz oscillator with 4x PLL, Fail-Safe Clock Monitor, and a separate Watchdog Timer with its own RC oscillator. The 40-pin PDIP package simplifies prototyping and breadboard-based designs. Operating voltage spans 4.2 V to 5.5 V, and the industrial temperature grade extends from -40C to +85C.
Internally, the device uses a C-compiler-optimized RISC architecture with a hardware 8x8 single-cycle multiplier, a non-multiplexed 16-bit program bus, and a 16-bit instruction word. nanoWatt technology adds multiple idle/sleep modes, ultra-low-power wake-on-interrupt, and a real-time clock using Timer1, enabling battery-friendly designs where average current draw can drop into the microamp range. The Fail-Safe Clock Monitor provides automatic clock-source backup in safety-critical applications.
Typical applications include industrial control panels, sensor interface nodes, motor-control front ends (with ECCP for PWM), USB-to-serial bridges (using a USART plus external converter), home appliance user interfaces, and low-cost data-acquisition front ends that benefit from the 10-bit ADC. Hobbyists and educators also rely on the PIC18F4520 as a teaching vehicle because of its breadboard-friendly DIP form factor and abundant example code.
When designing with this device, ensure the oscillator configuration bits match the chosen clock source and that decoupling capacitors (100 nF plus a bulk 10 uF) are placed within 5 mm of the supply pins. For low-power designs, verify the ADC acquisition time and avoid leaving analog inputs floating; unused digital I/O should be configured as outputs low to minimize transient current.
This page synthesizes distributor pricing as of 2026-09-27, drop-in PIC18 alternatives in the same 40-pin PDIP footprint, and practical design notes not found in the manufacturer datasheet, giving engineers a single decision-ready reference.
Drop-in alternatives for PIC18F4520-I/P — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC18F4520-I/P (same form factor and footprint) — differing in Package, Operating Temperature, Core Architecture, ADC, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4620-I/P
✅ Drop-In✓ In Stock
$5.08 / Unit
View Datasheet →PIC18F4525-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4515-I/P
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18F4420-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4423-I/P
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC18F4520-I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC18 enhanced RISC |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| Data RAM | 1.5 KB (1536 bytes) |
| Data EEPROM | 256 bytes |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| Digital I/O Pins | 36 |
| ADC | 10-bit, up to 13 channels |
| Timers | 1 x 8-bit, 3 x 16-bit |
| CCP / ECCP Modules | 2 CCP + 1 ECCP |
| Communication Peripherals | 1 x USART (EUSART), 1 x MSSP (SPI/I2C) |
| Comparators | 2 |
| Internal Oscillator | 31 kHz to 8 MHz with 4x PLL |
| Watchdog Timer | Yes, with dedicated RC oscillator |
| Operating Temperature | -40C to +85C (Industrial, -I suffix) |
| Package | 40-pin PDIP (P) |
| RoHS Status | Compliant (lead-free matte-tin) |
| Programming / Debug | ICSP via MPLAB ICD/PICkit; MPLAB X IDE |
PIC18F4520-I/P Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear reset (active low) / RE3 digital input only |
| Pin 2 | RA0/AN0 — PORTA bit 0 / ADC channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / ADC channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / ADC channel 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / ADC channel 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / ADC channel 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / Read signal / ADC channel 5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / Write signal / ADC channel 6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / Chip select / ADC channel 7 |
| Pin 11 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKI/RA7 — Crystal oscillator input / external clock input / PORTA bit 7 |
| Pin 14 | OSC2/CLKO/RA6 — Crystal oscillator output / clock output / PORTA bit 6 |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port data |
| Pin 20 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port data |
| Pin 21 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port data |
| Pin 22 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port data |
| Pin 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 25 | RC6/TX/CK — PORTC bit 6 / EUSART TX / EUSART clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / EUSART RX / EUSART data |
| Pin 27 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port data |
| Pin 28 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port data |
| Pin 29 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port data |
| Pin 30 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port data |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 33 | RB0/INT0/FLT0 — PORTB bit 0 / External interrupt 0 / ECCP fault input |
| Pin 34 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 35 | RB2/INT2 — PORTB bit 2 / External interrupt 2 |
| Pin 36 | RB3/CCP2 — PORTB bit 3 / CCP2 alternate pin |
| Pin 37 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 38 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 39 | RB6/PGC — PORTB bit 6 / In-Circuit Debugger clock |
| Pin 40 | RB7/PGD — PORTB bit 7 / In-Circuit Debugger data |
Typical Applications
PIC18F4520-I/P is suitable for 7 applications: Industrial Control Panel MCU, HVAC Sensor Interface Node, Educational Microcontroller Platform, USB-to-Serial Bridge with External FTDI, Low-Cost Data Acquisition Front End, Motor Control with ECCP PWM, Home Appliance User Interface.
Industrial Control Panel MCU
The PIC18F4520-I/P fits industrial control panels because of its 36 digital I/O, 4.2-5.5 V supply that runs directly from 5 V rails, 40 MHz operation for fast control loops, and nanoWatt sleep modes that lower average current in standby. Its 10-bit ADC handles sensor inputs from thermistors, pressure transducers, and 4-20 mA loops. Per Microchip datasheet DS39631E, the Fail-Safe Clock Monitor protects against crystal failure in unattended installations. Pair with an MCP1700 LDO and HC-49 crystal for a turnkey panel controller.
Recommended
HVAC Sensor Interface Node
HVAC sensor nodes benefit from the PIC18F4520-I/P's 13-channel 10-bit ADC (multiplexed temperature, humidity, and CO2 sensors), two comparators for thermostat-style trip points, and the industrial -40C to +85C temperature range. The nanoWatt idle mode keeps power below 100 uA when not sampling, enabling battery-backed sensor taps. ECCP can drive a triac optically-isolated circuit for low-side relay control. According to Microchip datasheet DS39631E, Timer1 in real-time-clock mode sustains accurate 1-second wake-ups on a 32 kHz crystal.
Recommended
Educational Microcontroller Platform
Universities and bootcamps use the PIC18F4520-I/P as a teaching MCU because the 40-pin PDIP drops directly into solderless breadboards without SMD adaptors, the 5 V supply tolerates novice wiring mistakes, and MPLAB X IDE is free. The enhanced 8-bit RISC core introduces students to interrupts, timers, ADC, and UART without 32-bit complexity. Microchip's PICkit 5 (referenced on the product page) programs and debugs the device in-circuit. Sample code libraries and textbook exercises target this exact MPN.
Recommended
USB-to-Serial Bridge with External FTDI
Although the PIC18F4520 lacks native USB, designers pair it with an FT230XS-R USB-UART bridge (also in the XAIPART Site MPN list) using the on-chip EUSART to add a USB service port. The MCU retains control of the application while the FTDI handles USB enumeration and CDC-ACM drivers. This approach gives designers a quick, BOM-cheap method to add configuration ports, firmware upgrade channels, or debug consoles. The PIC18F4520's 32 KB Flash comfortably holds the bootloader + application.
Recommended
Low-Cost Data Acquisition Front End
A 10-bit, 13-channel ADC at 40 MIPS makes the PIC18F4520-I/P suitable for slow-speed multi-channel data loggers that digitize thermocouples, strain gauges, and flow sensors. The MSSP port handles SD card or external FRAM storage, and nanoWatt idle modes drop quiescent current below 100 uA between samples. The 1.5 KB RAM buffers ~700 10-bit samples, with the 256-byte EEPROM storing calibration constants. According to Microchip datasheet DS39631E, the ADC's programmable acquisition time accommodates impedance up to ~10 kOhm.
Recommended
Motor Control with ECCP PWM
The PIC18F4520-I/P's Enhanced Capture/Compare/PWM (ECCP) module generates the PWM signals needed for brushed DC, stepper, or single-phase BLDC motor control up to a few hundred Hz with dead-band control. Three 16-bit timers provide high-resolution timing for velocity loops, and the 10-bit ADC samples current-shunt amplifiers for closed-loop torque control. The 5 V supply tolerates automotive load-dump events when paired with a TVS diode. Microchip application notes AN1079 and AN1300 cover the typical ECCP configuration in this exact device.
Recommended
Home Appliance User Interface
Home appliances such as washing machines, dishwashers, and microwave ovens use the PIC18F4520-I/P as the central HMI MCU. The 36 I/O pins drive 7-segment LEDs, keypads, and buzzer lines directly. The internal oscillator with PLL eliminates the external crystal on cost-sensitive boards. Fail-Safe Clock Monitor provides resilience against EMI from motor drivers. The industrial temperature grade handles under-cabinet thermal loads. Design notes from Microchip recommend external watchdog ICs for safety-critical appliances.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4520-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4620-I/P | PIC18F4525-I/P | PIC18F4515-I/P | PIC18F4420-I/P | PIC18F4423-I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-pin PDIP | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same |
| Flash Memory | 32 KB | 64 KB (+100%) | 48 KB (+50%) | 48 KB (+50%) | 16 KB (-50%) | 16 KB (-50%) |
| Data RAM | 1.5 KB | 3.9 KB (+160%) | 3.9 KB (+160%) | 2 KB (+33%) | 768 B (-49%) | 8 KB (dual channel) |
| EEPROM | 256 B | 1 KB (+300%) | 1 KB (+300%) | 1 KB (+300%) | 256 B (same) | 0 B (internal Flash emulation) |
| Max CPU Speed | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS |
| Supply Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| ADC | 10-bit, 13 ch | 10-bit, 13 ch | 10-bit, 13 ch | 10-bit, 13 ch | 10-bit, 13 ch | 12-bit, 13 ch |
Key Differentiators
- Industry-standard 40-pin PDIP pinout with abundant tooling (vs PIC18F4420-I/P)
- Dual VDD/VSS pin pairs for robust supply distribution (vs PIC18F4515-I/P)
- Mature MPLAB X IDE support with PICkit 5 programmer (vs PIC18F4620-I/P)
Design Notes
Decouple VDD and AVdd (if used) with a 100 nF ceramic capacitor within 5 mm of each pin, plus a 10 uF bulk tantalum or ceramic on the supply trace. The PIC18F4520 has two VDD/VSS pairs (pins 11/12 and 31/32) and both must be connected for the on-chip voltage regulator to function correctly. For nanoWatt designs, configure the secondary oscillator to Timer1 (32 kHz) and use the IDLEN bit to enter sleep from idle; this reduces quiescent current below 1 uA in the deepest sleep mode per datasheet DS39631E section 28.
Two common pitfalls trip up first-time users: (1) leaving analog pins floating injects noise into the ADC; configure ANCON1 bits to make unused analog pins digital, or tie them to Vss via a 10 kOhm resistor. (2) Using the MCLR pin as a normal GPIO requires disabling the MCLR function via the CONFIG3H fuse - on POR the default is MCLR enabled, so the pin will be a reset input. Per Microchip datasheet DS39631E, oscillators without PLL support require careful configuration of OSCCON; otherwise the device boots at an unexpected frequency.
Place the 4 MHz or 10 MHz crystal within 10 mm of pins 13/14 (OSC1/OSC2) with 22 pF ceramic load capacitors grounded at the chip side. Keep the crystal traces short, symmetric, and surrounded by a ground guard ring to avoid coupling noise from nearby switching regulators or RF sources. For board designs where the internal 8 MHz oscillator with 4x PLL is acceptable, you can omit the crystal entirely and free two GPIOs - this is the recommended low-cost option for hobby/educational builds per Microchip application note AN1300.
The PIC18F4520's parallel slave port (PSP) on PORTD shares pins with other peripherals; when operating in PSP mode ensure the data bus traces are short (<50 mm) and that 33 Ohm series resistors are placed near the source to dampen ringing. The EUSART, when driven at higher baud rates (above 115200), requires a low-impedance ground return and 1 nF bypass near the chip. For EMI-sensitive industrial environments, enable the Watchdog Timer Postscale to handle crystal fault recovery without external reset supervision.
Compliance Information
RoHS compliant per Microchip product page. Lead-free matte-tin finish. Halogen-free plastic resin. Conflict-mineral compliant per Microchip supplier disclosures. PIC18F4520-I/P is industrial grade (-40C to +85C); not AEC-Q100 qualified - choose -E (extended, -40C to +125C) variants for automotive-grade thermal profile.
