PIC18F4420-E/P - 8-bit MCU, 16KB Flash, 40MHz, 40-PDIP | Microchip
MPN: PIC18F4420-E/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.96 | $3.96 |
| 10 | $3.62 | $36.20 |
| 100 | $3.21 | $321.00 |
| 500 | $2.85 | $1,425.00 |
| 1,000 | $2.55 | $2,550.00 |
PIC18F4420-E/P Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (Flash/ROM), data memory (RAM), peripherals and I/O on one silicon die, executing instructions in 8-bit-wide data paths. RISC microcontrollers like the PIC18 family prioritise a small, fixed instruction set and Harvard memory architecture so that most instructions complete in a single cycle, simplifying deterministic firmware timing for real-time control tasks. The PIC18F4420-E/P sits within the broader taxonomy: microcontroller -> 8-bit MCU -> PIC18 family -> nanoWatt enhanced-Flash sub-family.
Key features that distinguish this part include the nanoWatt Technology power-saving modes (run, idle, sleep, and deep-sleep with RTCC), the 10-bit A/D converter with a built-in acquisition timer, two analog comparators, two CCP/ECCP modules, an enhanced USART, an MSSP port supporting SPI and I²C, and self-programming Flash with an internal programmable LDO of 3.3 V or 5 V.
The architecture combines a 16-bit wide instruction word with 8-bit data paths, providing 10 MIPS sustained throughput at 40 MHz. Peripherals are accessed through an SFR-based memory map that keeps ISR latency short and interrupt handling deterministic for real-time control loops.
Typical applications include industrial sensor interfacing, motor control front-ends (stepper/small DC), HVAC controllers, automotive body and accessory modules, appliance control boards, and general-purpose embedded platforms that need a through-hole DIP form factor for rapid prototyping or legacy-system drop-in.
When designing with the PIC18F4420-E/P, ensure the ICSP programming clock and data pins (RB6/RB7 on 40-pin parts) are reserved for the debugger/programmer header and not loaded by external circuitry; also add a decoupling capacitor within 5 mm of each VDD/VSS pair as recommended in the manufacturer datasheet.
This page synthesizes distributor pricing, drop-in equivalents, and practical design notes not found in the standalone Microchip datasheet, supporting faster sourcing and BOM decisions.
Drop-in alternatives for PIC18F4420-E/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 PIC18F4420-E/P (same form factor and footprint) — differing in Mounting Type, Package, Timers, Operating Temperature, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4420-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4520-I/P
✅ Drop-In✓ In Stock
$5.35 / Unit
View Datasheet →PIC18F4620-I/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$5.08 / Unit
View Datasheet →PIC18F4420T-I/PT
✅ Drop-In✓ In Stock
$2.8098 / Unit
View Datasheet →PIC16F1777-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4420-E/P Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| Maximum Clock Speed | 40 MHz |
| Program Memory (Flash) | 16 KB (8K x 16) |
| RAM | 768 bytes |
| Data EEPROM | 256 bytes |
| Supply Voltage (Vdd) | 4.2 V to 5.5 V |
| I/O Pins | 36 |
| A/D Converter | 10-bit, up to 13 channels |
| PWM Modules (CCP/ECCP) | 1 CCP + 1 ECCP |
| Comparators | 2 |
| Communication Interfaces | EUSART, MSSP (SPI/I2C) |
| Timers | Timer0, Timer1, Timer2, Timer3 |
| Operating Temperature | -40 C to +125 C (Extended) |
| Package | 40-pin PDIP (DIP-40, 0.600 inch) |
| Mounting Type | Through Hole |
| Program Memory Type | Flash |
| Instruction Set | PIC18 (16-bit instructions, 8-bit data path, Harvard) |
| MIPS (peak) | 10 MIPS at 40 MHz |
| Low-Power Modes | nanoWatt: Run, Idle, Sleep, Deep-Sleep with RTCC |
| Temperature Grade | E (Extended Industrial, -40C to +125C) |
| RoHS Status | Compliant (per Microchip product page) |
PIC18F4420-E/P Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear (reset) input or digital input RE3 |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / A/D negative reference |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / A/D positive reference |
| Pin 6 | RA4/T0CKI/C1OUT — PORTA bit 4 / Timer0 clock / comparator 1 output |
| Pin 7 | RA5/AN4/SS/HLVDIN/C2OUT — PORTA bit 5 / analog 4 / SPI SS / HLVD input / comparator 2 output |
| Pin 8 | OSC1/CLKI/RA7 — Oscillator input / external clock / PORTA bit 7 |
| Pin 9 | OSC2/CLKO/RA6 — Oscillator output / clock out / PORTA bit 6 |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator in / CCP2 I/O |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / CCP1 I/O |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / EUSART transmit / clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / EUSART receive / data |
| Pin 18 | VSS1 — Ground reference for logic and I/O |
| Pin 19 | VDD1 — Positive supply for logic and I/O |
| Pin 20 | RB0/INT0/FLT0 — PORTB bit 0 / external interrupt 0 / ECCP fault input |
| Pin 21 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 22 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 23 | RB3/INT3/ECCP2/P2A — PORTB bit 3 / external interrupt 3 / ECCP2 output / PWM 2A |
| Pin 24 | RB4/KBI0 — PORTB bit 4 / interrupt-on-change |
| Pin 25 | RB5/KBI1/PGM — PORTB bit 5 / KBI / LVP programming |
| Pin 26 | RB6/KBI2/PGC — PORTB bit 6 / KBI / ICSP clock |
| Pin 27 | RB7/KBI3/PGD — PORTB bit 7 / KBI / ICSP data |
| Pin 28 | RD0 — PORTD bit 0 |
| Pin 29 | RD1 — PORTD bit 1 |
| Pin 30 | RD2 — PORTD bit 2 |
| Pin 31 | RD3 — PORTD bit 3 |
| Pin 32 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 33 | RD5/PSP5/P1A — PORTD bit 5 / PSP / PWM 1A |
| Pin 34 | RD6/PSP6/P1B — PORTD bit 6 / PSP / PWM 1B |
| Pin 35 | RD7/PSP7/P1C — PORTD bit 7 / PSP / PWM 1C |
| Pin 36 | VSS2 — Ground reference for ADC core |
| Pin 37 | VDD2 — Positive supply for ADC core |
| Pin 38 | RE0/RD/AN5 — PORTE bit 0 / read strobe / analog 5 |
| Pin 39 | RE1/WR/AN6 — PORTE bit 1 / write strobe / analog 6 |
| Pin 40 | RE2/CS/AN7 — PORTE bit 2 / chip-select strobe / analog 7 |
Typical Applications
PIC18F4420-E/P is suitable for 6 applications: Industrial Sensor Interface & Data Acquisition, HVAC & Building Automation Controllers, Small Appliance Control Boards, Automotive Body & Accessory Modules, Educational & Legacy Hardware Prototyping, Peripheral Board Bridging & GLUE Logic.
Industrial Sensor Interface & Data Acquisition
The PIC18F4420-E/P's 13-channel, 10-bit A/D converter and 4.2 V to 5.5 V operation make it a natural fit for industrial sensor-interface boards that aggregate multiple analog signals. Its 16 KB Flash comfortably hosts a multi-channel scanning loop, while 256 bytes of EEPROM store calibration constants retrieved at start-up. The nanoWatt deep-sleep mode drops current to microampere levels between scans, extending life on battery-backed remote telemetry units. Pair with RS-485 transceivers and the EUSART for long-cable industrial communication, and use ECCP to drive optocouplers for 4-20 mA loops.
Recommended
HVAC & Building Automation Controllers
HVAC controllers rely on multiple analog inputs (temperature, pressure, humidity) and digital I/O (relay drivers, triac gates). PIC18F4420-E/P's 36 I/O pins handle keypad scanning, LCD drive, and triac firing with headroom for spare channels. The extended -40 C to +125 C temperature grade ensures reliable operation in unconditioned plant rooms. The ECCP module is well suited to variable-fan PWM control, and the 10-bit ADC reading thermistor bridges can achieve better than 0.1 C resolution with averaging. Flash in-circuit reprogramming enables field firmware updates over ICSP without board removal.
Recommended
Small Appliance Control Boards
Coffee machines, washing-machine sub-boards and small kitchen appliances benefit from the PIC18F4420-E/P's mix of analog sensors and PWM outputs in a Through-Hole PDIP-40 footprint, which is friendly to wave-soldered mass production. The 40 MHz core executes PID loops and button-debounce state machines without strain, while the EUSART provides service/debug port capability. Designers using mains-volt zero-cross detection use the CCP/ECCP capture feature for line-frequency timing. EEPROM stores user profiles and last-cycle settings that survive power removal.
Recommended
Automotive Body & Accessory Modules
Although not AEC-Q100 qualified, the PIC18F4420-E/P's extended -40 C to +125 C temperature grade and robust internal peripherals are commonly used by retrofit, aftermarket and non-safety automotive modules such as lighting controllers, alarm interfaces and seat-control sub-modules. The 10-bit ADC reads thermistors and current-sense shunts, the ECCP drives indicator LEDs and small solenoids, and the MSSP port talks to I2C temperature or pressure sensors. Pair with a TVS array on supply and signal lines for module-level protection in 12 V vehicle systems.
Recommended
Educational & Legacy Hardware Prototyping
Through-Hole 40-pin PDIP remains the preferred package in university embedded-systems laboratories and rapid-prototyping shops because it fits breadboards directly without SMD breakout. The PIC18F4420-E/P offers a generous feature set that exposes students to ADC, PWM, UART and I2C peripherals on a single part, supported by MPLAB X IDE and a free XC8 compiler. Its 16 KB Flash holds representative real-world embedded curricula, while ICSP via RB6/RB7 lets students iterate between code edits and running firmware without chip removal.
Recommended
Peripheral Board Bridging & GLUE Logic
In legacy industrial racks where 5 V logic still rules, the PIC18F4420-E/P offers 36 tolerant I/O pins capable of bridging older serial protocols (RS-232, RS-485, I2C, SPI) to modern displays or microcontrollers acting as a serial-to-parallel 'glue' controller. Its 16 KB Flash holds small custom protocol stacks, and 768 bytes of RAM handle command buffering between interfaces. The MSSP port supports both SPI master/slave and I2C master/slave, enabling bridging between dissimilar peripherals without external logic.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4420-E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4420-I/P | PIC18F4520-I/P | PIC18F4620-I/P | PIC16F1777-I/P |
|---|---|---|---|---|---|
| Brand | 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 |
| Core | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC16 8-bit RISC |
| Program Flash | 16 KB | 16 KB (same) | 32 KB (+100%) | 64 KB (+300%) | 14 KB (-12%) |
| RAM | 768 B | 768 B (same) | 1.5 KB (+95%) | 3.9 KB (+419%) | 1 KB (+30%) |
| Maximum Clock | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 32 MHz (-20%) |
| 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 | 2.3 V to 5.5 V |
| Temperature Grade | Extended -40C to +125C | Industrial -40C to +85C | Industrial -40C to +85C (E grade option available) | Industrial -40C to +85C (E grade option available) | Industrial -40C to +85C (E grade option available) |
Key Differentiators
- Extended -40C to +125C temperature grade on a 40-pin PDIP footprint (vs PIC18F4420-I/P)
- 16 KB Flash + 13-channel 10-bit ADC in a single Through-Hole 40-PDIP chip (vs PIC16F1777-I/P)
- nanoWatt Technology with Deep-Sleep RTCC (vs PIC18F4520-I/P)
Design Notes
Place a 0.1 uF decoupling capacitor within 5 mm of every VDD/VSS pin pair (pin pairs 19/18 and 37/36) per the Microchip layout recommendation. Add a bulk 10 uF tantalum or aluminium-polymer cap at the board supply entry. The PIC18F4420-E/P nanoWatt deep-sleep mode draws only a few microamperes with RTCC active, making CR2032-backup designs feasible.
Reserve RB6 and RB7 for ICSP clock and data and avoid loading these pins with more than 1.5 mA during programming. If the application must drive heavy loads on RB6/RB7, add an in-line series resistor of at least 470 ohm to limit programming-port voltage drop. For the 40-pin PDIP variant, place a 100 kohm pull-up on MCLR/RE3 (pin 1) so the device runs on power-up.
PIC18F4420-E/P is not the 'LF' variant - it requires 4.2 V minimum. Designers copying an existing PIC18LF4420 layout into a new 5 V rail must remove any low-voltage-only code paths and confirm brown-out is set for the higher range. Also, distinguish the 40-pin PDIP ('/P') from 44-pin TQFP ('/PT') and 28-pin variants ('/SO'/'/ML'/'/SP') - the same .hex file may map pins differently between packages.
At full 40 MHz core clock on 5 V supply, the PIC18F4420-E/P draws up to ~25 mA active. Estimated: total dissipation is roughly 125 mW worst-case, well within the 40-pin PDIP's 1 W thermal budget without a heatsink. In sealed enclosures above 70 C ambient, however, derate by 30 percent and consider a 4-layer PCB for spreader copper.
For EUSART at 115,200 baud over long cables, route TX/RX lines next to a ground plane and add a 100 ohm series resistor at each driver to limit ringing. For MSSP I2C at 400 kHz, place 4.7 kohm pull-ups on SCL/SDA only if the slaves do not supply their own, and keep total trace length below 100 mm to remain within the I2C rise-time budget on 5 V rails.
Compliance Information
RoHS and lead-free compliance per Microchip product page. The -E temperature grade is industrial-grade and is not AEC-Q100 qualified. For automotive safety applications, contact Microchip about the PIC18F-K42 AEC-Q100 family or use a separately-qualified MCU.
