PIC18F4420T-I/ML - 8-bit PIC MCU 16KB Flash 44-QFN | Microchip
MPN: PIC18F4420T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.95 | $4.95 |
| 10 | $4.45 | $44.50 |
| 100 | $3.85 | $385.00 |
| 500 | $3.4 | $1,700.00 |
| 1,000 | $2.95 | $2,950.00 |
| 3,300 | $2.65 | $8,745.00 |
PIC18F4420T-I/ML Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, optimized for deterministic, low-cost embedded control. PIC18 series parts extend the classic PIC architecture with a 16-bit instruction word, hardware multiplier and nanoWatt power management, sitting between simple PIC10/12/16 MCUs and 16-bit dsPIC/dsPIC33/PIC24 devices. PIC18F4420 specifically belongs to the 28/40/44-pin enhanced flash family that targets human-machine interface, sensor signal conditioning and small protocol bridging tasks.
Key features of this part include the nanoWatt power-managed core with multiple idle/sleep modes, a 10-bit ADC with up to 13 input channels, two 8-bit and three 16-bit timers, two capture/compare/PWM modules, an enhanced USART, an MSSP module that supports SPI and I2C (master/slave), and a parallel slave port. The on-chip ICD2/ICD3 debug interface and self-programmable flash make firmware iteration fast in development.
Architecturally, the device uses a Harvard-cache RISC engine, 32-level hardware stack and interrupt-driven peripherals, with the ADC sharing a dedicated voltage reference. The exposed thermal pad of the QFN-44 package keeps junction-to-ambient thermal resistance low, allowing reliable operation across the industrial -40C to +85C range.
Typical applications include industrial control panels, sensor signal conditioning nodes, USB-to-UART bridges, small graphic LCD drivers, motor control (PWM-driven DC and stepper stages at low power), and HVAC/home appliance user interfaces. It is also widely used as a teaching platform for PIC assembly and C development.
When designing with this MCU, place decoupling capacitors (0.1 uF plus 10 uF bulk) within a few millimetres of VDD/VSS pairs, and solder the QFN EP pad to a continuous ground plane for thermal and electrical reasons. Use the MSSP for I2C/SPI peripherals instead of bit-banging, and reserve the parallel slave port pins if bus-mode external memory is anticipated, since they cannot be used as GPIO when the PSP is enabled.
This page combines manufacturer datasheet specifications, distributor pricing, drop-in 44-pin QFN alternatives and practical design notes that are not collated in a single place on Microchip's product page.
Drop-in alternatives for PIC18F4420T-I/ML — 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 PIC18F4420T-I/ML (same form factor and footprint) — differing in Package, Core Architecture, Timers, ADC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4520T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4410T-I/ML
✅ Drop-In✓ In Stock
$2.4 / Unit
View Datasheet →PIC18F46K20-I/ML
✅ Drop-In✓ In Stock
$3.52 / Unit
View Datasheet →PIC18F45K20T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4510T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F44K20T-I/ML
✅ Drop-In✓ In Stock
$2.84 / Unit
View Datasheet →PIC18F4420T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 8-bit RISC |
| Program Memory (Flash) | 16 KB |
| Data RAM | 768 bytes |
| Data EEPROM | 256 bytes |
| Maximum CPU Speed | 40 MHz (10 MIPS at 40 MHz, 16 MIPS at 64 MHz via PLL where supported) |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| Digital I/O Pins | 36 |
| ADC | 10-bit, up to 13 channels |
| Timers | 2 x 8-bit, 3 x 16-bit |
| Capture/Compare/PWM | 2 x ECCP |
| Communication | EUSART, MSSP (SPI / I2C) |
| Parallel Slave Port | Yes |
| Operating Temperature | -40C to +85C (Industrial, suffix -I) |
| Package | 44-pin QFN (ML) with exposed pad |
| Mounting Type | Surface Mount, Tape & Reel (suffix -T) |
| RoHS Status | Compliant |
PIC18F4420T-I/ML Pin Configuration
| Pin 1 | OSC1/CLKI/RA7 — Oscillator input / external clock / GPIO RA7 |
| Pin 2 | OSC2/CLKO/RA6 — Oscillator output / clock out / GPIO RA6 |
| Pin 3 | MCLR/VPP/RE3 — Master clear (reset) input / programming voltage / GPIO RE3 |
| Pin 4 | RA0/AN0 — GPIO RA0 / ADC analog input 0 |
| Pin 5 | RA1/AN1 — GPIO RA1 / ADC analog input 1 |
| Pin 6 | RA2/AN2/VREF- — GPIO RA2 / ADC analog input 2 / ADC negative reference |
| Pin 7 | RA3/AN3/VREF+ — GPIO RA3 / ADC analog input 3 / ADC positive reference |
| Pin 8 | RA4/T0CKI/C1OUT — GPIO RA4 / Timer0 clock input / comparator 1 output |
| Pin 9 | RA5/AN4/SS/HLVDIN/C2OUT — GPIO RA5 / ADC AN4 / SPI slave select / HLVD input / comparator 2 output |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 12 | RB0/INT0/FLT0 — GPIO RB0 / external interrupt 0 / ECCP fault input |
| Pin 13 | RB1/INT1 — GPIO RB1 / external interrupt 1 |
| Pin 14 | RB2/INT2 — GPIO RB2 / external interrupt 2 |
| Pin 15 | RB3/INT3/CCP2A — GPIO RB3 / external interrupt 3 / CCP2 output |
| Pin 16 | RB4/KBI0 — GPIO RB4 / interrupt-on-change KBI0 |
| Pin 17 | RB5/KBI1 — GPIO RB5 / interrupt-on-change KBI1 |
| Pin 18 | RB6/KBI2/PGC — GPIO RB6 / KBI2 / ICD clock (PGC) |
| Pin 19 | RB7/KBI3/PGD — GPIO RB7 / KBI3 / ICD data (PGD) |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply |
| Pin 22 | RC0/T1OSO/T1CKI — GPIO RC0 / Timer1 oscillator output / Timer1 clock input |
| Pin 23 | RC1/T1OSI/CCP2B — GPIO RC1 / Timer1 oscillator input / CCP2 output B |
| Pin 24 | RC2/CCP1/P1A — GPIO RC2 / CCP1 output / PWM output A |
| Pin 25 | RC3/SCK/SCL — GPIO RC3 / SPI clock / I2C clock |
| Pin 26 | RC4/SDI/SDA — GPIO RC4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — GPIO RC5 / SPI data out |
| Pin 28 | RC6/TX/CK — GPIO RC6 / EUSART TX / EUSART clock |
| Pin 29 | RC7/RX/DT — GPIO RC7 / EUSART RX / EUSART data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply |
| Pin 32 | RD0/PSP0 — GPIO RD0 / parallel slave port bit 0 |
| Pin 33 | RD1/PSP1 — GPIO RD1 / parallel slave port bit 1 |
| Pin 34 | RD2/PSP2 — GPIO RD2 / parallel slave port bit 2 |
| Pin 35 | RD3/PSP3 — GPIO RD3 / parallel slave port bit 3 |
| Pin 36 | RD4/PSP4 — GPIO RD4 / parallel slave port bit 4 |
| Pin 37 | RD5/PSP5/P1B — GPIO RD5 / PSP5 / PWM output B |
| Pin 38 | RD6/PSP6/P1C — GPIO RD6 / PSP6 / PWM output C |
| Pin 39 | RD7/PSP7/P1D — GPIO RD7 / PSP7 / PWM output D |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — Positive supply |
| Pin 42 | RE0/RD/AN5 — GPIO RE0 / parallel port read / ADC AN5 |
| Pin 43 | RE1/WR/AN6 — GPIO RE1 / parallel port write / ADC AN6 |
| Pin 44 | RE2/CS/AN7 — GPIO RE2 / parallel port chip select / ADC AN7 |
| Pin EP | EP — Exposed thermal pad - connect to ground for thermal dissipation |
Typical Applications
PIC18F4420T-I/ML is suitable for 7 applications: Industrial Control Panels, Sensor Signal Conditioning Nodes, USB-to-UART / SPI Bridge, Small Graphic LCD Driver, Low-Power Motor Control (DC/Stepper), HVAC / Home Appliance User Interface, Educational / Development Platform.
Industrial Control Panels
The PIC18F4420T-I/ML is well suited for industrial HMI and control panels because its 36 GPIO plus 10-bit ADC handle button scans, rotary encoder inputs and 4-20 mA sensor conditioning without external glue logic. The 16 MIPS core is sufficient for menu rendering on character LCDs and basic modbus ASCII polling. Its industrial -40C to +85C temperature grade and the QFN exposed pad that ties to a ground plane keep the part thermally stable in sealed control cabinets. Place 0.1 uF ceramic caps within 5 mm of VDD/VSS pairs to keep ADC readings clean.
Recommended
Sensor Signal Conditioning Nodes
For sensor signal conditioning nodes the PIC18F4420T-I/ML offers a 10-bit 13-channel ADC, 16 MIPS throughput and a hardware MSSP that supports both SPI and I2C sensor interfaces. The 4.2-5.5 V supply rail matches typical industrial 5 V transducer levels directly, eliminating level shifters. Its nanoWatt sleep currents below 1 uA in deep sleep enable battery-backed wireless sensor nodes that wake periodically to sample and transmit. Use the on-chip timer1 with external 32.768 kHz crystal for accurate RTC-style wake intervals.
Recommended
USB-to-UART / SPI Bridge
When used as a USB-to-UART or USB-to-SPI bridge host-side controller, the PIC18F4420T-I/ML leverages its EUSART and MSSP modules to translate between a USB device controller and legacy RS-232 or SPI peripherals. Its 16 MIPS core handles USB enumeration handshakes and protocol multiplexing with room to spare for protocol glue logic. The QFN-44 exposed pad keeps the package thermally cool at full UART baud rates and continuous USB traffic. Designers should keep the USB D+/D- traces matched to 90 ohm differential and isolated from switching nodes.
Recommended
Small Graphic LCD Driver
The PIC18F4420T-I/ML drives small graphic LCDs (128x64 monochrome or smaller) using its MSSP SPI channel for high-speed pixel streaming and a single GPIO line for the chip-select/reset control. The 16 MIPS throughput sustains comfortable frame rates even with software font rendering, and the parallel slave port can be re-tasked for 8-bit parallel LCDs if required. Industrial temperature grade plus surface-mount QFN makes it appropriate for sealed appliance user interfaces that must operate in -20C environments.
Recommended
Low-Power Motor Control (DC/Stepper)
For DC brushed or low-power stepper motor control, the PIC18F4420T-I/ML's two ECCP modules deliver complementary PWM with programmable dead-band and hardware fault shutdown, eliminating software timing jitter at high PWM frequencies. Its 16 MIPS throughput runs closed-loop PID at kilohertz rates, and its 5 V-tolerant I/O directly drives small MOSFET gate drivers through 4.7 kohm pull-ups. The exposed pad of the QFN-44 must be soldered to a continuous copper pour to dissipate the small but steady quiescent dissipation of the MCU itself.
Recommended
HVAC / Home Appliance User Interface
White-goods and HVAC user-interface boards benefit from the PIC18F4420T-I/ML because its 36 GPIO scan large key matrices directly, the 10-bit ADC reads NTC temperature sensors without external components, and the QFN-44 small footprint keeps board cost low in high-volume consumer appliances. Industrial temperature grade covers under-cabinet appliance environments, while nanoWatt sleep modes reduce standby power to satisfy energy regulations. Pair it with a character LCD and a small buzzer driven from a CCP PWM channel for complete UI functionality.
Recommended
Educational / Development Platform
The PIC18F4420T-I/ML is widely used in university embedded courses and maker training because the PIC18 instruction set balances simplicity with a 16-bit instruction word that exposes students to real RISC concepts. Its in-circuit debugger support (ICD2/ICD3) and free MPLAB X IDE lower the entry barrier, and the QFN-44 exposes the parallel slave port and full peripheral set for advanced lab exercises. PIC training boards frequently use this part, and code written for the PIC18F4420 typically migrates cleanly to PIC18F4520 or K-series upgrades in later coursework.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4420T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4520T-I/ML | PIC18F4410T-I/ML | PIC18F46K20-I/ML | PIC18F45K20T-I/ML | PIC18F4510T-I/ML |
|---|---|---|---|---|---|---|
| Package | 44-pin QFN (ML) with EP | 44-pin QFN (ML) - same | 44-pin QFN (ML) - same | 44-pin QFN (ML) - same | 44-pin QFN (ML) - same | 44-pin QFN (ML) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 16 KB | 32 KB | 16 KB | 64 KB | 32 KB | 32 KB |
| Data RAM | 768 B | 1536 B | 768 B | 3896 B | 1536 B | 1536 B |
| Maximum CPU Speed | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 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 | 1.8 V to 5.5 V (XLP) | 1.8 V to 5.5 V (XLP) | 4.2 V to 5.5 V |
| Digital I/O | 36 | 36 | 36 | 36 | 36 | 36 |
| ADC | 10-bit, 13 channels | 10-bit, 13 channels | 10-bit, 13 channels | 10-bit, 14 channels | 10-bit, 14 channels | 10-bit, 13 channels |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Balanced memory + peripherals in compact 44-QFN (vs PIC18F4520T-I/ML)
- Wider supply voltage and nanoWatt XLP in same package (vs PIC18F46K20-I/ML)
- Faster 16-MIPS core in same package (vs PIC18F45K20T-I/ML)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of each VDD/VSS pin pair, and add a single 10 uF bulk tantalum or ceramic capacitor close to the supply entry point. The exposed thermal pad of the QFN-44 must be soldered to a continuous, unbroken ground copper pour - this is essential for thermal dissipation and is electrically tied to VSS internally. Avoid routing high-speed signals (SPI clock, oscillator traces) directly under the exposed pad, since the pad is connected to ground and would add capacitive loading.
Keep the OSC1/OSC2 crystal traces short and symmetric, with the load capacitors placed within 2-3 mm of the oscillator pins and a ground guard ring surrounding the crystal network to suppress noise coupling. The PGC/PGD ICD lines (RB6/RB7) should be dedicated and not used as outputs during debug - place test pads on these nets so that the ICD probe can be attached without disturbing the running firmware. When using the parallel slave port, reserve RD0-RD7 and RE0-RE2 as a bus group, and route them as parallel traces with matched lengths to avoid skew.
Do not exceed 5.5 V on any VDD pin - the PIC18F4420 is a 5 V part and the absolute-maximum VDD of 7 V will permanently damage the MCU. The MCLR reset pin must have a 10 kohm pull-up to VDD and a 100 nF capacitor to ground for in-circuit debugging; omitting the cap prevents the ICD probe from establishing a handshake. When migrating from PIC18F2420/2520 (28/40-pin) to PIC18F4420/4520 (40/44-pin), check the parallel slave port pin assignments because some PSP pins replace general-purpose GPIO on the larger pin-count variants.
Compliance Information
RoHS and lead-free compliant per Microchip product page. Industrial -40C to +85C temperature grade (suffix -I); not AEC-Q100 qualified for automotive - consider PIC18FxxK20 automotive variants if needed.
