PIC18F4431-I/P - 8-bit MCU, 16KB Flash, 40MHz, 40-PDIP | Microchip
MPN: PIC18F4431-I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.1 | $7.10 |
| 10 | $6.45 | $64.50 |
| 100 | $5.62 | $562.00 |
| 500 | $5.05 | $2,525.00 |
| 1,000 | $4.5 | $4,500.00 |
PIC18F4431-I/P Overview
A PIC18F microcontroller is an 8-bit Harvard-architecture MCU built around an enhanced RISC core with a modified instruction set that retains code compatibility with the earlier PIC16 family while adding linear memory, 16-bit instructions, and a hardware multiplier. It sits in the broader taxonomy: microcontroller -> embedded processor -> semiconductor. PIC18F parts are typically used in applications that need more compute, RAM, and peripherals than PIC16F MCUs but do not justify a 16-bit dsPIC33 or 32-bit ARM Cortex-M0 device.
Key features include a 40 MHz internal/external oscillator block, two 8-bit timers plus three 16-bit timers, two capture/compare/PWM modules, an enhanced USART, an MSSP (SPI/I2C) port, a 10-bit A/D with up to 9 channels, and a parallel slave port. The integrated Power Control PWM module provides up to six PWM channels with hardware fault inputs, which is unusual for a general-purpose 8-bit MCU and makes the PIC18F4431 especially suited to motor and motion control loops. On-chip debug and In-Circuit Serial Programming (ICSP) are supported through two dedicated pins.
The device operates across an industrial temperature range of -40C to +85C (denoted by the 'I' suffix) and uses the standard 40-pin PDIP pinout shared with several other PIC18F44xx parts. Compliance includes RoHS status per Microchip's product page and standard PIC18F nanoWatt low-power operating modes such as Sleep, Idle, and oscillator switching.
Typical applications include BLDC and PMSM motor control (the Power Control PWM and 9-channel 10-bit ADC are tuned for closed-loop FOC), HVAC fan and pump control, and industrial sensor conditioning. The 5V-tolerant digital I/O simplify interfacing to legacy 5 V analog front-ends and opto-isolated gate drivers.
When designing with this device, pay attention to the ICP/ICSP pin allocation: PGD/PGC must remain accessible for in-circuit programming and debugging. Decouple VDD/VSS pairs locally and follow Microchip's PIC18F4531/4431 errata guidance for the Power Control PWM module startup sequence.
This page synthesizes verified distributor pricing, parametric alternatives from the same PIC18F family, and design notes not consolidated on any single distributor page.
Drop-in alternatives for PIC18F4431-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 PIC18F4431-I/P (same form factor and footprint) — differing in Package, Operating Temperature, Timers, Communication, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4531-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4439-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F46K22-I/P
✅ Drop-In✓ In Stock
$2.61 / Unit
View Datasheet →PIC18F452-I/P
✅ Drop-In✓ In Stock
$5.1 / Unit
View Datasheet →PIC18F442-I/P
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC18F4410-I/P
✅ Drop-In✓ In Stock
$4.7 / Unit
View Datasheet →PIC18F4320-I/P
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC18F4431-I/P Maximum Ratings & Electrical Characteristics
| Core | PIC18F 8-bit RISC |
| Program Memory | 16 KB (8K x 16) Flash |
| RAM | 768 bytes |
| EEPROM | 256 bytes |
| Maximum CPU Speed | 40 MHz |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| I/O Pins | 34 (36 per digchip datasheet; 34 functional per Microchip datasheet) |
| A/D Converter | 10-bit, up to 9 channels |
| PWM Channels | Up to 6 (Power Control PWM module) |
| Timers | 2 x 8-bit, 3 x 16-bit |
| Communication | 1 x EUSART, 1 x MSSP (SPI/I2C) |
| Package | 40-pin PDIP (DIP-40) |
| Operating Temperature | -40C to +85C (Industrial) |
| Mounting Type | Through-Hole |
| Power-Saving Modes | nanoWatt (Sleep, Idle, Run modes) |
| ICSP/ICD | Yes (PGD/PGC pins) |
| RoHS | Compliant (per Microchip product page) |
| Lifecycle Status | Active |
PIC18F4431-I/P Pin Configuration
| Pin 1 | /MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — PORTA bit 0 / analog AN0 |
| Pin 3 | RA1 — PORTA bit 1 / analog AN1 |
| Pin 4 | RA2 — PORTA bit 2 / analog AN2 / VREF- |
| Pin 5 | RA3 — PORTA bit 3 / analog AN3 / VREF+ |
| Pin 6 | RA4 — PORTA bit 4 / analog AN4 |
| Pin 7 | RA5 — PORTA bit 5 / analog AN5 / digital I/O |
| Pin 8 | RE0 — PORTE bit 0 / digital I/O |
| Pin 9 | RE1 — PORTE bit 1 / digital I/O |
| Pin 10 | RE2 — PORTE bit 2 / digital I/O |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1 — Crystal/clock input |
| Pin 14 | OSC2 — Crystal/clock output |
| Pin 15 | RC0 — PORTC bit 0 |
| Pin 16 | RC1 — PORTC bit 1 |
| Pin 17 | RC2 — PORTC bit 2 |
| Pin 18 | RC3 — PORTC bit 3 |
| Pin 19 | RD0 — PORTD bit 0 |
| Pin 20 | RD1 — PORTD bit 1 |
| Pin 21 | RD2 — PORTD bit 2 |
| Pin 22 | RD3 — PORTD bit 3 |
| Pin 23 | RC4 — PORTC bit 4 / USB D- |
| Pin 24 | RC5 — PORTC bit 5 / USB D+ |
| Pin 25 | RC6 — PORTC bit 6 / TX |
| Pin 26 | RC7 — PORTC bit 7 / RX |
| Pin 27 | RD4 — PORTD bit 4 |
| Pin 28 | RD5 — PORTD bit 5 / P1B |
| Pin 29 | RD6 — PORTD bit 6 / P1C |
| Pin 30 | RD7 — PORTD bit 7 / P1D |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage |
| Pin 33 | RB0 — PORTB bit 0 / INT0 |
| Pin 34 | RB1 — PORTB bit 1 / INT1 |
| Pin 35 | RB2 — PORTB bit 2 / INT2 |
| Pin 36 | RB3 — PORTB bit 3 / PGM |
| Pin 37 | RB4 — PORTB bit 4 |
| Pin 38 | RB5 — PORTB bit 5 / PGD |
| Pin 39 | RB6 — PORTB bit 6 / PGC |
| Pin 40 | RB7 — PORTB bit 7 |
Typical Applications
PIC18F4431-I/P is suitable for 6 applications: BLDC Motor Control, Industrial Sensor Conditioning & PWM Drive, HVAC Fan and Pump Control, Uninterruptible Power Supply (UPS) Control, Automotive Body Control Modules, Smart Sensor Hubs.
BLDC Motor Control
The PIC18F4431-I/P's 6-channel Power Control PWM with hardware fault inputs and complementary outputs is purpose-built for three-phase BLDC/PMSM commutation. With a 40 MHz oscillator delivering 10 MIPS, the firmware can execute a sensorless or Hall-sensor FOC loop with sufficient bandwidth for the PWM reload period. The 9-channel 10-bit A/D samples phase currents via op-amp sense chains, and the 4.2-5.5 V supply directly powers 5 V gate drivers like the IR2104. Compared to using PIC18F452 + external PWM logic, this part eliminates an entire analog comparator dead-band circuit.
Recommended
Industrial Sensor Conditioning & PWM Drive
For industrial sensor signal conditioning, the PIC18F4431-I/P pairs its 10-bit A/D (9 channels, 5 V tolerant) with up to 6 PWM channels for excitation or proportional control outputs. Industrial 4-20 mA loops and 0-10 V analog outputs can be generated from the PWM filtered through op-amp buffers, simplifying BOM by combining MCU and DAC functions. The industrial -40C to +85C rating and nanoWatt power management suit always-on PLC input modules.
Recommended
HVAC Fan and Pump Control
HVAC variable-speed fan and pump controllers benefit from the PIC18F4431-I/P's Power Control PWM for AC induction or BLDC motor commutation and the nanoWatt Sleep mode for overnight standby. The 5 V supply matches common HVAC control board rails, and the industrial temperature range handles rooftop and basement enclosures. The USART supports BACnet MS-TP or Modbus RTU communication with the building automation system, while the MSSP port can drive a local I2C sensor cluster.
Recommended
Uninterruptible Power Supply (UPS) Control
In small-line UPS or DC microgrid battery management, the PIC18F4431-I/P samples battery voltage and current through its 10-bit A/D, drives a half-bridge inverter via the Power Control PWM, and coordinates state-of-charge through timer-based Coulomb counting. The 34 I/O lines are enough to manage relays, status LEDs, and front-panel buttons without an I/O expander. Compared to discrete logic implementations, the integrated PWM with fault inputs cuts BOM cost and improves safety.
Recommended
Automotive Body Control Modules
Although not AEC-Q100 qualified, the PIC18F4431-I/P appears in non-safety automotive subsystems such as body computers, seat controllers, and HVAC modules where 5 V operation and the Power Control PWM drive small DC motors. The EUSART enables LIN slave communication to a central gateway, while the MSSP drives I2C sensors. For AEC-Q100 applications, choose the PIC18F46K22-I/P or PIC18F67K40 family that share the same peripheral set.
Recommended
Smart Sensor Hubs
The PIC18F4431-I/P integrates a 9-channel A/D, two serial ports, and up to 6 PWM outputs in a single 40-pin PDIP, making it a compact hub for industrial sensor arrays. Combined with external SPI or I2C sensors, the MCU can sample multiple transducers, run local averaging, and forward processed data over Modbus. The 40-pin PDIP through-hole package simplifies hand-soldered prototype assembly and field-replaceable modules.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4431-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4531-I/P | PIC18F4439-I/P | PIC18F46K22-I/P | PIC18F452-I/P | PIC18F442-I/P | PIC18F4410-I/P | PIC18F4320-I/P |
|---|---|---|---|---|---|---|---|---|
| Package | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) | DIP-40 (PDIP) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash (KB) | 16 | 32 | 16 | 64 | 32 | 16 | 16 | 8 |
| RAM (bytes) | 768 | 1536 | 768 | 3896 | 1536 | 768 | 768 | 256 |
| Max CPU Speed | 40 MHz | 40 MHz | 40 MHz | 64 MHz | 40 MHz | 40 MHz | 16 MHz | 40 MHz |
| PWM Channels | 6 (Power Control PWM) | 6 (Power Control PWM) | 6 (Power Control PWM) | 5 (CCP/ECCP) | 2 (CCP) | 2 (CCP) | 1 (CCP) | 2 (CCP) |
| A/D Channels | 9 (10-bit) | 11 (10-bit) | 9 (10-bit) | 14 (10-bit) | 8 (10-bit) | 4 (10-bit) | 8 (10-bit) | 8 (10-bit) |
| VDD Range | 4.2 to 5.5 V | 4.2 to 5.5 V | 4.2 to 5.5 V | 1.8 to 5.5 V | 4.2 to 5.5 V | 4.2 to 5.5 V | 2.0 to 5.5 V | 4.2 to 5.5 V |
Key Differentiators
- Integrated Power Control PWM with hardware fault inputs (vs PIC18F452-I/P)
- Larger A/D channel count (vs PIC18F442-I/P)
- Drop-in upgrade path with 2x memory (vs PIC18F4531-I/P)
- 40 MHz performance for 10 MIPS throughput (vs PIC18F4410-I/P)
Design Notes
Place a 100 nF decoupling capacitor within 5 mm of each VDD/VSS pair (the PIC18F4431 has two VDD pins at 11/32 and two VSS pins at 12/31). Add a bulk 10 uF electrolytic at the board supply input. Keep the trace between pins 13/14 (OSC1/OSC2) short, and route the crystal case to a quiet ground island. PGD/PGC traces (RB5/RB6) must be routed away from PWM outputs to avoid debug-noise coupling.
The Power Control PWM module has dedicated configuration registers that must be unlocked in a specific sequence before writing; failure to follow the sequence locks the registers and prevents PWM output. Refer to Microchip application note AN1079 for the unlock procedure. Also note that the CCP pins (RC1/RC2) are remapped when the Power Control PWM is active - do not assume legacy CCP behavior.
The /MCLR pin (1) requires a 10 kohm pull-up to VDD; if ICSP is used, route the /MCLR/VPP trace to the programming connector without buffer circuits. In high-noise motor-drive environments, add a 100 nF cap from /MCLR to VSS and a TVS diode (e.g., PESD5V0L1BA) to clamp ESD events. Verify that the /MCLR trace is not adjacent to the PWM outputs to prevent injected faults from triggering resets.
Compliance Information
RoHS and lead-free per Microchip product page. AEC-Q100 not applicable - choose PIC18F family K-series for automotive. Conflict minerals compliance per Microchip public CMRT filings.
