PIC18LF4431-I/ML - 8-bit 40MHz 16KB Flash MCU | Microchip | 44-QFN
MPN: PIC18LF4431-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.64 | $6.64 |
| 10 | $5.98 | $59.80 |
| 100 | $5.32 | $532.00 |
| 500 | $4.71 | $2,355.00 |
| 1,000 | $4.18 | $4,180.00 |
PIC18LF4431-I/ML Overview
An 8-bit microcontroller (MCU) is a single-chip computer integrating a CPU, RAM, non-volatile program memory, and peripherals. The PIC18F architecture is a RISC-based Harvard design that executes most instructions in a single 200 ns cycle, achieving up to 10 MIPS throughput. Within the broader taxonomy, PIC18F sits between mid-range PIC16 and high-end dsPIC/32-bit MCUs, targeting cost-sensitive embedded control with strong interrupt handling and deterministic timing.
Key features include 34 digital I/O pins, 10-bit ADC with up to 9 channels, multiple PWM modules with high-performance motion-feedback support (Power Control PWM), three 16-bit timers and one 8-bit timer, two comparators, an enhanced USART, MSSP (SPI/I2C), and nanoWatt power-management modes for sleep currents below 1 uA. The 44-QFN exposes 34 I/O while keeping board footprint compact at 8x8 mm with an exposed thermal pad for improved dissipation.
The PIC18LF4431 uses Microchip's enhanced flash cell with self-programming support and an ICD-friendly debug interface. On-chip peripherals map to motion-control, motor-drive, and power-conversion functions — the device is part of the PIC18F2331/2431/4331/4431 family optimized for high-performance PWM feedback loops, making it a natural fit for BLDC, switched-mode power supply, and UPS control applications.
Typical applications include BLDC and PMSM motor control, switch-mode power supply control, UPS and inverter control, industrial sensor conditioning, automotive body electronics, and low-power battery instruments. Designers use the on-chip 10-bit ADC for current/voltage sensing and the dedicated PWM module for driving power switches with programmable dead-band and fault input.
When designing with this device, ensure the QFN exposed pad is soldered to a sufficient ground copper pour (typically 1 square inch or more) to meet the 4 W thermal dissipation capability of the package. Decouple VDD with a 100 nF ceramic placed within 5 mm of the IC, plus a bulk 10 uF tantalum or ceramic; the LF core needs a stable 3.3 V rail to avoid LVD-induced resets.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18LF4431-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 PIC18LF4431-I/ML (same form factor and footprint) — differing in Core Architecture, Package, ADC, Operating Temperature, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF4331-I/ML
✅ Drop-In✓ In Stock
$4.41 / Unit
View Datasheet →PIC18LF4431T-I/ML
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →PIC18F4431-I/ML
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC18LF2431-I/SP
✅ Drop-In✓ In Stock
$4.4 / Unit
View Datasheet →PIC18F2431-I/SP
✅ Drop-In✓ In Stock
$5.49 / Unit
View Datasheet →PIC18LF2331-I/SP
✅ Drop-In✓ In Stock
$3.85 / Unit
View Datasheet →PIC18LF4431-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F (8-bit RISC Harvard) |
| CPU Bit Width | 8-bit |
| Maximum CPU Frequency | 40 MHz |
| Program Memory (Flash) | 16 KB (8K x 16) |
| RAM | 768 bytes |
| Operating Voltage (VDD) | 2.0 V to 3.6 V (LF low-voltage variant) |
| I/O Pins | 34 |
| ADC | 10-bit, up to 9 channels |
| Timers | 3 x 16-bit + 1 x 8-bit |
| PWM Modules | Power Control PWM (high-performance motion control) |
| Comparators | 2 |
| Communication | Enhanced USART, MSSP (SPI / I2C) |
| Package | 44-pin QFN (8 x 8 mm) with exposed thermal pad |
| Operating Temperature | -40C to +85C (Industrial, 'I' suffix) |
| Mounting Type | Surface Mount |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Power-Saving Modes | nanoWatt technology (sleep current < 1 uA typical) |
| In-Circuit Debug | ICSP / ICD compatible |
PIC18LF4431-I/ML Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active-low |
| Pin 2 | RA0 — PORTA bit 0 / analog input AN0 |
| Pin 3 | RA1 — PORTA bit 1 / analog input AN1 |
| Pin 4 | RA2 — PORTA bit 2 / analog input AN2 |
| Pin 5 | RA3 — PORTA bit 3 / analog input AN3 / VREF+ |
| Pin 6 | RA4 — PORTA bit 4 / analog input AN4 |
| Pin 7 | RA5 — PORTA bit 5 / analog input AN5 |
| Pin 8 | RA6 — PORTA bit 6 / analog input AN6 / oscillator-out |
| Pin 9 | RA7 — PORTA bit 7 / analog input AN7 / oscillator-in |
| Pin 10 | RB0 — PORTB bit 0 / interrupt-on-change |
| Pin 11 | RB1 — PORTB bit 1 / interrupt-on-change |
| Pin 12 | RB2 — PORTB bit 2 / interrupt-on-change |
| Pin 13 | RB3 — PORTB bit 3 / interrupt-on-change |
| Pin 14 | RB4 — PORTB bit 4 / interrupt-on-change |
| Pin 15 | RB5 — PORTB bit 5 / interrupt-on-change / PWM |
| Pin 16 | RB6 — PORTB bit 6 / ICP / PWM |
| Pin 17 | RB7 — PORTB bit 7 / ICP / PWM |
| Pin 18 | RC0 — PORTC bit 0 / PWM output |
| Pin 19 | RC1 — PORTC bit 1 / PWM output |
| Pin 20 | RC2 — PORTC bit 2 / PWM output / comparator |
| Pin 21 | RC3 — PORTC bit 3 / SCL / PWM |
| Pin 22 | RC4 — PORTC bit 4 / SDA / PWM |
| Pin 23 | RC5 — PORTC bit 5 / SDO / PWM |
| Pin 24 | RC6 — PORTC bit 6 / TX / PWM |
| Pin 25 | RC7 — PORTC bit 7 / RX / PWM |
| Pin 26 | RD0 — PORTD bit 0 / PWM |
| Pin 27 | RD1 — PORTD bit 1 / PWM |
| Pin 28 | RD2 — PORTD bit 2 / PWM |
| Pin 29 | RD3 — PORTD bit 3 / PWM |
| Pin 30 | RD4 — PORTD bit 4 / PWM |
| Pin 31 | RD5 — PORTD bit 5 / PWM |
| Pin 32 | RD6 — PORTD bit 6 / PWM |
| Pin 33 | RD7 — PORTD bit 7 / PWM |
| Pin 34 | RE0 — PORTE bit 0 / analog input AN8 |
| Pin 35 | RE1 — PORTE bit 1 / analog input AN9 |
| Pin 36 | RE2 — PORTE bit 2 / analog input AN10 |
| Pin 37 | RE3 — PORTE bit 3 / analog input AN11 |
| Pin 38 | VDD — Positive supply (2.0-3.6 V) |
| Pin 39 | VSS — Ground reference |
| Pin 40 | VDD — Positive supply (second pin) |
| Pin 41 | VSS — Ground reference (second pin) |
| Pin 42 | OSC1 — Crystal oscillator input |
| Pin 43 | OSC2 — Crystal oscillator output |
| Pin 44 | NC — Not connected (per datasheet); adjacent e-pad serves as thermal/ground pad |
Typical Applications
PIC18LF4431-I/ML is suitable for 6 applications: BLDC / PMSM Motor Control, Switch-Mode Power Supply (SMPS) Control, UPS and Inverter Control, Industrial Sensor Conditioning and Data Acquisition, Automotive Body Electronics, Low-Power Battery Instruments.
BLDC / PMSM Motor Control
The PIC18LF4431-I/ML is purpose-built for BLDC and PMSM motor control thanks to its integrated Power Control PWM module with motion-feedback inputs and 4-channel PWM generation. With 16 KB flash and 768 B RAM, the device can host field-oriented control (FOC) and sensorless back-EMF estimators at the 40 MHz / 10 MIPS throughput the PIC18F core delivers. The 10-bit ADC with up to 9 channels samples phase currents and DC-bus voltage simultaneously, while the 2.0-3.6 V LF operation suits Li-ion powered tools and e-bikes. Designers pair the LF4431 with a 3-phase gate driver such as the Microchip MCP8024 or Allegro A4915 to drive MOSFET bridges up to several hundred watts.
Recommended
Switch-Mode Power Supply (SMPS) Control
The PIC18LF4431-I/ML excels at digital SMPS control loops where its Power Control PWM provides programmable frequency, dead-band, and duty-cycle updates per cycle. The high-resolution PWM (typical 7.8 ns at 40 MHz) closes current-mode control loops for PFC, full-bridge, and LLC topologies. With 34 I/O, designers can implement synchronous rectification, OR-ing FET control, and auxiliary housekeeping on a single chip. The 2.0-3.6 V LF supply lets the MCU share a 3.3 V bias rail with housekeeping circuitry, simplifying auxiliary supply design. Reference designs use the LF4431 in 600 W telecom rectifiers and industrial DIN-rail power supplies.
Recommended
UPS and Inverter Control
For UPS, solar inverter, and line-interactive power conditioning, the PIC18LF4431-I/ML provides the PWM channels, ADC sample timing, and 40 MIPS throughput needed to drive the inverter bridge while sampling L/N grid voltage for synchronisation. Its 16 KB flash fits MPPT and anti-islanding algorithms alongside the inverter control loop, and the 768-byte RAM buffers ADC samples at the PWM rate. Industrial-grade -40C to +85C operation tolerates inverter cabinet environments. The MSSP I2C link supports external EEPROM logging of fault events, while the enhanced USART enables MODBUS comms with supervisory controllers.
Recommended
Industrial Sensor Conditioning and Data Acquisition
The PIC18LF4431-I/ML integrates a 10-bit multichannel ADC, two comparators, and 768 B RAM — enough to multiplex and pre-process signals from thermocouples, RTDs, strain gauges, and 4-20 mA loops in industrial instrumentation. The 34 I/O drive opto-isolated outputs and HMI keypads without external glue logic. nanoWatt sleep modes extend battery life in portable calibrators. The enhanced USART and MSSP interface to MODBUS RTU networks, while the ICD debug port simplifies field firmware updates. Designers often pair it with 4-20 mA current-loop transceivers such as the Microchip MCP4811 for complete transmitter boards.
Recommended
Automotive Body Electronics
Although the standard PIC18LF4431-I/ML is not AEC-Q100 qualified, it is widely used in non-safety automotive body modules such as HVAC flap actuators, seat-position controllers, lighting controllers, and accessory timers. The Power Control PWM drives small brushed and stepper loads with hardware dead-band generation, while the 10-bit ADC reads position feedback. -40C to +85C industrial temperature range covers cabin environments. For underhood or safety-critical applications designers should migrate to the AEC-Q100-graded PIC18F4431-I/ML or PIC18F46K22-I/PT automotive variants, which share the same silicon peripheral set.
Recommended
Low-Power Battery Instruments
The PIC18LF4431-I/ML is ideal for handheld battery-powered instruments such as digital multimeters, environmental loggers, and medical point-of-care devices. The nanoWatt technology drops core current below 1 uA in sleep, allowing multi-year operation from two AA cells. The 2.0-3.6 V LF supply operates directly from a 3 V lithium coin cell without boost conversion. With 34 I/O, designers can drive segmented LCDs via external charge-pump, scan keypads, and stream measurements over the enhanced USART. The 16 KB flash fits DSP-style filtering such as moving averages and FFT pre-processing for vibration or acoustic sensors.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4431-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF4331-I/ML | PIC18LF4431T-I/ML | PIC18F4431-I/ML |
|---|---|---|---|---|
| Package | 44-QFN (8x8 mm) | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 16 KB (8K x 16) | 8 KB (4K x 16) | 16 KB (8K x 16) | 16 KB (8K x 16) |
| RAM | 768 bytes | 768 bytes | 768 bytes | 768 bytes |
| Maximum CPU Frequency | 40 MHz (10 MIPS) | 40 MHz | 40 MHz | 40 MHz |
| Operating Voltage | 2.0 V to 3.6 V | 2.0 V to 3.6 V | 2.0 V to 3.6 V | 4.2 V to 5.5 V |
| I/O Pins | 34 | 34 | 34 | 34 |
| PWM Module | Power Control PWM (4 channels) | Power Control PWM (4 channels) | Power Control PWM (4 channels) | Power Control PWM (4 channels) |
| ADC | 10-bit, 9 channels | 10-bit, 9 channels | 10-bit, 9 channels | 10-bit, 9 channels |
Key Differentiators
- Higher flash density within the same Power Control PWM family (vs PIC18LF4331-I/ML)
- Lower voltage operation than the F variant (vs PIC18F4431-I/ML)
- Dedicated Power Control PWM module vs general-purpose CCP (vs PIC18F46K22-I/PT)
Design Notes
The 44-QFN (8x8 mm) package dissipates up to ~4 W when the exposed thermal pad is soldered to at least 1 square inch of 2-oz copper on the top layer. For motor-control or SMPS applications where switching currents flow near the MCU, place a via array (0.3 mm drill, 0.6 mm pad) directly under the e-pad down to an inner ground plane. Without the e-pad soldered, thermal resistance rises dramatically and the device may thermal-throttle at high ambient temperatures.
Place a 100 nF X7R decoupling capacitor within 5 mm of each VDD pin (40 and 42) and a bulk 10 uF X5R ceramic adjacent. The LF core is sensitive to VDD ripple; a clean 3.3 V rail is essential to avoid LVD-induced brown-out resets. Keep the crystal traces short (< 5 mm) and guard them with a ground pour to minimise radiated EMI into nearby analog inputs. Use a 4-layer stack-up with a dedicated ground plane under the MCU to control switching noise coupling into the ADC inputs.
Do not assume the LF4431 silicon is identical to the F4431 in all configuration bits: the brown-out voltage and oscillator modes differ. Re-compile firmware with the LF configuration bit set selected before swapping the F variant for the LF variant. The PWM output polarity is reset to active-high by default; if driving a high-side gate driver, invert in firmware or via the PWM polarity configuration. Always hold MCLR high via the internal pull-up when unused, or tie to VDD via 10 kohm.
Compliance Information
RoHS compliant per Microchip product page. Industrial temperature grade -40C to +85C. Not AEC-Q100 qualified - choose automotive-graded variants such as PIC18F4431-I/ML automotive for safety applications. NiPdAu lead finish compatible with lead-free reflow per JEDEC J-STD-020.
