PIC18LF4439T-I/ML - 8-bit MCU, 12KB Flash, 40MHz, 44-QFN | Microchip
MPN: PIC18LF4439T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.18 | $6.18 |
| 10 | $5.79 | $57.90 |
| 100 | $5.41 | $541.00 |
| 500 | $4.85 | $2,425.00 |
| 1,000 | $4.36 | $4,360.00 |
PIC18LF4439T-I/ML Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, RAM, peripherals, and I/O on one die. The PIC18F family sits between Microchip's baseline PIC16 and the 16-bit dsPIC families, targeting applications that need more code space, more peripherals, and deterministic interrupt handling than an 8-bit baseline MCU but where cost and power must remain low. Within the power IC taxonomy, an MCU is a digital logic IC; within the broader semiconductor hierarchy it is part of the embedded computing category.
Key features of the PIC18LF4439T-I/ML include a 40 MHz internal/external clock, hardware Multiply instruction, 16-bit wide instructions with an 8-bit data path, and 31-level hardware stack. The device integrates two CCP modules, one Enhanced CCP (ECCP) module for advanced PWM and full-bridge motor control, a USART with LIN support, an MSSP for SPI/I2C, and a 10-bit ADC with up to 8 channels. The nanoWatt Technology provides multiple idle/sleep modes that drop quiescent current below 1 microampere in deep sleep, enabling battery-friendly designs.
The LF silicon process is optimized for low-voltage operation down to 2.0V, making the LF4439 suitable for 2x AA battery cells or single Li-ion applications with a 3.3V regulator. The 44-pin QFN (ML) package offers a compact 8x8 mm footprint with an exposed thermal pad for improved heat dissipation during sustained 40 MHz operation. Programming and in-circuit debugging are supported through Microchip's ICSP (In-Circuit Serial Programming) interface and the MPLAB ICD debugger family.
Typical applications for the PIC18LF4439T-I/ML include motor control (BLDC, brushed DC, stepper) thanks to the ECCP full-bridge PWM, white goods and appliance control panels, low-power sensor nodes, USB-to-UART bridges where the USART is paired with an external USB transceiver, and industrial control requiring 5V-tolerant I/O. The part is particularly well suited to designs migrating from PIC16 to PIC18 without changing the supply voltage rail.
When designing with this part, ensure the QFN exposed pad is soldered to a sufficient copper area (typically 1 square inch) for thermal dissipation. Decoupling must include a 100 nF ceramic on each power pin within 2 mm of the package, and a bulk 4.7-10 uF tantalum or ceramic on the main VDD rail. The configuration bits should be reviewed carefully to set the oscillator mode, watchdog state, and code protection before programming.
This page consolidates distributor pricing, drop-in pin-compatible alternatives from Microchip's PIC18 family, and practical design notes that go beyond what the manufacturer datasheet alone provides.
Drop-in alternatives for PIC18LF4439T-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 PIC18LF4439T-I/ML (same form factor and footprint) — differing in ADC, Package, Core Architecture, I/O Pins, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4439T-I/ML
✅ Drop-In✓ In Stock
$3.32 / Unit
View Datasheet →PIC18LF4439-I/ML
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC18LF4331T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4321-I/ML
✅ Drop-In✓ In Stock
$4.43 / Unit
View Datasheet →PIC18LF4320T-I/ML
✅ Drop-In✓ In Stock
$4.68 / Unit
View Datasheet →PIC18LF4221-I/ML
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC18LF4439T-I/ML Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit RISC |
| Series | PIC18F (PIC18LF4439) |
| Program Memory Size | 12 KB (6K x 16) Flash |
| RAM Size | 640 bytes |
| EEPROM Size | 256 bytes |
| Maximum CPU Speed | 40 MHz |
| Supply Voltage (Vdd) | 2.0 V to 5.5 V |
| I/O Pins | 36 |
| ADC | 10-bit, up to 8 channels |
| PWM Modules | 2x CCP + 1x ECCP (full-bridge capable) |
| Communication | 1x USART (LIN), 1x MSSP (SPI/I2C) |
| Timers | 4 (Timer0/1/2/3) |
| Package | 44-QFN (8x8 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Programming/Debug | ICSP, ICD |
| Power-Saving Modes | nanoWatt Technology (Run/Idle/Sleep) |
PIC18LF4439T-I/ML Pin Configuration
| Pin 1 | RB3/CCP2 — Digital I/O RB3 / Capture-Compare-PWM2 |
| Pin 2 | RB4 — Digital I/O RB4 |
| Pin 3 | RB5/PGM — Digital I/O RB5 / ICSP program pin |
| Pin 4 | RB6/PGC — Digital I/O RB6 / ICSP clock |
| Pin 5 | RB7/PGD — Digital I/O RB7 / ICSP data |
| Pin 6 | Vdd — Positive supply voltage (2.0V to 5.5V) |
| Pin 7 | RA0/AN0 — Digital I/O RA0 / analog input AN0 |
| Pin 8 | RA1/AN1 — Digital I/O RA1 / analog input AN1 |
| Pin 9 | RA2/AN2/Vref- — Digital I/O RA2 / AN2 / ADC Vref- |
| Pin 10 | RA3/AN3/Vref+ — Digital I/O RA3 / AN3 / ADC Vref+ |
| Pin 11 | RA4/T0CKI — Digital I/O RA4 / Timer0 clock input |
| Pin 12 | RA5/AN4/SS — Digital I/O RA5 / AN4 / SPI slave select |
| Pin 13 | OSC1/RA7 — Crystal oscillator input / digital I/O RA7 |
| Pin 14 | OSC2/RA6 — Crystal oscillator output / digital I/O RA6 |
| Pin 15 | Vss — Ground reference |
| Pin 16 | RC0/T1OSO — Digital I/O RC0 / Timer1 oscillator output |
| Pin 17 | RC1/T1OSI — Digital I/O RC1 / Timer1 oscillator input |
| Pin 18 | RC2/CCP1 — Digital I/O RC2 / Capture-Compare-PWM1 |
| Pin 19 | RC3/SCK/SCL — Digital I/O RC3 / SPI clock / I2C clock |
| Pin 20 | RC4/SDI/SDA — Digital I/O RC4 / SPI data in / I2C data |
| Pin 21 | RC5/SDO — Digital I/O RC5 / SPI data out |
| Pin 22 | RC6/TX/CK — Digital I/O RC6 / USART TX / USART clock |
| Pin 23 | RC7/RX/DT — Digital I/O RC7 / USART RX / USART data |
| Pin 24 | Vss — Ground reference |
| Pin 25 | RD0/PSP0 — Digital I/O RD0 / parallel slave port data 0 |
| Pin 26 | RD1/PSP1 — Digital I/O RD1 / parallel slave port data 1 |
| Pin 27 | RD2/PSP2 — Digital I/O RD2 / parallel slave port data 2 |
| Pin 28 | RD3/PSP3 — Digital I/O RD3 / parallel slave port data 3 |
| Pin 29 | RD4/PSP4 — Digital I/O RD4 / parallel slave port data 4 |
| Pin 30 | RD5/PSP5/P1B — Digital I/O RD5 / PSP5 / Enhanced PWM output P1B |
| Pin 31 | RD6/PSP6/P1C — Digital I/O RD6 / PSP6 / Enhanced PWM output P1C |
| Pin 32 | RD7/PSP7/P1D — Digital I/O RD7 / PSP7 / Enhanced PWM output P1D |
| Pin 33 | Vss — Ground reference |
| Pin 34 | RC0/FLT0 — Digital I/O RC0 / ECCP Fault input (Note: see datasheet pin map) |
| Pin 35 | RE0/RD/AN5 — Digital I/O RE0 / parallel read / AN5 |
| Pin 36 | RE1/WR/AN6 — Digital I/O RE1 / parallel write / AN6 |
| Pin 37 | RE2/CS/AN7 — Digital I/O RE2 / parallel chip select / AN7 |
| Pin 38 | RE3 — Digital I/O RE3 (input only on this device) |
| Pin 39 | AVdd — Analog supply voltage |
| Pin 40 | AVss — Analog ground |
| Pin 41 | RB0/INT0 — Digital I/O RB0 / external interrupt 0 |
| Pin 42 | RB1/INT1 — Digital I/O RB1 / external interrupt 1 |
| Pin 43 | RB2/INT2 — Digital I/O RB2 / external interrupt 2 |
| Pin 44 | MCLR/Vpp — Master Clear (reset) / programming voltage |
Typical Applications
PIC18LF4439T-I/ML is suitable for 6 applications: BLDC and Brushed DC Motor Control, White Goods and Appliance Control Panels, Low-Power Sensor Hubs and IoT Nodes, Industrial Control and 5V Logic Systems, Automotive Body and Comfort Modules, USB-to-UART and Communication Bridges.
BLDC and Brushed DC Motor Control
The PIC18LF4439T-I/ML is a strong fit for low-cost BLDC, brushed DC, and stepper motor control thanks to its Enhanced CCP module with full-bridge PWM, programmable dead-band, and 40 MHz clock for tight current-control loops. The 10-bit ADC with up to 8 channels samples back-EMF, phase current, and DC-bus voltage simultaneously, while the integrated timers handle Hall-sensor or quadrature encoder feedback. With nanoWatt Technology dropping quiescent current below 1 uA in sleep, the part supports battery-powered tools and appliances that spend most of their life idle. The 44-QFN package keeps the BOM small enough for handheld drills, fans, pumps, and small robotic actuators.
Recommended
White Goods and Appliance Control Panels
Washing machines, dishwashers, refrigerators, and microwave ovens benefit from the PIC18LF4439T-I/ML's 36 I/O pins, USART for display/keypad interfaces, and 5V-tolerant operation. The MSSP module supports SPI or I2C peripherals such as character LCDs, capacitive touch sensors, and EEPROM storage. The 12 KB Flash comfortably holds the appliance state machine plus fault diagnostics, and the 256 bytes of EEPROM store user settings through brown-out events. nanoWatt Technology enables standby power below EU Eco-Design requirements without an external RTC chip. The 44-QFN footprint is small enough for compact front-panel PCBs.
Recommended
Low-Power Sensor Hubs and IoT Nodes
The PIC18LF4439T-I/ML runs from 2.0V to 5.5V, allowing direct connection to 2x AA cells or a single Li-ion supply, and its nanoWatt Technology offers Run, Idle, and Sleep modes that drop current consumption to microampere levels. The 10-bit ADC reads temperature, humidity, and gas-sensor signals while the USART forwards them to a wireless transceiver. The 12 KB Flash holds small protocol stacks such as Modbus RTU, while 640 bytes of RAM buffers sensor data. With the LF variant supporting 2.0V low-voltage operation, sensor nodes can run on partially depleted batteries, extending service intervals. The 44-QFN provides a compact footprint for sensor modules.
Recommended
Industrial Control and 5V Logic Systems
The PIC18LF4439T-I/ML operates over the full 2.0V to 5.5V range and is well suited to 5V industrial environments where 3.3V-only MCUs require level shifters. With 36 I/O pins it can drive relays, optocouplers, and 5V logic gates directly. The MSSP and USART connect to RS485 transceivers, while the ECCP generates timing pulses for valve and actuator control. The wide operating temperature range of -40C to +85C (Industrial grade) covers most factory-floor cabinets and outdoor enclosures. The 12 KB Flash supports standard industrial protocols such as Modbus and simple CAN bridging logic.
Recommended
Automotive Body and Comfort Modules
Within automotive body controllers (window lifts, mirror adjusters, interior lighting), the PIC18LF4439T-I/ML provides 12 KB Flash, a 10-bit ADC for battery voltage monitoring, and PWM channels for motor speed and LED dimming. Although the Industrial grade (-40C to +85C) suffices for cabin applications, AEC-Q100 Grade 1 parts are required for under-hood deployment. The 40 MHz clock executes LIN slave stacks in real time, while the USART handles LIN communication. The 44-QFN exposed pad aids thermal dissipation for sustained PWM output. Engineers typically place the MCU next to local motor drivers and CAN/LIN transceivers.
Recommended
USB-to-UART and Communication Bridges
The PIC18LF4439T-I/ML acts as a USB-to-UART bridge when paired with an external USB Full-Speed transceiver such as the MCP2200 or FT232; alternatively the USART connects directly to RS-232 or RS-485 transceivers. The MSSP module implements SPI master for SD-card or external Flash, while the USART handles asynchronous serial. With 12 KB Flash and 640 bytes of RAM, the part supports small command parsers and bootloader functionality. The 44-QFN footprint is small enough to embed inside an inline cable adapter. nanoWatt sleep mode drops idle current to microamperes, allowing bus-powered or battery-powered designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4439T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4439T-I/ML | PIC18LF4439-I/ML | PIC18LF4331T-I/ML | PIC18LF4321-I/ML | PIC18LF4320T-I/ML | PIC18LF4221-I/ML |
|---|---|---|---|---|---|---|---|
| Package | 44-QFN (8x8 mm) | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 12 KB | 12 KB | 12 KB | 8 KB (-33%) | 8 KB (-33%) | 8 KB (-33%) | 4 KB (-67%) |
| RAM | 640 bytes | 640 bytes | 640 bytes | 640 bytes | 256 bytes (-60%) | 512 bytes (-20%) | 256 bytes (-60%) |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Maximum Clock | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage | 2.0V to 5.5V (LF) | 4.2V to 5.5V (F, +30% low-cut) | 2.0V to 5.5V (LF) | 2.0V to 5.5V (LF) | 2.0V to 5.5V (LF) | 2.0V to 5.5V (LF) | 2.0V to 5.5V (LF) |
| I/O Pins | 36 | 36 | 36 | 36 | 36 | 36 | 36 |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Low-voltage 2.0V operation extends battery life (vs PIC18F4439T-I/ML (F variant))
- Enhanced CCP supports full-bridge motor control (vs PIC18F4550-I/ML)
- Compact 44-QFN with exposed pad (vs PIC18LF4620-I/P (DIP-40))
- nanoWatt Technology with sub-1 uA sleep current (vs PIC18F46J11-I/PT)
Design Notes
The 44-QFN (ML) package includes an exposed thermal pad (EP) underneath the die that must be soldered to a copper pour on the PCB. Use at least 1 square inch (645 mm^2) of 2-oz copper on top and bottom layers connected by thermal vias (0.3 mm diameter, 1.2 mm pitch) for sustained 40 MHz operation. Without proper EP soldering, theta_JA rises above 50 C/W and the device can thermally throttle or fail in enclosed industrial cabinets.
Decoupling: place a 100 nF ceramic capacitor within 2 mm of every Vdd/Vss pair on the 44-QFN. Add a bulk 4.7 uF-10 uF ceramic or tantalum on the main Vdd rail. The AVdd and AVss pins serve the 10-bit ADC and should be filtered with a ferrite bead from digital Vdd plus a 100 nF + 10 uF pair. nanoWatt Technology depends on clean power; voltage ripple above 50 mV can cause spurious peripheral wake-ups in sleep mode.
The 44-QFN (ML) land pattern uses 0.5 mm pitch pads. Stencil apertures should be 1:1 with the pad for the outer pads and slightly reduced (80%) for the central thermal pad to avoid solder voiding. Reflow profile follows JEDEC J-STD-020 with peak temperature 248 C max for lead-free SAC305 paste. Avoid placing tall components within 2 mm of the QFN to ensure reliable paste release and probe access for in-circuit debugging.
Configuration bits are critical: confirm the oscillator mode (HS for >4 MHz crystal, XT for 1-4 MHz, RC for cost-sensitive) and disable the watchdog if not used. Forgetting to set the LVP bit or leaving MCLR disabled can brick the part. ICSP requires PGC (RB6) and PGD (RB7); ensure these pins are not pulled low by external circuits during programming. Always read the device errata before finalizing firmware to avoid silicon-revision-specific bugs.
The 10-bit ADC accuracy depends on clean AVdd and low-impedance reference. Place the Vref+ (RA3) and Vref- (RA2) decoupling caps within 5 mm of the pin, and route analog traces away from PWM and clock lines. For 8-channel ADC scanning at 40 MHz, the acquisition time must be set to >= 1.4 us per datasheet; violating this introduces cross-talk between channels and reduces effective resolution.
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial-grade (-40C to +85C) only - NOT AEC-Q100 qualified; for automotive choose AEC-Q100 Grade 1 PIC18 variants.
