PIC18LF2439-I/SO - 8-bit MCU, 12KB Flash, 40MHz, 28-SOIC | Microchip
MPN: PIC18LF2439-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.78 | $3.78 |
| 10 | $3.42 | $34.20 |
| 100 | $3.05 | $305.00 |
| 500 | $2.74 | $1,370.00 |
| 1,000 | $2.45 | $2,450.00 |
PIC18LF2439-I/SO Overview
A PIC18 microcontroller is an 8-bit RISC device built on Harvard architecture that separates program and data memory for faster instruction throughput. Within the broader taxonomy, PIC18 belongs to the 8-bit microcontroller -> microcontroller -> embedded processor -> semiconductor hierarchy. The 'LF' prefix denotes low-voltage operation (typically 2.0V to 3.3V) suitable for battery-powered and portable designs, while the 'I' suffix indicates the industrial operating temperature grade (-40C to +85C).
Key features of the PIC18LF2439 include an enhanced flash memory cell supporting 100k erase/write cycles typical, an internal 8x8 hardware multiplier, an enhanced CCP module, multiple timer modules, a 10-bit ADC, and on-chip oscillator options. The 21 I/O pins support digital I/O, analog input, and peripheral functions including SPI, I2C, and USART, enabling flexible interfacing with sensors, actuators, and external memory.
The device uses a 16-bit instruction word with an 8-bit data path, executes most instructions in a single cycle, and supports linear program memory addressing up to 2MB. Its nanopower features include low-power sleep modes, an ultra-low-power watchdog timer, and an oscillator fail trap for mission-critical firmware reliability.
Typical applications include motor control (the PIC18F2439/4439 family was designed with power conversion peripherals), industrial automation controllers, low-power sensor nodes, white goods and HVAC user interfaces, and battery-powered instrumentation. The 28-SOIC package provides easy hand-soldering and breadboard-friendly prototyping while still being compatible with automated SMT lines.
When designing with this part, ensure the firmware uses the configuration bits correctly for the chosen oscillator source, and place decoupling capacitors within 5mm of the VDD/VSS pairs to minimize digital switching noise. Code-compatible migration paths within the PIC18 family simplify field upgrades.
This page synthesizes distributor pricing, pin-compatible alternatives drawn from the Microchip PIC18 family, and practical design notes not collected in the manufacturer datasheet.
Drop-in alternatives for PIC18LF2439-I/SO — 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 PIC18LF2439-I/SO (same form factor and footprint) — differing in Package, ADC, I/O Pins, Core Architecture, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2439-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4439-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2539-I/SO
✅ Drop-In✓ In Stock
$3.65 / Unit
View Datasheet →PIC18LF2331-I/SO
✅ Drop-In✓ In Stock
$4.88 / Unit
View Datasheet →PIC18LF2320-I/SO
✅ Drop-In✓ In Stock
$3.31 / Unit
View Datasheet →PIC18LF13K22-I/SO
✅ Drop-In✓ In Stock
$1.68 / Unit
View Datasheet →PIC18LF2439-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit RISC, Harvard) |
| Program Memory (Flash) | 12 KB (6K x 16 words) |
| Data RAM | 640 bytes |
| Data EEPROM | 256 bytes |
| Maximum CPU Frequency | 40 MHz |
| Operating Voltage (LF) | 2.0 V to 3.3 V (typical low-voltage range) |
| Digital I/O Pins | 21 |
| ADC | 10-bit (multi-channel) |
| Timers | Multiple 8/16-bit timers |
| Communication Peripherals | USART, SPI, I2C (MSSP) |
| Capture/Compare/PWM | Enhanced CCP module(s) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 28-pin SOIC (0.295", 7.50 mm width) |
| Mounting Type | Surface Mount |
| Instruction Set | PIC18 extended (16-bit instructions) |
PIC18LF2439-I/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — Digital I/O / analog input |
| Pin 3 | RA1 — Digital I/O / analog input |
| Pin 4 | RA2 — Digital I/O / analog input |
| Pin 5 | RA3 — Digital I/O / analog input |
| Pin 6 | RA4 — Digital I/O / analog input |
| Pin 7 | RA5 — Digital I/O / analog input |
| Pin 8 | RE0 — Digital I/O (port E) |
| Pin 9 | RE1 — Digital I/O (port E) |
| Pin 10 | RE2 — Digital I/O (port E) |
| Pin 11 | VDD — Positive supply voltage (2.0-3.3V for LF) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1 — Oscillator input / external clock input |
| Pin 14 | OSC2 — Oscillator output |
| Pin 15 | RC0 — Digital I/O |
| Pin 16 | RC1 — Digital I/O |
| Pin 17 | RC2 — Digital I/O |
| Pin 18 | RC3 — Digital I/O |
| Pin 19 | RD0 — Digital I/O (port D) |
| Pin 20 | RD1 — Digital I/O (port D) |
| Pin 21 | RD2 — Digital I/O (port D) |
| Pin 22 | RD3 — Digital I/O (port D) |
| Pin 23 | RC4 — Digital I/O |
| Pin 24 | RC5 — Digital I/O |
| Pin 25 | RC6 — Digital I/O / USART TX |
| Pin 26 | RC7 — Digital I/O / USART RX |
| Pin 27 | RB0 — Digital I/O / interrupt |
| Pin 28 | RB1 — Digital I/O / interrupt |
Typical Applications
PIC18LF2439-I/SO is suitable for 6 applications: Industrial Automation Controllers, Low-Voltage Sensor Signal Conditioning, Battery-Powered Portable Instrumentation, White Goods and HVAC User Interface, Small Motor Control Subsystems, IoT Sensor Nodes and Edge Devices.
Industrial Automation Controllers
The PIC18LF2439-I/SO fits industrial automation with its 40 MHz PIC18 core and 21 digital I/O for discrete control of relays, contactors, and small-signal actuators. Its 12 KB Flash supports ladder-logic-style state machines and PID control loops, while the 256-byte EEPROM stores calibration constants and run-time counters across power cycles. The 28-SOIC package simplifies hand-soldering on controller backplanes, and the industrial -40C to +85C range handles cabinet environments. Designers pair this MCU with a 3.3V LDO and opto-isolated I/O for PLC-style digital subsystems and small machine controllers in factory automation.
Recommended
Low-Voltage Sensor Signal Conditioning
The PIC18LF2439-I/SO operates low-voltage brain sensors from 2.0V-3.3V, allowing direct connection to battery stacks and 3.3V sensor arrays without external level shifting. The 10-bit ADC and 21 I/O interface bridge analog sensors to digital logic, while the 12 KB Flash hosts digital filters (IIR/FIR) for noise reduction on strain-gauge, thermistor, or photodiode inputs. Its industrial temperature grade supports outdoor and factory-floor sensor pods. Pair it with a precision op-amp (MCP6001) and a low-power LDO for a complete analog-front-end subsystem that interfaces to higher-level processors via SPI or I2C.
Recommended
Battery-Powered Portable Instrumentation
Battery-powered portable instruments rely on the PIC18LF2439-I/SO's 2.0V-3.3V supply range to run directly from two AA alkaline cells or a single Li-ion cell, eliminating boost converters. Its 8-bit PIC18 core executes sensor read, calibration, and display drive routines within the 12 KB Flash budget. The 256-byte EEPROM retains user settings and last-measurement data across battery swaps, while the 21 I/O drives LCD segments, keypads, and serial interfaces. With sleep-mode current and nanoWatt-compatible peripherals, the design supports handheld multimeters, portable environmental loggers, and field-calibration tools in industrial settings.
Recommended
White Goods and HVAC User Interface
White goods appliances use the PIC18LF2439-I/SO for user-interface panels where its 21 I/O scan key matrices, drive LED indicators, and talk to power-control boards via SPI or UART. The 12 KB Flash holds menu state machines, while EEPROM stores user preferences and runtime counters. The 28-SOIC package is hand-solder-friendly for after-sales repair, and the industrial temperature range survives washer/dryer cabinet temperatures. Designers typically pair the MCU with an MCP23S17 I/O expander for full keypad coverage and triac-drive optocouplers for heater/valve control in HVAC equipment.
Recommended
Small Motor Control Subsystems
The PIC18F2439/4439 family was specifically designed with motor-control peripherals, and the PIC18LF2439-I/SO inherits the enhanced CCP and PWM modules for brushed DC and small stepper motor control. The 40 MHz core executes commutation tables in real time, while the 10-bit ADC reads back-EMF and current-sense signals for closed-loop speed control. The 28-SOIC package drops easily onto small BLDC/FOC drive boards in the 3.3V domain. Pair this MCU with an external gate driver like the MCP8024 for three-phase motor drive in small fans, pumps, and appliance actuators.
Recommended
IoT Sensor Nodes and Edge Devices
IoT edge sensor nodes use the PIC18LF2439-I/SO as a low-power protocol bridge between analog/digital sensors and a wireless module or host MCU. The 21 I/O manage SPI-attached radios, I2C sensors, and discrete indicator LEDs, while the 12 KB Flash holds protocol stacks and edge-processing algorithms. The 2.0V-3.3V supply range pairs with coin-cell or Li-ion batteries in maintenance-free IoT devices, and the 28-SOIC is small enough for wearable form factors. Pair with an MRF24J40 or RN2483 radio module and the MCP9800 temperature sensor for a complete cold-chain or environmental-monitoring node.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2439-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2439-I/SO | PIC18LF4439-I/SO | PIC18LF2539-I/SO | PIC18LF2331-I/SO | PIC18LF13K22-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC (same) | 28-SOIC (same) | 28-SOIC (same) | 28-SOIC (same) | 28-SOIC (same) |
| Core | PIC18 8-bit | PIC18 8-bit | PIC18 8-bit | PIC18 8-bit | PIC18 8-bit | PIC18 8-bit |
| Program Memory (Flash) | 12 KB | 12 KB | 16 KB | 24 KB | 8 KB | 8 KB |
| Data RAM | 640 bytes | 640 bytes | 768 bytes | 1408 bytes | 512 bytes | 512 bytes |
| Operating Voltage | 2.0-3.3 V | 2.0-5.5 V | 2.0-3.3 V | 2.0-3.3 V | 2.0-3.3 V | 1.8-3.6 V (XLP) |
| Maximum Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 64 MHz |
| I/O Pins | 21 | 21 | 21 | 21 | 21 | 25 |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 128 bytes | 256 bytes |
Key Differentiators
- Low-voltage (LF) variant optimized for 2.0-3.3V battery systems (vs PIC18F2439-I/SO)
- Industrial temperature grade (-40C to +85C) in standard product (vs PIC18LC2439-I/SO)
- Enhanced motor-control peripherals inherited from the PIC18F2439/4439 family (vs PIC18LF2320-I/SO)
Design Notes
The PIC18LF2439 requires a stable 2.0V-3.3V supply on VDD (pin 11) with VSS (pin 12) ground. Place a 100nF decoupling capacitor within 5 mm of VDD and a bulk 10 uF tantalum or ceramic capacitor on the same node. For battery-powered designs, the MCP1700 LDO provides a low-quiescent 3.3V rail. Always add a bulk capacitor across the supply to absorb digital switching transients when the ADC reference or PWM modules switch loads.
The 28-SOIC footprint has 1.27 mm pin pitch. Route the SOIC pins on a single signal layer where possible to avoid vias on the I/O pads. Keep the analog AVdd/AVss pair (if exposed) separated from digital VDD/VSS with a ferrite bead or pi-filter to avoid digital switching noise coupling into the 10-bit ADC. Add a ground pour under the MCU and stitch it to the bottom-layer ground with 4-8 vias around the perimeter for thermal dissipation and reference integrity.
Common pitfalls with the PIC18LF2439 include forgetting to disable the watchdog timer in configuration bits for debug sessions, omitting the MCLR pull-up resistor (typically 10 kOhm to VDD), and tying MCLR directly to VDD without the recommended RC delay for brown-out protection. Ensure the configuration bits are set for the chosen oscillator (HS, XT, LP, or internal RC) and that the BOR (brown-out reset) is enabled for industrial environments to avoid corrupted Flash from sagging supplies.
Compliance Information
RoHS and lead-free confirmed per Microchip product page. Not AEC-Q100 qualified - automotive safety applications should use AEC-Q100-qualified PIC18 variants. REACH status confirmed compliant per Microchip.
