PIC18LF2539-I/SP - 8-Bit 40MHz MCU 24KB Flash 28-SPDIP | Microchip
MPN: PIC18LF2539-I/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.88 | $28.80 |
| 100 | $2.55 | $255.00 |
| 500 | $2.3 | $1,150.00 |
| 1,000 | $2.1 | $2,100.00 |
PIC18LF2539-I/SP Overview
An 8-bit microcontroller (MCU) is a programmable single-chip processor that combines a CPU, non-volatile program memory (Flash/ROM), volatile data memory (RAM), and peripheral interfaces on one die. PIC18 devices sit within a hierarchy of microcontroller architectures: PIC10/12/14/16/18 family -> 8-bit MCU class -> microcontroller -> embedded IC -> semiconductor. The PIC18 architecture is the high-end 8-bit line of Microchip's portfolio, featuring a 16-bit instruction word for improved code density, hardware multiplier for DSP-style operations, and up to 16 MIPS execution speed.
Key specifications include 40 MHz maximum clock with 10 MIPS sustained throughput, 21 digital I/O pins (per Mouser listing) capable of source/sink 25 mA each, an internal 8 MHz oscillator, and Flash self-programming support via In-Circuit Serial Programming (ICSP). The -LF low-voltage variant enables direct Li-Ion battery operation without external regulation. Brown-out Reset (BOR), Power-on Reset (POR), Watchdog Timer (WDT), and an enhanced instruction set with C-compiler friendly architecture round out the core feature set.
Typical applications include industrial control (sensor conditioning via 10-bit ADC, motor control via ECCP module), automotive body electronics and HMI (HVAC, lighting), consumer appliances with user interfaces, low-power remote sensor nodes, and USB/serial-interface embedded products using the USART module. The 28-SPDIP package is selected for through-hole prototyping, breadboarding, educational platforms, and designs requiring easy rework or hand-soldering.
When designing with this device, ensure the configuration bits (fuses) and oscillator selection are correct for the chosen clock source. For low-power battery applications, take advantage of the LF voltage range and use Sleep mode with WDT or external interrupts to minimize current draw to microampere levels.
Drop-in alternatives for PIC18LF2539-I/SP — 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 PIC18LF2539-I/SP (same form factor and footprint) — differing in ADC, Mounting Type, I/O Pins, Package, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF2539T-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2539-I/SPG
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2523-I/SP
✅ Drop-In✓ In Stock
$3.6 / Unit
View Datasheet →PIC18F2539-I/SP
✅ Drop-In✓ In Stock
$3.92 / Unit
View Datasheet →PIC18F2539-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2539-I/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Enhanced Harvard) |
| Program Memory | 24 KB Flash (12K x 16) |
| RAM | 1408 bytes |
| Maximum Clock Frequency | 40 MHz |
| Instruction Throughput | 10 MIPS |
| Supply Voltage (LF variant) | 2.0 V to 5.5 V |
| I/O Pins | 21 (digital, source/sink 25 mA) |
| ADC | 10-bit integrated |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| Package Type | 28-SPDIP (Skinny Plastic DIP, through-hole) |
| Pin Count | 28 |
| Mounting Type | Through-Hole |
| In-Circuit Programming | ICSP (high-voltage and low-voltage) |
| ROM Type | Flash (self-programmable) |
| RoHS Status | Compliant |
PIC18LF2539-I/SP Pin Configuration
| Pin 1 | MCLR/VPP/RE3 — Master Clear (active low) / ICSP programming voltage / PORTE pin 3 |
| Pin 2 | RA0 — PORTA0 (digital I/O, ADC analog channel 0) |
| Pin 3 | RA1 — PORTA1 (digital I/O, ADC analog channel 1) |
| Pin 4 | RA2 — PORTA2 (digital I/O, ADC analog channel 2) |
| Pin 5 | RA3 — PORTA3 (digital I/O, ADC analog channel 3) |
| Pin 6 | RA4 — PORTA4 (digital I/O, ADC analog channel 4) |
| Pin 7 | RA5 — PORTA5 (digital I/O, ADC analog channel 5) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC2/RA6 — Oscillator output / PORTA6 digital I/O |
| Pin 10 | OSC1/RA7 — Oscillator input / PORTA7 digital I/O |
| Pin 11 | RC0 — PORTC0 (digital I/O) |
| Pin 12 | RC1 — PORTC1 (digital I/O) |
| Pin 13 | RC2 — PORTC2 (digital I/O, ECCP1) |
| Pin 14 | RC3 — PORTC3 (digital I/O, ECCP1) |
| Pin 15 | RC4 — PORTC4 (digital I/O, USB D-) |
| Pin 16 | RC5 — PORTC5 (digital I/O, USB D+) |
| Pin 17 | RC6 — PORTC6 (digital I/O, TX/CK for EUSART) |
| Pin 18 | RC7 — PORTC7 (digital I/O, RX/DT for EUSART) |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive power supply (2.0 V to 5.5 V for LF variant) |
| Pin 21 | RB0 — PORTB0 (digital I/O, INT0) |
| Pin 22 | RB1 — PORTB1 (digital I/O, INT1) |
| Pin 23 | RB2 — PORTB2 (digital I/O) |
| Pin 24 | RB3 — PORTB3 (digital I/O, ECCP2) |
| Pin 25 | RB4 — PORTB4 (digital I/O) |
| Pin 26 | RB5 — PORTB5 (digital I/O) |
| Pin 27 | RB6 — PORTB6 (digital I/O, ICSPCLK for ICSP) |
| Pin 28 | RB7 — PORTB7 (digital I/O, ICSPDAT for ICSP) |
Typical Applications
PIC18LF2539-I/SP is suitable for 7 applications: Industrial Sensor Conditioning, Battery-Powered Remote Sensor Node, Automotive Body Electronics HMI, Consumer Appliance Control, USB-to-Serial Bridge / Data Logger, Educational Platform / Prototyping Board, Home Automation Sensor Hub.
Industrial Sensor Conditioning
The PIC18LF2539-I/SP fits industrial sensor conditioning applications thanks to its integrated 10-bit ADC, 21 digital I/O, and 2.0-5.5 V operating range that handles 3.3 V sensor rails directly. The 24 KB Flash is large enough for calibration tables, linearization routines and a small command interpreter. Brown-out Reset plus industrial -40 °C to +85 °C rating handle factory floor conditions without additional supervisory hardware. Engineers typically pair it with external op-amps for thermocouple or strain-gauge front-ends.
Recommended
Battery-Powered Remote Sensor Node
The LF-prefixed 2.0-5.5 V supply range of the PIC18LF2539-I/SP lets it run directly from a single-cell Li-Ion or two AA cells, eliminating a boost/LDO regulator in low-power wireless sensor nodes. Sleep currents drop into the microampere range when peripherals are gated off, and the Watchdog Timer with internal 31 kHz oscillator keeps time-keeping duty cycle low. The 1408 bytes RAM is sufficient for tiny TCP/IP stacks, LoRaWAN sessions or BLE-beacon payload assembly with no external SRAM.
Recommended
Automotive Body Electronics HMI
In cabin body-electronics HMI such as HVAC panel controls, mirror adjusters and lighting modules, the PIC18LF2539-I/SP provides 21 source/sink 25 mA I/O to drive relays and LED matrices directly without buffers. The PIC18 enhanced instruction set and 10 MIPS throughput deliver responsive switch debounce and PWM dimming while leaving headroom for LIN-style UART protocols on the USART. Its industrial temperature rating covers cabin environments; for underhood use, choose the extended grade variant.
Recommended
Consumer Appliance Control
The 28-SPDIP through-hole package of the PIC18LF2539-I/SP is ideal for consumer appliances with hand-solderable boards and easy serviceability, including small kitchen appliances and white-goods user interfaces. The 24 KB Flash comfortably hosts state-machine control logic, soft-start ramps and user-interface state tables. With its 10-bit ADC it can read potentiometers and NTC sensors directly, while ECCP modules generate zero-cross triac-fire pulses for motor or heater regulation in 120/230 V mains systems.
Recommended
USB-to-Serial Bridge / Data Logger
With its enhanced USART and I2C/SPI peripherals, the PIC18LF2539-I/SP is widely used in serial data loggers, RS-232/RS-485 bridges and bridge-protocol converters in the lab and field. The 1408 bytes RAM and 24 KB Flash support packet buffering and small protocol stacks, while 25 mA I/O drive indicator LEDs directly. Its Flash self-programmability lets firmware be updated in the field via bootloader without removing the chip from its logger enclosure.
Recommended
Educational Platform / Prototyping Board
The PIC18LF2539-I/SP in through-hole 28-SPDIP is a staple for university microcontroller courses, hobbyist robots and breadboard prototyping because its 0.1 inch pin pitch fits standard perfboards and IC sockets. With MPLAB X IDE, XC8 compiler and a PICkit programmer, students can develop code at 10 MIPS using the C-friendly enhanced instruction set. The device's low-voltage range and integrated peripherals eliminate external regulator and glue logic, keeping the BOM minimal for first prototypes.
Recommended
Home Automation Sensor Hub
The PIC18LF2539-I/SP suits small home-automation hubs that aggregate data from multiple low-speed sensor interfaces (one-wire temperature, I2C humidity, SPI e-paper). Its 21 I/O channels drive multiple peripherals directly, and Flash self-programming enables OTA-style firmware updates triggered by a master controller. The LF voltage range supports battery-backed RTC designs for time-stamped event logging in security and energy monitoring applications across residential and small-commercial sites.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2539-I/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF2539T-I/SP | PIC18LF2539-I/SPG | PIC18LF2523-I/SP | PIC18F2539-I/SP | PIC18F2539-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP | 28-SPDIP (same) | 28-SPDIP (same) | 28-SPDIP (same) | 28-SPDIP (same) | 28-SOIC (surface-mount footprint) |
| Program Memory (Flash) | 24 KB | 24 KB | 24 KB | 16 KB | 24 KB | 24 KB |
| RAM | 1408 bytes | 1408 bytes | 1408 bytes | 1536 bytes | 1408 bytes | 1408 bytes |
| Maximum Clock | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage Range (LF vs F) | 2.0 V to 5.5 V (LF) | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V |
| I/O Pins | 21 | 21 | 21 | 21 | 21 | 23 (SO-28 has 2 more GPIO) |
| ADC Channels | 10-bit integrated | 10-bit integrated | 10-bit integrated | 10-bit integrated | 10-bit integrated | 10-bit integrated |
| Temperature Grade | Industrial -40 °C to +85 °C | Industrial -40 °C to +85 °C | Industrial -40 °C to +85 °C | Industrial -40 °C to +85 °C | Industrial -40 °C to +85 °C | Industrial -40 °C to +85 °C |
| Pricing (1 pc, approximate, as of 2026-09-28) | $3.10 - $3.20 | Similar | Similar | Slightly lower | Similar | Similar |
Key Differentiators
- Wider voltage operating range than the F variant (vs PIC18F2539-I/SP)
- Larger program memory than PIC18LF2523-I/SP (vs PIC18LF2523-I/SP)
- Through-hole SPDIP package ideal for prototyping (vs PIC18F2539-I/SO)
Design Notes
This part uses an internal 5 V or 3.3 V regulator that draws current from the VDD pin. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of pin 20, plus a bulk 10 µF tantalum or aluminum polymer on the main supply rail. If the design sources from a switching converter, add a ferrite bead and 10 µF cap to suppress switching noise from corrupting the internal regulator reference. Estimated: VDD current draw at 40 MHz is approximately 16 mA at 5 V from the datasheet DC characteristics.
Place the decoupling capacitor as close to the VDD/VSS pins as physically possible on both pin pairs - the high-frequency transient current path during clock-edge transitions is short and wide. Route the crystal traces (OSC1/OSC2) symmetrically to the part pins with a ground guard trace around them. Keep the ICSP programming header (RB6/RB7/MCLR) physically accessible to avoid removing the MCU for production programming.
Estimated: At 40 MHz operation with all peripherals enabled, the PIC18LF2539-I/SP draws roughly 16-25 mA from a 5 V supply, dissipating only 80-125 mW - well within the SPDIP thermal envelope (theta_JA approximately 80 °C/W for through-hole DIP), so no heatsink is needed. Junction temperature rise above 25 °C ambient is 6-10 °C. If Sleep mode is used for power saving, the LVD/BOR module may still draw a few hundred µA which should be considered in battery-life calculations.
Do not forget to configure the configuration bits (fuses) for the desired oscillator, BOR threshold, watchdog enable and code protection. Configuration bits are read at every reset and ignoring them causes bootloader or startup failures. Avoid tying ICSPDAT/ICSPCLK directly to high-current loads - these pins are 5 V tolerant but lack 25 mA drive strength and any shared load can break programming. Finally, always budget watchdog timer reset periods correctly when using long algorithm loops.
Compliance Information
RoHS and REACH compliant per Microchip material declarations; not AEC-Q100 qualified - for automotive applications requiring AEC-Q100 grade, choose a specifically qualified part number.
