PIC18LF4539T-I/PT - 8-Bit 40MHz MCU, 24KB FLASH, 44-TQFP | Microchip
MPN: PIC18LF4539T-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.19 | $4.19 |
| 10 | $3.85 | $38.50 |
| 100 | $3.52 | $352.00 |
| 500 | $3.18 | $1,590.00 |
| 1,000 | $2.85 | $2,850.00 |
PIC18LF4539T-I/PT Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, data memory, and peripheral interfaces on one die. PIC18F devices sit in the mid-range of Microchip's 8-bit portfolio (PIC10/12/16/18/24 families) and are widely chosen for industrial control, automotive body modules, and appliance applications where deterministic response and ease of programming outweigh raw computational throughput. The PIC18F architecture supersedes the earlier PIC16F by adding a 16-bit instruction word, larger linear addressing, and richer peripherals while preserving the original PIC instruction set.
The PIC18LF4539 includes an integrated Single-Phase Induction Motor Control Kernel, which simplifies firmware development for fan, pump, and small motor drive applications. With 32 general-purpose I/O lines, multiple timers, A/D conversion channels, and PWM/capture/compare peripherals, the device reduces external component count. Its 40MHz clock delivers 10 MIPS of processing throughput, adequate for closed-loop motor control and modest signal-processing tasks.
Typical applications include single-phase induction motor drives (fans, pumps, compressors), home appliances (washing machines, refrigerators, induction cookers), industrial control boards, sensor signal conditioning, and human-machine interface panels. The 24KB FLASH supports substantial application code with room for a bootloader or diagnostic routines, while the 1408 bytes of RAM comfortably holds stack, variables, and protocol buffers.
When designing with this part, choose the -LF variant (2.0V-3.3V) when system power is derived from a low-voltage rail such as a Li-ion cell, or step down from 5V using an LDO; the non-LF variant PIC18F4539 is required if the system runs directly from 5V. Decouple VDD/AVDD with 100nF and 10uF capacitors placed close to the pins, and reserve MCLR with the recommended 10k pull-up.
This page synthesizes distributor pricing from DigiKey and Hotenda, drop-in alternative MPNs from Microchip's PIC18 family, and practical design notes not found on a single distributor page.
Drop-in alternatives for PIC18LF4539T-I/PT — 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 PIC18LF4539T-I/PT (same form factor and footprint) — differing in Package, Timers, I/O Pins, ADC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF4539-I/PT
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC18LF4525T-I/PT
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18LF4520T-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4523T-I/PT
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →PIC18LF4523-I/PT
✅ Drop-In✓ In Stock
$5 / Unit
View Datasheet →PIC18LF4439T-I/PT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.8 / Unit
View Datasheet →PIC18LF4539T-I/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC18F |
| Maximum CPU Frequency | 40 MHz |
| Program Memory (FLASH) | 24 KB (12K x 16) |
| Data Memory (RAM) | 1408 bytes |
| I/O Pins | 32 |
| Package | 44-TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Operating Voltage (LF) | 2.0 V to 3.3 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Temperature Grade | Industrial |
| Terminal Form | Gull Wing |
| Package Code | TQFP |
| Peripherals | Single-Phase Induction Motor Control Kernel, A/D, PWM, Timers |
| RoHS Status | Compliant |
PIC18LF4539T-I/PT Pin Configuration
| Pin 1 | MCLR/VPP — Master clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / A/D reference low |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / A/D reference high |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / read control / analog input 5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / write control / analog input 6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / chip select / analog input 7 |
| Pin 11 | VDD — Positive supply voltage (2.0V-3.3V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKI/RA7 — Crystal oscillator input / external clock in / PORTA bit 7 |
| Pin 14 | OSC2/CLKO/RA6 — Crystal oscillator output / clock out / PORTA bit 6 |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM/capture/compare |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 20 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port bit 1 |
| Pin 21 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port bit 2 |
| Pin 22 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port bit 3 |
| Pin 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 25 | RC6/TX/CK — PORTC bit 6 / UART transmit / clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / UART receive / data |
| Pin 27 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 28 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port bit 5 |
| Pin 29 | RD6/PSP6/TX2 — PORTD bit 6 / Parallel Slave Port bit 6 / UART2 TX |
| Pin 30 | RD7/PSP7/RX2 — PORTD bit 7 / Parallel Slave Port bit 7 / UART2 RX |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage (2.0V-3.3V) |
| Pin 33 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 34 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 35 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 36 | RB3/INT3/CCP2A — PORTB bit 3 / external interrupt 3 / CCP2 alt |
| Pin 37 | RB4 — PORTB bit 4 |
| Pin 38 | RB5 — PORTB bit 5 |
| Pin 39 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 40 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 41 | AVDD — Analog positive supply voltage |
| Pin 42 | AVSS — Analog ground reference |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC18LF4539T-I/PT is suitable for 6 applications: Single-Phase Induction Motor Drive, Home Appliance Control Board, Ceiling Fan Speed Controller, Industrial Sensor Signal Conditioning, Human-Machine Interface (HMI) Panel, Battery-Powered Wireless Sensor Node.
Single-Phase Induction Motor Drive
The PIC18LF4539T-I/PT is purpose-built for single-phase induction motor control in fans, pumps, and small compressors. Its integrated Single-Phase Induction Motor Control Kernel offloads zero-crossing detection, phase-angle firing, and back-EMF sampling into hardware, letting firmware focus on speed/ torque setpoint tracking. The 24KB FLASH accommodates a full V/Hz or vector-control algorithm plus diagnostics, while 1408 bytes of RAM holds lookup tables and the runtime state machine. Operating from 2.0V to 3.3V aligns with low-voltage motor-rail designs when paired with an LDO, reducing switching losses in the inverter stage.
Recommended
Home Appliance Control Board
Washing machines, refrigerators, induction cookers, and rice cookers use the PIC18LF4539T-I/PT as the main controller to drive user-interface keypads, sensor inputs, and the motor-control front end. Its 32 GPIO pins easily handle 7-segment displays, rotary encoders, NTC temperature sensors, and triac-fired heaters. Industrial -40C to +85C temperature grade supports the harsh thermal environment inside an appliance cabinet. The 40MHz clock supports debounce, PID loops, and protocol stacks (UART, I2C) for inverter module communication.
Recommended
Ceiling Fan Speed Controller
The PIC18LF4539T-I/PT is a strong fit for ceiling fan remote-controlled speed regulators, where it drives a triac-based phase-angle dimmer for AC fan motors. The motor-control kernel handles zero-cross detection and adaptive firing-angle calculation, reducing DSP load on the main CPU. The 24KB FLASH supports wireless protocol stacks (RF receiver decoding, IR remapping) plus user-mode customization. Low-voltage LF operation allows direct Li-ion battery backup for the controller logic without needing a separate 5V rail.
Recommended
Industrial Sensor Signal Conditioning
Industrial 4-20mA loop-powered transmitters and bridge-sensor conditioners use the PIC18LF4539T-I/PT to digitize analog signals, perform linearization, and present a calibrated output over UART or HART. The MCU's 10-bit A/D is adequate for most transducer applications; its 32 I/O lines handle multiple sensor channels. Industrial temperature grade ensures stable operation across -40C to +85C factory-floor environments. The 24KB FLASH holds calibration tables and PID control code, while 1408 bytes RAM stores runtime filter state.
Recommended
Human-Machine Interface (HMI) Panel
Appliance and industrial HMI panels using character LCDs, keypads, and status LEDs employ the PIC18LF4539T-I/PT for menu rendering, button debouncing, and indicator driving. Its 32 I/O lines support a 4x4 keypad, a 16x2 LCD (4-bit mode), and up to 8 status LEDs with no external logic. The 24KB FLASH accommodates multilingual menus and graphics, while the LF low-voltage rating suits battery-backed UI boards. Industrial temperature grade ensures the panel survives shop-floor environments.
Recommended
Battery-Powered Wireless Sensor Node
Battery-powered wireless sensor nodes (e.g. HVAC duct sensors, irrigation moisture probes) use the PIC18LF4539T-I/PT for sensor acquisition and low-duty-cycle RF transmission. Operating from 2.0V to 3.3V aligns with two AA alkaline cells or a single Li-ion cell, eliminating the need for a boost converter and improving efficiency. The integrated sleep modes and 40MHz processing let the MCU wake, sample, transmit, and return to sleep within milliseconds - critical for multi-year battery life. 24KB FLASH supports an over-the-air firmware update bootloader.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4539T-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF4539-I/PT | PIC18LF4525T-I/PT | PIC18LF4520T-I/PT | PIC18LF4523T-I/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10) | 44-TQFP (10x10) - same | 44-TQFP (10x10) - same | 44-TQFP (10x10) - same | 44-TQFP (10x10) - same |
| FLASH Memory | 24 KB | 24 KB | 48 KB (+100%) | 32 KB (+33%) | 32 KB (+33%) |
| RAM | 1408 bytes | 1408 bytes | 1536 bytes (+9%) | 1536 bytes (+9%) | 1536 bytes (+9%) |
| Maximum Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Motor Control Kernel | Yes (Single-Phase Induction) | Yes (Single-Phase Induction) | No | No | No |
| Operating Voltage | 2.0V to 3.3V (LF) | 2.0V to 3.3V (LF) | 2.0V to 3.3V (LF) | 2.0V to 3.3V (LF) | 2.0V to 3.3V (LF) |
| A/D Resolution | 10-bit | 10-bit | 10-bit | 10-bit | 12-bit |
| I/O Pins | 32 | 32 | 32 | 32 | 32 |
| Unit Price (qty 1) | $4.19 | Similar ($4.10-4.30) | Similar ($4.20-4.50) | Lower ($3.90-4.10) | Similar ($4.20-4.40) |
Key Differentiators
- Integrated Single-Phase Induction Motor Control Kernel (vs PIC18LF4520T-I/PT)
- Lower operating voltage (2.0V-3.3V) than the non-LF variant (vs PIC18F4539T-I/PT)
- Pin-compatible with PIC18LF4523 family for upgrade path (vs PIC18LF4523T-I/PT)
- Industrial temperature grade on the same die (vs PIC18LF4539-I/PT (extended grade))
Design Notes
Place a 100nF ceramic decoupling capacitor as close as possible to each VDD/AVDD pin (pins 11, 32, 41) and a 10uF bulk capacitor on the main supply rail. The LF variant operates from 2.0V to 3.3V; ensure the regulator has at least 100mA headroom for I/O switching transients and ADC reference stability. A separate analog ground (AVSS at pin 42) should connect back to VSS at a single point to avoid ground-loop noise coupling into the A/D converter.
Route the 40MHz crystal traces (OSC1 pin 13, OSC2 pin 14) as short and symmetric as possible with a grounded guard ring. Keep high-speed switching traces (PWM, CCP outputs on PORTC) away from analog signal traces and the AVDD/AVSS pair. The TQFP-44 10x10mm package has a center thermal pad that is electrically floating - it can be soldered to a copper pour for heat spreading but must not be tied to VDD or VSS.
When using the Single-Phase Induction Motor Control Kernel, route the zero-cross detection input and current-sense amplifier output as differential pairs to the assigned CCP/AC inputs. Add an RC low-pass filter (1kohm + 100nF) on each analog input to reject switching-noise glitches from the inverter. The internal A/D reference (VREF+/VREF-) should be bypassed with 100nF + 10uF capacitors and configured for the lowest range that still accommodates the maximum sensor output.
Do not apply 5V to the LF variant - latch-up risk above 3.6V. Do not leave MCLR floating; use the recommended 10k pull-up to VDD. When programming via ICSP, ensure PGC (pin 39) and PGD (pin 40) are not loaded with capacitance greater than 30pF or the programmer may fail to communicate. Finally, configure unused I/O as outputs driven low to minimize power consumption in sleep mode.
Estimated: with 24mA per I/O and 32 I/O lines all switching simultaneously, the worst-case VDD bounce from bond-wire inductance is around 0.4V at 20ns edge rates. Place the bulk 10uF capacitor within 5mm of the VDD pins and use a power plane (not traces) on layer 2 for the VDD/VSS distribution to limit this bounce. Keep the exposed pad of the TQFP soldered to a continuous copper pour for thermal relief.
Compliance Information
RoHS and REACH compliant per Microchip material declarations. Industrial temperature grade -40C to +85C. AEC-Q100 is not applicable because the PIC18LF4539 family is not qualified for automotive safety-critical applications - for automotive, consider the PIC18FxxKxx family.