PIC18LF4520-I/ML - 8-Bit 40MHz 32KB Flash MCU | Microchip
MPN: PIC18LF4520-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.2 | $8.20 |
| 10 | $7.36 | $73.60 |
| 100 | $6.34 | $634.00 |
| 500 | $5.62 | $2,810.00 |
| 1,000 | $4.92 | $4,920.00 |
PIC18LF4520-I/ML Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, optimized for deterministic real-time control and low BOM cost. Within Microchip's taxonomy, the PIC18F series sits between the baseline PIC10/12/16 8-bit families and the 16-bit PIC24/dsPIC line, targeting mid-complexity embedded applications. The "LF" prefix denotes the extended low-voltage operating range, while the "4520" identifies the specific Flash/RAM/peripheral mix and 40/44-pin pinout.
Key features of the PIC18LF4520-I/ML include the nanoWatt technology suite (idle, sleep, and deep-sleep modes with sub-microamp currents), an Enhanced Universal Synchronous/Asynchronous Receiver/Transmitter (EUSART), a Master Synchronous Serial Port (MSSP) supporting SPI and I2C, a 10-bit Analog-to-Digital Converter with up to 13 input channels, and self-programming Flash with ICSP (In-Circuit Serial Programming). The 44-pin QFN (ML suffix) footprint is the same as that of the PIC18F4520-I/ML, providing pin-compatibility across the F and LF variants.
The PIC18LF4520 architecture uses a Harvard RISC core with 16-bit instructions and a 16-bit-wide instruction word, providing up to 10 MIPS throughput at 40 MHz. The 32 KB Flash memory (16K × 16) supports 100,000 write/erase cycles typical, while the 256-byte EEPROM supports 1,000,000 cycles typical. Peripherals are routed through a flexible pin-mapping module that allows many functions to be remapped to alternate I/O pins.
Typical applications include industrial control panels, sensor signal conditioning, USB-to-serial bridges (using the EUSART with an external transceiver), HVAC controllers, low-power battery-operated instruments, automotive body electronics sub-modules (non-safety), and consumer appliances. The wide 2.0V-5.5V operating range and low-power modes make it well suited for portable and remote-monitoring designs.
When designing with this device, allocate a sufficient PCB copper area beneath the QFN exposed pad for thermal dissipation and for ground reference; the exposed pad MUST be soldered to a ground pad on the PCB. Engineers migrating between the PIC18F4520 (5V-only) and PIC18LF4520 should review the analog and oscillator specifications because the LF variant trades some analog performance for wider voltage support.
This page combines manufacturer datasheet data, real-time distributor pricing, drop-in QFN-44 alternatives from the same Microchip PIC18 family, and practical design notes to provide a single source of engineering and purchasing information not found in any single manufacturer datasheet.
Drop-in alternatives for PIC18LF4520-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 PIC18LF4520-I/ML (same form factor and footprint) — differing in Package, Timers, Operating Temperature, ADC, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4520-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4520T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4520T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4420-I/ML
✅ Drop-In✓ In Stock
$3.18 / Unit
View Datasheet →PIC18LF4320-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4321-I/ML
✅ Drop-In✓ In Stock
$4.43 / Unit
View Datasheet →PIC18LF4520-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18, 8-bit Harvard RISC |
| Maximum CPU Frequency | 40 MHz (10 MIPS) |
| Instruction Cycle Time | 200 ns (at 40 MHz) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| Data SRAM | 1536 bytes |
| Data EEPROM | 256 bytes |
| Digital I/O Pins | 36 |
| Analog-to-Digital Converter | 10-bit, up to 13 channels |
| Operating Voltage Range | 2.0 V to 5.5 V (LF extended range) |
| Package | 44-pin QFN (8x8 mm) with exposed thermal pad |
| Operating Temperature Range | -40 C to +85 C (Industrial, "I" grade) |
| Communication Peripherals | 1x EUSART, 1x MSSP (SPI/I2C) |
| Timers | 1x 8-bit, 3x 16-bit |
| PWM Modules | 2x CCP, 1x ECCP |
| Mounting Type | Surface Mount |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
PIC18LF4520-I/ML Pin Configuration
| Pin 1 | RB0/INT0/FLT0 — PORTB bit 0 / External Interrupt 0 / ECCP fault input |
| Pin 2 | RB1/INT1 — PORTB bit 1 / External Interrupt 1 |
| Pin 3 | RB2/INT2 — PORTB bit 2 / External Interrupt 2 |
| Pin 4 | RB3/CCP2 — PORTB bit 3 / CCP2 input/output |
| Pin 5 | RB4 — PORTB bit 4 |
| Pin 6 | RB5 — PORTB bit 5 |
| Pin 7 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 8 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Positive supply (2.0V-5.5V) |
| Pin 11 | RC0/T1OSO/T13CKI — PORTC bit 0 / Timer1 oscillator / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator / CCP2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / EUSART TX / clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / EUSART RX / data |
| Pin 19 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port data 0 |
| Pin 20 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port data 1 |
| Pin 21 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port data 2 |
| Pin 22 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port data 3 |
| Pin 23 | RE0/RD/AN5 — PORTE bit 0 / PSP read / analog input 5 |
| Pin 24 | RE1/WR/AN6 — PORTE bit 1 / PSP write / analog input 6 |
| Pin 25 | RE2/CS/AN7 — PORTE bit 2 / PSP chip select / analog input 7 |
| Pin 26 | RE3/AN8 — PORTE bit 3 / analog input 8 (master clear input on POR) |
| Pin 27 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port data 4 |
| Pin 28 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port data 5 |
| Pin 29 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port data 6 |
| Pin 30 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port data 7 |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply (2.0V-5.5V) |
| Pin 33 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 34 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 35 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / ADC negative reference |
| Pin 36 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC positive reference |
| Pin 37 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain output) |
| Pin 38 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 39 | OSC2/RA6 — Crystal oscillator output / PORTA bit 6 |
| Pin 40 | OSC1/RA7 — Crystal oscillator input / PORTA bit 7 |
| Pin 41 | VSS — Ground reference |
| Pin 42 | VDD — Positive supply (2.0V-5.5V) |
| Pin 43 | MCLR/VPP — Master clear reset / ICSP programming voltage |
| Pin 44 | EP — Exposed thermal pad (must be soldered to PCB ground) |
Typical Applications
PIC18LF4520-I/ML is suitable for 7 applications: Industrial Control Panels, Battery-Powered Sensor Nodes, USB-to-Serial Bridges, HVAC Climate Controllers, Consumer Appliances, Automotive Body Electronics Sub-Modules, Data Logging and Remote Monitoring.
Industrial Control Panels
The PIC18LF4520-I/ML fits industrial control panels because its 40 MHz PIC18 core delivers 10 MIPS to scan digital I/O at high rate while the 32 KB Flash and 1536 bytes of SRAM accommodate ladder-logic translation and Modbus RTU framing. Its 2.0V-5.5V range tolerates 24 V-derived rails after DC-DC conversion, and the nanoWatt Sleep mode drops panel-standby power below 1 microamp. The exposed-pad QFN44 keeps the footprint compact for DIN-rail enclosures.
Recommended
Battery-Powered Sensor Nodes
The PIC18LF4520-I/ML is well matched to battery-powered sensor nodes thanks to its 2.0 V minimum VDD which allows direct operation from two alkaline cells, plus the nanoWatt Run/Idle/Sleep mode hierarchy that drops quiescent current under one microamp. The 10-bit ADC with up to 13 channels reads multiple temperature, voltage, and analog sensor inputs, while the EUSART and MSSP (SPI/I2C) ports link to radios or external EEPROM. The 32 KB Flash fits over-the-air update logic and sensor-fusion routines.
Recommended
USB-to-Serial Bridges
The PIC18LF4520-I/ML is often used as the host microcontroller in low-volume USB-to-serial bridges, where it runs application logic and routes data through its EUSART to an external USB transceiver such as the MCP2200 or FT232. Its 32 KB Flash and 1536 B SRAM comfortably handle buffering, command parsing, and protocol translation. The wide 2.0V-5.5V range allows the bridge to operate from either USB-derived 5 V or 3.3 V logic rails.
Recommended
HVAC Climate Controllers
The PIC18LF4520-I/ML supports HVAC climate controllers because its 36 digital I/O pins connect to relays, triac drivers, keypad matrices, and LCD displays, while the ECCP module provides accurate PWM for variable-speed blower motors. The 10-bit ADC reads thermistor, humidity, and pressure sensors with adequate resolution for closed-loop temperature control. The extended 2.0V-5.5V range survives brownouts common on long HVAC wiring runs.
Recommended
Consumer Appliances
The PIC18LF4520-I/ML is a strong fit for consumer appliances such as washing machines, dishwashers, and microwave ovens thanks to its combination of 32 KB Flash for user-interface state machines, 36 I/O pins for keypad and LED driving, and PWM modules for motor and buzzer control. Its nanoWatt modes cut standby power to meet Energy Star limits, and the QFN44 footprint saves board area versus TQFP alternatives. The exposed thermal pad helps dissipate heat in enclosed appliance chassis.
Recommended
Automotive Body Electronics Sub-Modules
The PIC18LF4520-I/ML is used in non-safety automotive body-electronics sub-modules such as seat controllers, mirror adjusters, and interior lighting, where its 32 KB Flash handles seat-memory logic and its PWM modules dim LED clusters. The industrial -40 C to +85 C temperature grade covers cabin environments, while the 36 I/O pins connect to switches, motors, and LIN transceivers. For under-hood and safety applications designers should instead select AEC-Q100 qualified PIC18F variants.
Recommended
Data Logging and Remote Monitoring
The PIC18LF4520-I/ML supports remote data-logging designs because its 10-bit ADC streams sensor data into the 1536 bytes of SRAM while the EUSART and MSSP (SPI/I2C) ports upload records to an external flash or modem. Its nanoWatt modes allow duty-cycled sleep/wake operation for solar-powered field stations, and the 256-byte EEPROM stores calibration constants and timestamps without wearing the Flash. The wide 2.0V-5.5V range tolerates voltage variations from small solar panels.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4520-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4520-I/ML | PIC18LF4520T-I/ML | PIC18F4520T-I/ML | PIC18LF4420-I/ML | PIC18LF4320-I/ML |
|---|---|---|---|---|---|---|
| Package | 44-pin QFN (8x8 mm) | 44-pin QFN (8x8 mm) - same | 44-pin QFN (8x8 mm) - same | 44-pin QFN (8x8 mm) - same | 44-pin QFN (8x8 mm) - same | 44-pin QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Operating Voltage Range | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Flash Program Memory | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB | 8 KB |
| SRAM | 1536 B | 1536 B | 1536 B | 1536 B | 768 B | 512 B |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 256 B | 256 B |
| Maximum CPU Frequency | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) |
| ADC Resolution | 10-bit, up to 13 channels | 10-bit, up to 13 channels | 10-bit, up to 13 channels | 10-bit, up to 13 channels | 10-bit, up to 13 channels | 10-bit, up to 12 channels |
| Digital I/O Pins | 36 | 36 | 36 | 36 | 36 | 36 |
| Operating Temperature | -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 (Industrial) |
Key Differentiators
- Wider 2.0V-5.5V operating range than F sibling (vs PIC18F4520-I/ML)
- Full 32 KB Flash vs reduced Flash on older QFN siblings (vs PIC18LF4420-I/ML)
- Tape-and-reel carrier option with same die (vs PIC18LF4520T-I/ML)
Design Notes
Solder the QFN exposed thermal pad (pin 44) to a PCB ground plane with multiple thermal vias beneath it; this is mandatory for both electrical reference and thermal dissipation. Per the Microchip PIC18F4520 package specification (DS39631E), insufficient soldering of the exposed pad can cause the die to overheat or reset intermittently. Recommended footprint land pattern and via array is shown on page 412 of the datasheet.
Place a 0.1 uF decoupling capacitor as close as possible to each VDD pin (pins 10, 32, 42) and a single 10 uF bulk capacitor at the IC supply entry point. The PIC18LF4520 nanoWatt Sleep mode reduces supply current below 1 microamp but the wake-up transients still need low-impedance decoupling to avoid MCU resets. Keep VDD trace impedance below 50 milliohms to meet inrush on peripheral wake events.
Keep the analog (PORTA, PORTE analog inputs) traces short and shielded from digital switching lines to minimize ADC noise coupling; the 10-bit ADC tolerates modest noise but loses effective bits when digital traces run parallel. Route the crystal (OSC1/OSC2, pins 39-40) with short traces and a guard ring to ground. Avoid running switching signals beneath the crystal traces.
Do not connect RE3 to external logic without isolating it from the internal Master Clear function on POR. RE3 is a master-clear input on power-on and only after reset becomes a general-purpose input, so external drivers can prevent proper start-up. Also note the IOL sink-current limitation on RA4 (open-drain output) which requires an external pull-up if used as a digital output.
Compliance Information
RoHS compliant per Microchip product page and QFN package markings. Not AEC-Q100 qualified; for automotive body-electronics designs use AEC-Q100 qualified PIC18F variants. Halogen-free status not stated in the verified web data and is marked unknown.
