PIC18LF45K40-I/ML - 32KB Flash XLP 8-bit MCU | Microchip | 44-QFN
MPN: PIC18LF45K40-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.18 | $3.18 |
| 10 | $2.85 | $28.50 |
| 100 | $2.45 | $245.00 |
| 500 | $2.18 | $1,090.00 |
| 1,000 | $1.92 | $1,920.00 |
PIC18LF45K40-I/ML Overview
An 8-bit microcontroller (MCU) is a small computer-on-a-chip that integrates a CPU, program memory (Flash), data memory (RAM), and a rich set of peripherals into a single IC. It belongs to the hypernym hierarchy: microcontroller -> embedded processor -> integrated circuit -> semiconductor. The PIC18 family uses an enhanced Harvard RISC architecture with a modified instruction set optimized for C code density, while the LF prefix denotes the low-voltage process and XLP (eXtreme Low Power) family adds nanoWatt XLP peripherals and idle/doze/sleep modes engineered for sub-uA standby.
Key features include 32 KB (16K x 16) Flash, 256 B EEPROM, 2 KB SRAM, 36 configurable I/O pins with interrupt-on-change, a 10-bit ADC with computation (ADC2) up to 35 channels, up to 5 CCP/ECCP modules, two UART/USART with LIN support, two SPI, two I2C (MSSP), a windowed watchdog timer (WWDT), a CRC/SCAN module, and a Complementary Waveform Generator (CWG). Core Independent Peripherals such as CWG, WWDT, and CRC/Memory Scan allow hardware-driven tasks to run without CPU intervention, lowering active duty cycle.
The PIC18LF45K40 is built on Microchip's enhanced mid-range core with a 16-bit instruction word and 8-bit data path, executing most instructions in one cycle (4 clock cycles internally). At 64 MHz the core delivers up to 16 MIPS, which is sufficient for sensor fusion, simple state machines, and protocol bridging in IoT edge nodes. Internal voltage reference and zero-cross detect simplify mains-coupled designs without external components.
Typical applications include IoT sensor nodes, battery-powered wearables, home automation controllers, industrial sensor hubs, automotive body and interior modules, low-power remote controls, and consumer appliance user interfaces. The combination of XLP sleep current below 50 nA (typical) and rapid wake-up makes it well-suited for energy-harvesting and EnergyBLINK-style designs where quiescent drain dominates battery life.
When designing with this device, observe the 3.6V absolute-maximum on VDD and avoid back-powering through I/O pins. Place a 100 nF decoupling capacitor as close as possible to each VDD/VSS pair and follow Microchip AN585 for QFN thermal via layouts under the exposed pad. The -I (Industrial) suffix denotes -40C to +85C operating range; for -40C to +125C automotive, choose the -E or -Q1 variants.
This page synthesizes distributor pricing, drop-in alternatives, comparison tables, and practical design notes not found in the manufacturer datasheet alone, helping engineers shorten evaluation cycles and avoid common PIC18LF layout pitfalls.
Drop-in alternatives for PIC18LF45K40-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 PIC18LF45K40-I/ML (same form factor and footprint) — differing in ADC, Package, Core, Operating Temperature, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F45K40-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF45K40-E/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF45K40T-I/ML
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC18LF46K40-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF45K40-E/PT
✅ Drop-In✓ In Stock
$1.86 / Unit
View Datasheet →PIC18LF45K40-E/MV
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →PIC18LF45K40-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (Enhanced Mid-Range) 8-bit |
| Program Memory (Flash) | 32 KB (16K x 16 words) |
| Data Memory (SRAM) | 2 KB |
| Data EEPROM | 256 B |
| Maximum CPU Speed | 64 MHz (16 MIPS) |
| Supply Voltage (VDD) | 1.8 V to 3.6 V |
| Operating Temperature | -40 C to +85 C (Industrial) |
| I/O Pins | 36 |
| ADC | 10-bit, up to 35 channels with ADC2 computation |
| Timers | Multiple 8/16-bit with WWDT |
| Communication | 2x UART (LIN), 2x SPI, 2x I2C (MSSP) |
| CCP/ECCP Modules | Up to 5 |
| Package | 44-pin QFN (8x8 mm) with EP |
| Mounting Type | Surface Mount |
| Low-Power Technology | nanoWatt XLP |
| RoHS Status | Compliant |
PIC18LF45K40-I/ML Pin Configuration
| Pin 1 | RA2 — PORTA digital I/O / analog input |
| Pin 2 | RA3 — PORTA digital I/O |
| Pin 3 | RA4 — PORTA digital I/O / timer clock input |
| Pin 4 | RA5 — PORTA digital I/O |
| Pin 5 | RA6 — PORTA digital I/O / oscillator output |
| Pin 6 | RA7 — PORTA digital I/O / oscillator input |
| Pin 7 | VDD — Positive supply voltage (1.8V-3.6V) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RB0 — PORTB digital I/O / interrupt-on-change |
| Pin 10 | RB1 — PORTB digital I/O / interrupt-on-change |
| Pin 11 | RB2 — PORTB digital I/O / interrupt-on-change |
| Pin 12 | RB3 — PORTB digital I/O / interrupt-on-change |
| Pin 13 | RB4 — PORTB digital I/O / interrupt-on-change |
| Pin 14 | RB5 — PORTB digital I/O / interrupt-on-change |
| Pin 15 | RB6 — PORTB digital I/O / ICSPCLK |
| Pin 16 | RB7 — PORTB digital I/O / ICSPDAT |
| Pin 17 | VSS — Ground reference |
| Pin 18 | VDD — Positive supply voltage |
| Pin 19 | RC0 — PORTC digital I/O |
| Pin 20 | RC1 — PORTC digital I/O / CCP |
| Pin 21 | RC2 — PORTC digital I/O / CCP / PWM |
| Pin 22 | RC3 — PORTC digital I/O / SCL |
| Pin 23 | RC4 — PORTC digital I/O / SDA |
| Pin 24 | RC5 — PORTC digital I/O / SDO |
| Pin 25 | RC6 — PORTC digital I/O / TX |
| Pin 26 | RC7 — PORTC digital I/O / RX |
| Pin 27 | VSS — Ground reference |
| Pin 28 | VDD — Positive supply voltage |
| Pin 29 | RE0 — PORTE digital I/O / analog input |
| Pin 30 | RE1 — PORTE digital I/O / analog input |
| Pin 31 | RE2 — PORTE digital I/O / analog input |
| Pin 32 | RE3 — PORTE digital I/O / MCLR/Reset |
| Pin 33 | RD0 — PORTD digital I/O / PSP data |
| Pin 34 | RD1 — PORTD digital I/O / PSP data |
| Pin 35 | RD2 — PORTD digital I/O / PSP data |
| Pin 36 | RD3 — PORTD digital I/O / PSP data |
| Pin 37 | RD4 — PORTD digital I/O / PSP data |
| Pin 38 | RD5 — PORTD digital I/O / PSP data |
| Pin 39 | RD6 — PORTD digital I/O / PSP data |
| Pin 40 | RD7 — PORTD digital I/O / PSP data |
| Pin 41 | VSS — Ground reference |
| Pin 42 | VOUT — Voltage regulator output (core) |
| Pin 43 | VDD — Positive supply voltage |
| Pin 44 | RA0 — PORTA digital I/O / analog input |
Typical Applications
PIC18LF45K40-I/ML is suitable for 7 applications: IoT Sensor Nodes, Battery-Powered Wearable Devices, Industrial Sensor Hubs, Automotive Body and Interior Modules, Low-Power Remote Controls, Consumer Appliance User Interfaces, Energy Harvesting Wireless Switches.
IoT Sensor Nodes
The PIC18LF45K40-I/ML is well-suited for battery-powered IoT sensor nodes thanks to its nanoWatt XLP technology, sub-50 nA typical sleep current, and 1.8 V-3.6 V wide operating range that accepts 2xAA or LiSOCl2 primary cells. The 64 MHz core with 16 MIPS handles simple sensor-fusion loops and BLE/Wi-Fi co-processor handshakes over UART or SPI. The 10-bit ADC with ADC2 computation offloads averaging, oversampling, and threshold detection in hardware so the CPU remains in sleep most of the time, extending coin-cell life to multiple years.
Recommended
Battery-Powered Wearable Devices
Wearables such as fitness bands, medical patches, and smart watches benefit from the PIC18LF45K40-I/ML's XLP sleep modes below 50 nA typical, rapid wake-up, and compact QFN-44 footprint that fits inside 20 mm coin-cell enclosures. The CWG and ECCP modules drive PWM-controlled haptic actuators, while the ADC2 with computation enables low-power heart-rate and SpO2 photodiode readout without CPU intervention. Operating down to 1.8 V lets the design continue running as the Li-ion cell drops below 3.0 V, preserving usable runtime.
Recommended
Industrial Sensor Hubs
Factory-floor sensor hubs benefit from the PIC18LF45K40-I/ML's wide 1.8-3.6 V supply, robust 10-bit ADC with up to 35 channels for multi-sensor acquisition, and LIN-compatible UART for industrial networking. The integrated CRC/Memory Scan and Windowed WDT (WWDT) module simplify functional-safety-aware diagnostics in IEC 61508-style designs, while the 36 I/O pins interface directly to 4-20 mA loops, opto-isolators, and relay drivers. Industrial -40 C to +85 C operation is guaranteed by the -I temperature grade.
Recommended
Automotive Body and Interior Modules
Body controllers, lighting nodes, and interior climate modules use the PIC18LF45K40-I/ML for its automotive-grade temperature resilience and LIN/UART transceivers. The CWG module generates complementary PWM outputs up to 50 ns resolution for LED drivers and motor pre-drivers, while 5V-tolerant I/O interfaces directly to 12 V automotive rails through external resistive dividers. The -40 C to +125 C automotive-qualified /Q1 version (PIC18LF45K40-E/ML) is recommended for under-hood deployments where the standard -I grade's +85 C limit is insufficient.
Recommended
Low-Power Remote Controls
Infrared or sub-GHz remote controls leverage the PIC18LF45K40-I/ML's sub-50 nA XLP sleep current so that a single CR2032 cell can power the unit for years of standby. The on-board 31 kHz LFINTOSC and Timer1 gate provide RTC-style wake-up intervals without external crystals, reducing BOM cost. CWG and CCP modules generate 38 kHz carrier waveforms for IR transmitters, while the USART with LIN support enables bidirectional remote communication in industrial pendant designs.
Recommended
Consumer Appliance User Interfaces
User-interface boards in washing machines, refrigerators, and air conditioners benefit from the PIC18LF45K40-I/ML's segment-LCD support via the complementary waveform generator, up to 35 ADC channels for cap-touch buttons, and robust UART/SPI/I2C peripherals for main-MCU communication. The 1.8-3.6 V supply accepts 3.3 V regulated rails common in modern appliance designs. With 32 KB Flash, manufacturers can integrate full touch-sensing libraries and customizable UI logic without external memory.
Recommended
Energy Harvesting Wireless Switches
Self-powered light switches and IoT push-buttons harvest energy from mechanical actuation and require an MCU that wakes up, transmits, and returns to sleep within microjoules of available energy. The PIC18LF45K40-I/ML's nanoWatt XLP technology offers wake-up times below 5 us from sleep and idle currents around 1.5 uA at 1.8 V, making it ideal for these constrained energy budgets. The integrated ADC monitors the harvester capacitor voltage to determine transmit timing, while the CWG generates the carrier for the radio companion.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF45K40-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F45K40-I/ML | PIC18LF45K40-E/ML | PIC18LF46K40-I/ML |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-QFN (8x8 mm) | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Flash Memory | 32 KB | 32 KB | 32 KB | 64 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 4 KB |
| Operating Voltage | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| CPU Speed | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C |
| I/O Pins | 36 | 36 | 36 | 36 |
| 1k Price (USD) | 1.92 | 1.92 (similar) | 2.05 | 2.20 |
Key Differentiators
- Lowest-voltage operation in family at 1.8 V minimum (vs PIC18F45K40-I/ML)
- Higher Flash density than the K22 family (vs PIC18LF45K22-I/ML)
- Same package as 64 KB sibling, enables memory scaling on same PCB (vs PIC18LF46K40-I/ML)
- Extended-temperature option in same footprint (vs PIC18LF45K40-E/ML)
Design Notes
The QFN-44 package exposes a thermal pad (EP) that must be soldered to a copper land on the PCB for both electrical ground and heat dissipation. The exposed pad reduces junction-to-ambient thermal resistance (theta_JA) by approximately 40% versus an unbonded QFN, so designers should follow Microchip AN585 (QFN Land Pattern and Thermal Management) when laying out the footprint. Use thermal vias (8-12 vias, 0.3 mm drill, 1.0 mm pitch) directly under the EP to the internal ground plane, and avoid signal traces crossing the EP area.
Place a 100 nF X7R ceramic decoupling capacitor as close as possible to each VDD/VSS pair (pins 7/8, 17/18, 27/28, 41/43) within 3 mm trace length. Add a single bulk 1 uF to 10 uF tantalum or ceramic bypass on the main VDD rail. The PIC18LF45K40-I/ML's nanoWatt XLP sleep current is below 50 nA typical only when all peripherals are disabled and the BOR is configured for low-power mode; consult the PIC18F45K40 datasheet section on power-saving modes for Sleep, Idle, and Doze configurations.
Avoid routing analog ADC signals (RA0-RA7, RE0-RE2) parallel to high-speed digital lines (SPI, PWM outputs) on adjacent layers to prevent coupling noise into ADC readings. Place a ground guard ring around sensitive analog traces and use a star-ground topology that ties the analog and digital grounds at a single point near the MCU's VSS pin. For 10-bit ADC accuracy at 3.3 V, ensure the reference voltage source impedance stays below 3 kOhm as recommended in Microchip AN1079.
Do not apply voltage to any I/O pin before VDD is present, as the PIC18LF45K40 can back-power through I/O clamping diodes and enter undefined states. Always tie the MCLR pin (RE3) high through a 10 kOhm pull-up to VDD, and place a 100 nF cap on MCLR to ground for noise immunity. The LF variant supports 1.8 V minimum VDD; programming the device below 2.0 V may fail during ICSP, so ensure VDD is at least 2.0 V during in-circuit programming.
When using the MSSP peripheral for I2C at 400 kHz or higher, place 2.2 kOhm to 10 kOhm pull-up resistors on SDA and SCL lines, and keep total bus capacitance below 400 pF. For SPI at 8 MHz or above, use controlled-impedance traces (typically 50 ohm) and series 33 ohm damping resistors near the source to reduce ringing. Avoid stubs by routing SPI as a single daisy chain rather than a star topology.
Compliance Information
RoHS compliant per Microchip product page. Industrial -40C to +85C grade (suffix -I). For automotive AEC-Q100 qualified parts, choose the PIC18LF45K40-E/ML (extended temperature) or PIC18F45K40-E/ML.
