PIC18LF45K42T-I/ML - 64MHz 8-bit MCU 32KB 44-QFN | Microchip
MPN: PIC18LF45K42T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.5 | $3.50 |
| 10 | $3.15 | $31.50 |
| 100 | $2.78 | $278.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.18 | $2,180.00 |
| 1,600 | $1.98 | $3,168.00 |
PIC18LF45K42T-I/ML Overview
An 8-bit microcontroller (MCU) is a programmable computing IC that integrates CPU, non-volatile program memory, RAM, and a peripheral set onto a single die. It occupies the middle of the embedded hierarchy: transistor -> logic gate -> microprocessor -> microcontroller -> embedded system. The "LF" prefix indicates the low-voltage core designed for battery-friendly XLP (eXtreme Low Power) operation, suitable for always-on IoT and portable products.
Key features include a 12-bit ADC2 with computation, a 5-bit DAC, two comparators, multiple PWM channels, vector interrupts, DMA, MAP (Memory Access Partitioning), a Device Information Area (DIA), and Core Independent Peripherals. The 36 I/O pins provide flexibility for mixed-signal designs.
Architecturally, the device uses Microchip's enhanced PIC18 RISC core with a modified Harvard bus and 16-bit wide instructions fetched from Flash while data is moved over an 8-bit path. Independent peripheral clocks allow the CPU to sleep while peripherals continue to service events, supporting deep XLP sleep currents in the nanoamp range for battery applications.
Typical uses include low-power IoT sensor nodes, battery-powered wearables, consumer appliances, motor and lighting control, USB-CDC/HID bridges, and industrial sensor interfaces. The combination of DMA and 12-bit ADC2 with computation enables deterministic signal acquisition without CPU intervention.
When designing in, route the exposed pad (EP) to a solid ground copper pour to manage thermal dissipation and provide low-impedance return. Configure the PPS (Peripheral Pin Select) pins via the configuration registers during firmware bring-up to remap peripherals without PCB rework.
This page synthesizes authorized distributor pricing, drop-in compatible alternatives, and practical design notes not aggregated in any single manufacturer document.
Drop-in alternatives for PIC18LF45K42T-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 PIC18LF45K42T-I/ML (same form factor and footprint) — differing in ADC, Package, Operating Temperature, I/O Pins, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF45K42-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF45K42-E/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF46K42-I/ML
✅ Drop-In✓ In Stock
$1.83 / Unit
View Datasheet →PIC18LF45K40T-I/ML
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC18LF45K40-I/ML
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18LF45K42T-I/ML Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| Program Memory | 32 KB Flash |
| Data RAM | 2 KB |
| EEPROM | 256 B |
| Maximum CPU Frequency | 64 MHz |
| Operating Voltage | 1.8 V to 3.6 V |
| Operating Temperature | -40 C to +85 C (Industrial, "I") |
| I/O Pins | 36 |
| ADC | 12-bit ADC2 with computation |
| DAC | 5-bit DAC |
| Comparators | 2 |
| PWM Channels | Multiple (per datasheet) |
| DMA | Yes |
| Vector Interrupts | Yes |
| Peripheral Features | MAP, DIA, Core Independent Peripherals |
| Package | 44-QFN (8x8 mm) with exposed pad, /ML |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| MSL Level | 3 (per JEDEC J-STD-020) |
| Series | PIC18F45K42 (LF low-voltage, K42 family) |
PIC18LF45K42T-I/ML Pin Configuration
| Pin 1 | RA0 — PORTA bit 0 / analog / digital I/O |
| Pin 2 | RA1 — PORTA bit 1 / analog / digital I/O |
| Pin 3 | RA2 — PORTA bit 2 / analog / digital I/O |
| Pin 4 | RA3 — PORTA bit 3 / analog / digital I/O |
| Pin 5 | RA4 — PORTA bit 4 / analog / digital I/O |
| Pin 6 | RA5 — PORTA bit 5 / analog / digital I/O |
| Pin 7 | RA6 — PORTA bit 6 / analog / digital I/O |
| Pin 8 | RA7 — PORTA bit 7 / analog / digital I/O |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Positive supply input |
| Pin 11 | RB0 — PORTB bit 0 / analog / digital I/O |
| Pin 12 | RB1 — PORTB bit 1 / analog / digital I/O |
| Pin 13 | RB2 — PORTB bit 2 / analog / digital I/O |
| Pin 14 | RB3 — PORTB bit 3 / analog / digital I/O |
| Pin 15 | RB4 — PORTB bit 4 / analog / digital I/O |
| Pin 16 | RB5 — PORTB bit 5 / analog / digital I/O |
| Pin 17 | RB6 — PORTB bit 6 / analog / digital I/O |
| Pin 18 | RB7 — PORTB bit 7 / analog / digital I/O |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply input |
| Pin 21 | RC0 — PORTC bit 0 / analog / digital I/O |
| Pin 22 | RC1 — PORTC bit 1 / analog / digital I/O |
| Pin 23 | RC2 — PORTC bit 2 / analog / digital I/O |
| Pin 24 | RC3 — PORTC bit 3 / analog / digital I/O |
| Pin 25 | RC4 — PORTC bit 4 / analog / digital I/O |
| Pin 26 | RC5 — PORTC bit 5 / analog / digital I/O |
| Pin 27 | RC6 — PORTC bit 6 / analog / digital I/O |
| Pin 28 | RC7 — PORTC bit 7 / analog / digital I/O |
| Pin 29 | VSS — Ground reference |
| Pin 30 | VDD — Positive supply input |
| Pin 31 | RD0 — PORTD bit 0 / analog / digital I/O |
| Pin 32 | RD1 — PORTD bit 1 / analog / digital I/O |
| Pin 33 | RD2 — PORTD bit 2 / analog / digital I/O |
| Pin 34 | RD3 — PORTD bit 3 / analog / digital I/O |
| Pin 35 | RD4 — PORTD bit 4 / analog / digital I/O |
| Pin 36 | RD5 — PORTD bit 5 / analog / digital I/O |
| Pin 37 | RD6 — PORTD bit 6 / analog / digital I/O |
| Pin 38 | RD7 — PORTD bit 7 / analog / digital I/O |
| Pin 39 | VSS — Ground reference |
| Pin 40 | VDD — Positive supply input |
| Pin 41 | RE0 — PORTE bit 0 / analog / digital I/O |
| Pin 42 | RE1 — PORTE bit 1 / analog / digital I/O |
| Pin 43 | RE2 — PORTE bit 2 / analog / digital I/O |
| Pin 44 | RE3 — PORTE bit 3 / analog / digital I/O |
Typical Applications
PIC18LF45K42T-I/ML is suitable for 7 applications: Battery-Powered IoT Sensor Node, Consumer Appliance Control Board, Motor and Fan Speed Control, Industrial Sensor Interface Module, USB Human Interface Device (HID), Portable Medical Wearable, Smart Home Lighting Controller.
Battery-Powered IoT Sensor Node
The PIC18LF45K42T-I/ML is well matched to battery-powered IoT sensor nodes because of its 1.8V-3.6V LF core, deep XLP sleep modes in the nanoamp range, and 12-bit ADC2 with computation that wakes the CPU only on threshold crossings. Operating at 64MHz, it can sample sensors, run DSP-style averaging, and transmit results in short bursts before returning to sleep. With 32KB Flash, designers fit BLE/Zigbee stack stubs plus application code; with 256B EEPROM, they store calibration and network credentials without external memory. Compared with a 5V PIC18F part, the LF core drains a single-cell Li-ion or 2xAA pack for months longer.
Recommended
Consumer Appliance Control Board
In white-goods and small consumer appliances the PIC18LF45K42T-I/ML serves as a single-chip controller that drives TRIACs, reads keypads, and manages user interfaces. The 36 I/O pins multiplex with PWM, comparator wake-on-touch, and the 12-bit ADC2 to monitor temperature, current, and voltage. Its PPS feature lets designers re-route peripherals between board revisions without changing the PCB. The 44-QFN with exposed pad handles thermal dissipation when driving relays directly, while the 1.8V-3.6V supply accepts a regulated 3.3V rail shared with the wireless module.
Recommended
Motor and Fan Speed Control
The PIC18LF45K42T-I/ML is well suited to BLDC and brushed DC motor control because its 12-bit ADC2 samples back-EMF and current precisely while Core Independent Peripherals drive PWMs without CPU load. The two comparators can trigger zero-cross detection for synchronous rectification, and DMA offloads repetitive control loops. The vector interrupt controller keeps response time under deterministic bounds, critical for sensorless trapezoidal commutation. Its 64MHz instruction rate is more than adequate for 20kHz PWM loops while leaving headroom for UART diagnostics.
Recommended
Industrial Sensor Interface Module
For industrial 4-20mA loop and Modbus sensor modules, the PIC18LF45K42T-I/ML combines an RS-485-capable UART, ADC2 for analog front-end, and 32KB Flash for Modbus stack and calibration tables. The DIA stores factory trim and unique ID, while MAP enables bootloader-protected firmware updates in the field. The exposed pad on the 44-QFN package bonds to the chassis ground, providing EMI resilience on noisy factory floors. Operating temperature -40C to +85C suits most industrial enclosures without derating.
Recommended
USB Human Interface Device (HID)
With DMA, vector interrupts, and 64MHz performance, the PIC18LF45K42T-I/ML can serve as a USB HID device (keyboard, mouse, custom interface) over the Microchip USB stack running on the K42 family. The 36 I/O pins scan key matrices while the CPU handles USB housekeeping, and PPS routes the USB D+/D- signals. EEPROM stores user preferences such as backlight and keymap. The 32KB Flash comfortably holds the USB stack plus application firmware for low-cost consumer peripherals.
Recommended
Portable Medical Wearable
Medical wearables such as pulse oximeters, continuous glucose monitors, and smart patches benefit from the PIC18LF45K42T-I/ML's XLP deep sleep currents and 12-bit ADC2 with computation for photoplethysmography (PPG) front-ends. The DMA transfers ADC samples into RAM without waking the CPU, enabling multi-hour battery life. The MAP feature enforces a bootloader boundary for safe firmware updates. The 44-QFN package fits inside small enclosures, and the exposed pad supports a thermal path when paired with a skin-contact sensor.
Recommended
Smart Home Lighting Controller
In connected LED lighting controllers, the PIC18LF45K42T-I/ML provides PWM channels for dimming, ADC2 for ambient-light and color sensing, and DMA-managed UART for wireless co-processor handshaking. The 1.8V-3.6V supply accepts power harvested from AC-to-DC converter front-ends, while XLP sleep preserves standby energy when lights are off. The exposed pad dissipates heat from PWM-driven MOSFETs placed near the MCU. The 32KB Flash supports Zigbee or BLE-Mesh network stacks plus custom lighting logic.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF45K42T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF45K42-I/ML | PIC18LF45K42-E/ML | PIC18LF46K42-I/ML | PIC18LF45K40T-I/ML | PIC18LF45K40-I/ML |
|---|---|---|---|---|---|---|
| Package | 44-QFN (8x8 mm) /ML | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash | 32 KB | 32 KB | 32 KB | 64 KB (+100%) | 32 KB | 32 KB |
| RAM | 2 KB | 2 KB | 2 KB | 4 KB (+100%) | 2 KB | 2 KB |
| Maximum Frequency | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| Operating Voltage | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| ADC | 12-bit ADC2 | 12-bit ADC2 | 12-bit ADC2 | 12-bit ADC2 | 10-bit ADC (older core) | 10-bit ADC (older core) |
| Operating Temperature | -40 C to +85 C (I) | -40 C to +85 C (I) | -40 C to +125 C (E, extended) | -40 C to +85 C (I) | -40 C to +85 C (I) | -40 C to +85 C (I) |
| DMA | Yes | Yes | Yes | Yes | No | No |
| Tier 1 Price (USD) | 3.50 | 3.60 (slightly higher tray-only) | 3.85 (extended temperature premium) | 4.20 (64KB Flash uplift) | 3.20 (older core discount) | 3.30 (older core) |
Key Differentiators
- Same QFN package as K40 with K42 features (vs PIC18LF45K40T-I/ML)
- Higher memory density within the same footprint (vs PIC18LF45K22T-I/MV)
- Drop-in extended-temperature variant available (vs PIC18LF45K42-E/ML)
Design Notes
Solder the exposed thermal pad (EP) of the 44-QFN package to a continuous ground copper pour. Estimated: with 1 square inch of 2 oz copper on each layer stitched with thermal vias, theta_JA drops from approximately 30 C/W (no EP solder) to under 20 C/W. Without the EP soldered, the MCU will overheat in PWM-driven motor designs above ~300mA load. Use at least 9 thermal vias (0.3mm drill) connecting the top EP pad to inner ground planes.
Decouple VDD/VSS pairs with a 100nF ceramic placed within 5mm of each VDD pin. Estimated: with three VDD/VSS pairs on the 44-QFN, place three 100nF X7R caps plus one bulk 10uF ceramic. The ADC2 is sensitive to VDD ripple; use a ferrite bead plus RC filter (10 ohm + 100nF) on the analog AVdd rail to achieve 12-bit stable readings without averaging.
Do not confuse PIC18LF45K42 (1.8V-3.6V) with PIC18F45K42 (2.3V-5.5V). The LF core browns out above 3.6V; the F core will not start below 2.3V. Mismarking during PCB bring-up is a common field return source. Verify the top-marking per the Microchip ordering information before powering a new PCB. Configuration bits must be set correctly or the MCU may execute from a wrong oscillator source.
Route PPS-mapped signals to short PCB traces and avoid running them parallel to PWM or switching nodes for more than 10mm. The PPS feature allows peripheral remapping, but trace lengths and impedance are not accounted for in PPS configuration. For USB, keep D+/D- traces 90 ohms differential and match lengths to within 2mm.
Compliance Information
RoHS and REACH compliance per Microchip product page; not AEC-Q100 qualified - the automotive grade would be the PIC18F45K42-E/ML or PIC18F46K42-E/ML variants. Lead-free reflow per JEDEC J-STD-020 MSL3.
