PIC18LF55K42T-I/PT - 32KB Flash 64MHz 8-bit XLP MCU | Microchip
MPN: PIC18LF55K42T-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.62 | $4.62 |
| 10 | $4.15 | $41.50 |
| 100 | $3.68 | $368.00 |
| 500 | $3.25 | $1,625.00 |
| 1,000 | $2.84 | $2,840.00 |
| 2,500 | $2.55 | $6,375.00 |
PIC18LF55K42T-I/PT Overview
An 8-bit microcontroller (MCU) is a programmable integrated circuit that executes instructions on an 8-bit data bus, typically based on CISC (PIC, 8051) or RISC (AVR, PIC18) architectures. MCUs integrate CPU, RAM, non-volatile memory, and peripherals on a single die, forming the lowest tier of embedded computing - between discrete logic and full application processors - and serve as the decision-making core in virtually every electronic product from appliances to industrial controllers.
Key features include the eXtreme Low Power (XLP) technology for battery-friendly operation, an active clock scaling from 1 MHz to 64 MHz, four 16-bit timers, multiple UART/SPI/I2C interfaces, and a 1.8 V to 3.6 V supply range suited to single-cell Li-ion and coin-cell applications. The 48-pin TQFP-EP exposed-pad package delivers 44 usable I/O lines while providing a thermal dissipation path for the 64 MHz core.
Architecturally, the PIC18LF55K42T uses a Harvard-style RISC core with a modified instruction set supporting hardware multiply and a 16-bit instruction word, allowing most instructions to execute in one cycle. The CIP (Core Independent Peripherals) ecosystem - including CWG, NCO, DSM, and PWM - lets timing-sensitive tasks run without CPU intervention, freeing the 8-bit core for application logic.
Typical applications include IoT sensor nodes, low-power consumer devices, industrial control panels, home appliances, USB human-interface devices (when paired with the internal USB module in sister parts), motor control, and battery-backed instrumentation. The exposed-pad TQFP supports reflow profiles up to JEDEC J-STD-020 standards.
When designing with this device, choose between the internal 16 MHz HFINTOSC and an external crystal based on USB or CAN timing requirements. Note that the LF (low-voltage/F-version) variant supports 1.8 V minimum Vdd; the F-version PIC18F55K42 is required for 5 V designs, while the LF is optimal for 3.3 V regulated rails.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC18LF55K42T-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 PIC18LF55K42T-I/PT (same form factor and footprint) — differing in DAC, Package, ADC, MSL Level, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF55K42-I/PT
✅ Drop-In✓ In Stock
$2.27 / Unit
View Datasheet →PIC18LF55K42T-I/MV
✅ Drop-In✓ In Stock
$2.6 / Unit
View Datasheet →PIC18F55K42T-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF55K42-E/PT
✅ Drop-In✓ In Stock
$2.1 / Unit
View Datasheet →PIC18LF47K42-I/MV
✅ Drop-In✓ In Stock
$2.75 / Unit
View Datasheet →PIC18LF45K42T-I/PT
✅ Drop-In✓ In Stock
$2.84 / Unit
View Datasheet →PIC18LF55K42T-I/PT Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit RISC |
| Series | PIC XLP 18K |
| CPU Clock Speed | 64 MHz |
| Program Memory (Flash) | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 256 bytes |
| Operating Voltage (Vdd) | 1.8 V to 3.6 V |
| I/O Pins | 44 |
| ADC | 12-bit ADC2 with computation |
| DAC | Yes (5-bit / 8-bit modules) |
| Comparators | Yes |
| PWM Channels | Yes (multiple CCP/ECCP) |
| DMA | Yes |
| Timers | Multiple 16-bit timers |
| Communication | UART, SPI, I2C |
| Vector Interrupts | Yes |
| Memory Access Partition (MAP) | Yes |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 48-pin TQFP-EP (7x7 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 3 |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| AEC-Q100 | Not applicable (industrial grade) |
PIC18LF55K42T-I/PT Pin Configuration
| Pin 1 | RE3/MCLR — Input-only pin / Master Clear (reset) |
| Pin 2 | RA0 — GPIO / analog input |
| Pin 3 | RA1 — GPIO / analog input |
| Pin 4 | RA2 — GPIO / analog input |
| Pin 5 | RA3 — GPIO / analog input |
| Pin 6 | RA4 — GPIO |
| Pin 7 | RA5 — GPIO |
| Pin 8 | RA6 — GPIO |
| Pin 9 | RA7 — GPIO |
| Pin 10 | Vss — Ground |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | RB0 — GPIO / programming clock (PGC) |
| Pin 13 | RB1 — GPIO / programming data (PGD) |
| Pin 14 | RB2 — GPIO |
| Pin 15 | RB3 — GPIO |
| Pin 16 | RB4 — GPIO |
| Pin 17 | RB5 — GPIO |
| Pin 18 | RB6 — GPIO / ICD PGC |
| Pin 19 | RB7 — GPIO / ICD PGD |
| Pin 20 | Vss — Ground |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | RC0 — GPIO |
| Pin 23 | RC1 — GPIO |
| Pin 24 | RC2 — GPIO |
| Pin 25 | RC3 — GPIO / SCL |
| Pin 26 | RC4 — GPIO / SDA |
| Pin 27 | RC5 — GPIO |
| Pin 28 | RC6 — GPIO / TX |
| Pin 29 | RC7 — GPIO / RX |
| Pin 30 | Vss — Ground |
| Pin 31 | VDD — Positive supply voltage |
| Pin 32 | RD0 — GPIO |
| Pin 33 | RD1 — GPIO |
| Pin 34 | RD2 — GPIO |
| Pin 35 | RD3 — GPIO |
| Pin 36 | RD4 — GPIO |
| Pin 37 | RD5 — GPIO |
| Pin 38 | RD6 — GPIO |
| Pin 39 | RD7 — GPIO |
| Pin 40 | Vss — Ground |
| Pin 41 | VDD — Positive supply voltage |
| Pin 42 | RE0 — GPIO |
| Pin 43 | RE1 — GPIO |
| Pin 44 | RE2 — GPIO |
| Pin 45 | OSC1 — Crystal oscillator input |
| Pin 46 | OSC2 — Crystal oscillator output |
| Pin 47 | Vss — Ground |
| Pin 48 | VDD — Positive supply voltage |
Typical Applications
PIC18LF55K42T-I/PT is suitable for 7 applications: IoT Sensor Node / Wireless Edge Device, Industrial Control Panel / HMI, Home Appliance Control Board, Battery-Powered Medical Device, Automotive Body Electronics (Non-Safety), USB Human Interface Device (HID), Motor Control / Fan Drive.
IoT Sensor Node / Wireless Edge Device
The PIC18LF55K42T-I/PT is well-suited for IoT sensor nodes and wireless edge devices because its eXtreme Low Power (XLP) technology delivers sub-uA sleep currents and 1.8 V minimum Vdd, enabling multi-year coin-cell battery life. The 64 MHz PIC18 RISC core processes sensor fusion and wireless stack management with DMA offloading memory-to-peripheral transfers, freeing CPU cycles for application logic. Its 12-bit ADC2 with computation provides oversampling and automated threshold detection directly in hardware, reducing firmware overhead for battery voltage monitoring and analog sensor readout. The 44 I/O pins support multiple SPI/I2C sensors, GPIO expanders, and status LEDs. Placed on a 3.0 V CR2032 or single-cell Li-ion rail with a sub-GHz transceiver companion, it forms a wireless sensor node that meets BLE/Zigbee duty-cycling requirements.
Recommended
Industrial Control Panel / HMI
For industrial control panels and HMI terminals, the PIC18LF55K42T-I/PT's 32 KB Flash and 2 KB RAM provide ample space for menu navigation, button debouncing, and status display logic. The 64 MHz CPU supports real-time keypad scanning and LCD/character-display updates without visible latency. The 12-bit ADC2 with computation reads analog setpoints (potentiometers, 4-20 mA loops via external resistor) with hardware-averaged oversampling. Multiple UART channels enable RS-232/RS-485 communication with PLCs and motor drives, while the integrated comparators detect overcurrent or overtemperature faults. The -40C to +85C industrial temperature range handles factory floor environments. Place decoupling capacitors close to Vdd/Vss pins and route the ICSP PGD/PGC lines to a programming header for field firmware updates.
Recommended
Home Appliance Control Board
The PIC18LF55K42T-I/PT fits home appliance control boards - washing machines, dishwashers, ovens, and air conditioners - where its 8-bit PIC core reliably executes motor sequencing, user-interface handling, and safety monitoring. The 64 MHz MIPS performance handles BLDC or stepper motor commutation via CCP/ECCP PWM modules, while the 12-bit ADC reads thermistor and water-level sensors with adequate resolution. DMA channels move ADC samples to RAM without CPU intervention, enabling precise timing for triac-based heater control and zero-cross detection. XLP low-power modes support standby power below 100 mW for Energy Star compliance. The 44 I/O pins interface with rotary encoders, capacitive touch pads, buzzer drivers, and seven-segment LED displays commonly found on appliance front panels.
Recommended
Battery-Powered Medical Device
The PIC18LF55K42T-I/PT is appropriate for battery-powered medical and wellness devices - portable pulse oximeters, glucose meters, and electronic stethoscopes - thanks to its 1.8-3.6 V Vdd supporting 2xAA or single-cell Li-ion, and XLP technology delivering sub-uA sleep current. The 12-bit ADC2 with computation provides oversampled, hardware-averaged sensor readings critical for SpO2 or glucose photodiode signals, reducing noise in low-light measurements. Vector interrupts allow the CPU to remain in sleep until a sensor event triggers wake-up, dramatically extending battery life. The 256-byte EEPROM stores calibration coefficients and patient data without external memory. The 48-pin TQFP-EP provides a small footprint for handheld enclosures, and the exposed pad aids thermal dissipation during peak CPU activity.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC18LF55K42T-I/PT is suitable for non-safety automotive body electronics - interior lighting controllers, seat heaters, mirror adjusters, and accessory modules - when used within its 1.8-3.6 V supply range with an external 12 V-to-3.3 V regulator. The 64 MHz PIC core processes LIN-bus messages and PWM dimming commands in real time. The 12-bit ADC2 with computation reads thermistor inputs for seat temperature feedback, while multiple CCP/ECCP PWM channels drive LED drivers and small DC motors. Note that this part is not AEC-Q100 qualified - for safety-critical or under-hood applications, choose a Microchip AEC-Q100 K42 variant. The -40C to +85C industrial temperature range handles cabin environments comfortably. Place TVS diodes on supply and signal lines for automotive transient protection.
Recommended
USB Human Interface Device (HID)
When paired with the PIC18F55K42 family member that includes a USB 2.0 full-speed peripheral module, the PIC18LF55K42T-I/PT's architectural sibling serves as a USB HID controller - keyboards, mice, game controllers, and custom input devices. The 64 MHz CPU handles USB protocol stack, HID report generation, and LED/buzzer feedback within timing budgets. The 32 KB Flash accommodates USB stacks and HID descriptors; 2 KB RAM handles endpoint buffers and HID reports. The 12-bit ADC reads analog joystick axes with sufficient resolution for gaming input. Multiple CCP/ECCP PWM channels drive RGB LED feedback for keyboards and headsets. The 48-pin TQFP-EP fits compact consumer enclosures. The DMA controller can move HID reports from RAM to USB endpoint without CPU, enabling low-latency interrupt-driven designs.
Recommended
Motor Control / Fan Drive
The PIC18LF55K42T-I/PT is an excellent fit for low-power motor control applications - small BLDC fans, stepper motor drivers, and DC motor speed controllers - where its 64 MHz core executes field-oriented control (FOC) or trapezoidal commutation algorithms. The 12-bit ADC2 with computation reads back-EMF or shunt current for closed-loop control, while DMA channels offload ADC-to-CCP triggering for hardware-based commutation timing. Multiple ECCP/CCP PWM channels generate complementary outputs with programmable dead-time for driving three-phase bridges or H-bridges. The 1.8-3.6 V supply range supports small 3 V brushless fans commonly used in networking equipment and consumer electronics. XLP sleep modes enable standby fan-off with sub-uA current draw when the system is idle.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF55K42T-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF55K42-I/PT | PIC18F55K42T-I/PT | PIC18LF55K42-E/PT | PIC18LF47K42-I/MV |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 48-pin TQFP-EP (7x7) | 48-pin TQFP (7x7) | 48-pin TQFP-EP (7x7) | 48-pin TQFP (7x7) | 48-pin TQFP-EP (7x7) |
| Operating Voltage (Vdd) | 1.8 V to 3.6 V | 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 |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| CPU Clock Speed | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| I/O Pins | 44 | 44 | 44 | 44 | 36 |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +125C (Extended) | -40C to +85C |
| DMA | Yes | Yes | Yes | Yes | Yes |
| Price (1-piece, USD) | 4.62 | 4.45 | 4.85 | 5.20 | 4.10 |
Key Differentiators
- Lowest voltage range (1.8V min) in PIC18 K42 family for coin-cell applications (vs PIC18F55K42T-I/PT)
- Industrial-grade operating temperature range standard (vs PIC18LF55K42-E/PT)
- Highest I/O count (44) in 48-pin PIC18 K-series (vs PIC18LF47K42-I/MV)
Design Notes
Estimated: Vdd decoupling requires at minimum one 100 nF ceramic capacitor close to each Vdd pin (5 Vdd pins on this 48-pin TQFP-EP), plus a 10 uF bulk capacitor at the regulator output. Place the 100 nF caps within 3 mm of each Vdd pin to suppress switching transients when the 64 MHz core or PWM outputs toggle. For XLP low-power designs, the bulk capacitor value directly affects wake-up time from sleep - values above 10 uF may delay regulator stabilization.
The exposed thermal pad (EP) on the bottom of the TQFP-48 package must be soldered to the PCB ground plane for proper thermal dissipation. Without the EP connected, junction temperature can rise 30-50C above ambient under continuous 64 MHz operation, potentially triggering thermal shutdown at high ambient temperatures. Use at least 8 thermal vias (0.3 mm drill) connecting the EP to inner ground planes. For 1.8 V operation, power dissipation is typically below 50 mW even at full CPU load.
Route the ICSP programming lines (PGD/PGC on RB6/RB7) with short, direct traces to a 6-pin programming header. Keep PGD and PGC trace lengths matched within 25 mm to avoid timing skew during high-speed programming. Add a 10 kohm pull-up on MCLR to ensure proper reset behavior. Place the programming connector at the board edge for in-system programming access. Consider adding test points on Vdd, Vss, and MCLR for debug probing.
Do not apply 5 V to Vdd on the LF (low-voltage) variant - the PIC18LF55K42 has a maximum Vdd of 3.6 V. Exceeding this risks latch-up or permanent damage. For 5 V designs, use the PIC18F55K42 variant. Also note that the LF version does not include the USB peripheral; for USB applications, choose the PIC18F55K42 family. The 1.8 V minimum Vdd requires the BOR (brown-out reset) to be configured correctly in the configuration bits to avoid unreliable startup on slowly rising power supplies.
Place the external crystal (if used) within 10 mm of OSC1/OSC2 pins and surround it with a ground pour to minimize EMI. Add 10 pF-33 pF load capacitors (per crystal datasheet) between each OSC pin and ground. Avoid routing high-frequency digital signals or PWM outputs across the oscillator traces. For ADC accuracy, separate analog and digital Vdd/Vss traces; the 12-bit ADC2 with computation can achieve 12 ENOB when the analog supply is properly filtered.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - for automotive safety applications, choose AEC-Q100 qualified variants. Industrial temperature grade only - not military/aerospace qualified.
