PIC18F55K42-I/PT - 8-Bit 64MHz 32KB Flash MCU 48-TQFP-EP | Microchip
MPN: PIC18F55K42-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.16 | $3.16 |
| 10 | $2.85 | $28.50 |
| 100 | $2.54 | $254.00 |
| 500 | $2.27 | $1,135.00 |
| 1,000 | $2.05 | $2,050.00 |
PIC18F55K42-I/PT Overview
A PIC microcontroller (Programmable Interface Controller, or MCU) is a compact, low-cost, low-power embedded computer built around a Harvard-architecture RISC core with on-chip Flash, RAM, EEPROM, and a peripheral set (timers, ADC, communications). It belongs to the microcontroller > embedded MCU > semiconductor hierarchy and serves as the central processing unit of countless consumer, industrial, automotive, and IoT systems. PIC18F devices are Microchip's mid-range 8-bit family with 16-bit instructions and rich interrupt handling, bridging the gap between PIC16 baseline parts and PIC24/dsPIC 16-bit devices.
Key features of the PIC18F55K42 include 49 digital I/O pins, multiple serial interfaces (UART, SPI, I2C), 12-bit ADC2 with up to 43 analog channels, multiple 8/16-bit timers, DMA controller, vectored interrupt controller, and an on-chip 64 MHz internal oscillator. The XLP technology delivers nanoWatt sleep currents suitable for battery applications, while core independent peripherals (CLC, NCO, PWM, SMT, CCP) can operate without CPU intervention.
Typical applications include industrial sensor nodes, low-power IoT edge devices, home appliance control boards, automotive body and lighting modules, USB/HID peripherals, and consumer electronics requiring 5 CAN communication over multiple serial protocols. The wide 2.5 V to 5.5 V supply range and small TQFP-EP footprint simplify layout in space-constrained multi-layer PCBs.
When designing with the PIC18F55K42-I/PT, allocate adequate ground copper under the exposed pad (EP) to dissipate package thermal power and to provide a low-impedance ground return. Use Microchip's MPLAB X IDE and XC8 compiler for code development; the device is supported by all major PIC programmers/debuggers including ICD 4, PICkit 4, and MPLAB SNAP.
This page synthesizes verified distributor pricing, drop-in same-package alternatives (PIC18F46K42, PIC18F56K42, PIC18F57K42 from the same family), and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC18F55K42-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 PIC18F55K42-I/PT (same form factor and footprint) — differing in Package, ADC, Program Memory (Flash), Comparators, DAC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F56K42-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F57K42-I/PT
✅ Drop-In✓ In Stock
$2.72 / Unit
View Datasheet →PIC18F46K42-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F45K42-I/PT
✅ Drop-In✓ In Stock
$1.52 / Unit
View Datasheet →PIC18F47K42-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F47Q84-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F55K42-I/PT Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| CPU Speed | 64 MHz (16 MIPS) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 256 B |
| Package | 48-pin TQFP-EP (7x7 mm) |
| Operating Voltage Range | 2.5 V to 5.5 V |
| I/O Pins | 49 |
| ADC | 12-bit ADC2 with computation |
| ADC Channels | Up to 43 |
| Timers | Multiple 8-bit / 16-bit |
| Serial Interfaces | UART, SPI, I2C |
| DMA | Yes |
| Operating Temperature | -40C to +85C (Industrial) |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
PIC18F55K42-I/PT Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) - active-low input, internal pull-up |
| Pin 2 | RA0 — Digital I/O / analog input AN0 |
| Pin 3 | RA1 — Digital I/O / analog input AN1 |
| Pin 4 | RA2 — Digital I/O / analog input AN2 |
| Pin 5 | RA3 — Digital I/O / analog input AN3 / VREF+ |
| Pin 6 | RA4 — Digital I/O / analog input AN4 |
| Pin 7 | VSS — Ground reference |
| Pin 8 | VDD — Positive supply voltage (2.5-5.5 V) |
| Pin 9 | RA5 — Digital I/O / analog input AN5 |
| Pin 10 | RA6 — Digital I/O / analog input AN6 |
| Pin 11 | RA7 — Digital I/O / analog input AN7 |
| Pin 12 | RB0 — Digital I/O / analog input AN8 / IOC |
| Pin 13 | RB1 — Digital I/O / analog input AN9 |
| Pin 14 | RB2 — Digital I/O / analog input AN10 |
| Pin 15 | RB3 — Digital I/O / analog input AN11 |
| Pin 16 | RB4 — Digital I/O / analog input AN12 |
| Pin 17 | RB5 — Digital I/O / analog input AN13 |
| Pin 18 | RB6 — Digital I/O / ICSPCLK (programming clock) |
| Pin 19 | RB7 — Digital I/O / ICSPDAT (programming data) |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage (2.5-5.5 V) |
| Pin 22 | RC0 — Digital I/O / analog input AN14 |
| Pin 23 | RC1 — Digital I/O / analog input AN15 |
| Pin 24 | RC2 — Digital I/O / analog input AN16 |
| Pin 25 | VSS — Ground reference |
| Pin 26 | VDD — Positive supply voltage (2.5-5.5 V) |
| Pin 27 | RC3 — Digital I/O / analog input AN17 |
| Pin 28 | RC4 — Digital I/O / analog input AN18 |
| Pin 29 | RC5 — Digital I/O / analog input AN19 |
| Pin 30 | RC6 — Digital I/O / analog input AN20 |
| Pin 31 | RC7 — Digital I/O / analog input AN21 |
| Pin 32 | RD0 — Digital I/O / analog input AN22 |
| Pin 33 | RD1 — Digital I/O / analog input AN23 |
| Pin 34 | RD2 — Digital I/O / analog input AN24 |
| Pin 35 | RD3 — Digital I/O / analog input AN25 |
| Pin 36 | RD4 — Digital I/O / analog input AN26 |
| Pin 37 | RD5 — Digital I/O / analog input AN27 |
| Pin 38 | RD6 — Digital I/O / analog input AN28 |
| Pin 39 | RD7 — Digital I/O / analog input AN29 |
| Pin 40 | RE0 — Digital I/O / analog input AN30 |
| Pin 41 | RE1 — Digital I/O / analog input AN31 |
| Pin 42 | RE2 — Digital I/O / analog input AN32 |
| Pin 43 | RE3 — Digital I/O / analog input AN33 |
| Pin 44 | VSS — Ground reference |
| Pin 45 | VDD — Positive supply voltage (2.5-5.5 V) |
| Pin 46 | RF0 — Digital I/O / analog input AN34 |
| Pin 47 | RF1 — Digital I/O / analog input AN35 |
| Pin 48 | EP — Exposed thermal pad - must be soldered to ground pour for thermal/electrical performance |
Typical Applications
PIC18F55K42-I/PT is suitable for 6 applications: Industrial Sensor Hub and Monitoring Node, Low-Power IoT Edge Device, Home Appliance Control Board, Automotive Body and Lighting Module, USB/HID Peripheral and Human Interface Device, Consumer Electronics with Display and Touch.
Industrial Sensor Hub and Monitoring Node
The PIC18F55K42-I/PT is well matched to industrial sensor hubs because it combines a 64 MHz 16 MIPS core with up to 43 analog channels of 12-bit ADC2 to scan multiple analog sensors (temperature, pressure, current) in a single scan loop. Its 32 KB Flash and 2 KB SRAM comfortably host Modbus RTU or CANopen firmware plus a small RTOS or state machine. The 2.5-5.5 V supply range simplifies integration with both 3.3 V and 5 V industrial backplanes, and the XLP deep-sleep modes reduce idle power for solar-powered remote nodes.
Recommended
Low-Power IoT Edge Device
The PIC18F55K42-I/PT's XLP nanoWatt sleep modes (down to tens of nA with RTC running) make it an excellent host for battery-powered IoT edge devices such as wireless environmental sensors, smart locks, and asset trackers. DMA + core independent peripherals let the device wake, sample, encrypt, and transmit without waking the CPU, dramatically extending battery life. The wide 2.5-5.5 V supply range supports direct connection to a single Li-ion cell or two AA cells in series. Its 32 KB Flash is sufficient for lightweight TLS, MQTT-SN, or LoRaWAN device stacks.
Recommended
Home Appliance Control Board
In washing machines, dishwashers, ovens, and HVAC thermostats, the PIC18F55K42-I/PT provides the control brain for motor drivers, user interfaces, and safety sensors. Its 12-bit ADC2 with computation performs oversampling for accurate temperature and current sensing, while its PWM + CCP peripherals drive triac-controlled AC loads and BLDC fans. The 48-pin TQFP-EP package offers ample I/O for keypad scan, LED matrix drive, and rotary encoder input. Robust ESD and EMI performance from the K42 family suit IEC 61000-4-2/4-4 compliant appliance designs.
Recommended
Automotive Body and Lighting Module
Although the PIC18F55K42-I/PT is the industrial-grade variant, its wide operating temperature headroom and robust peripherals support non-safety automotive body applications such as ambient lighting controllers, door modules, mirror controllers, and HVAC blend doors. The 49 I/O pins drive multiple LED strings via PWM while the ADC2 samples potentiometers and current shunts. With AEC-Q100 variants available in the same K42 family (PIC18F55K42-E/PT for extended temperature), designers can migrate to fully automotive-qualified versions on the same footprint.
Recommended
USB/HID Peripheral and Human Interface Device
The PIC18F55K42-I/PT can serve as a USB-HID-class device host (keyboard, mouse, game controller, custom HID) when paired with an external USB transceiver and the Microchip USB stack for PIC18. Its 64 MHz core, 2 KB SRAM, and 32 KB Flash accommodate USB enumeration, HID report descriptors, and complex human-interface state machines. CLC (Configurable Logic Cell) and DMA offload button scanning and LED PWM updates from the CPU, reducing interrupt latency and improving HID polling-rate jitter.
Recommended
Consumer Electronics with Display and Touch
For consumer appliances with segment LCD or small TFT displays, the PIC18F55K42-I/PT provides enough GPIO to drive LCD segment lines, capacitive touch buttons via the CVD module, and rotary UI inputs. Its low power consumption in sleep modes makes it ideal for always-on mains-powered or rechargeable consumer devices. The 32 KB Flash and 2 KB SRAM support full color UI state machines and BLE pairing flows via a companion module.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F55K42-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F56K42-I/PT | PIC18F57K42-I/PT | PIC18F46K42-I/PT | PIC18F45K42-I/PT | PIC18F47K42-I/PT |
|---|---|---|---|---|---|---|
| Package | 48-pin TQFP-EP (7x7 mm) | 48-pin TQFP-EP (7x7 mm) - same | 48-pin TQFP-EP (7x7 mm) - same | 48-pin TQFP-EP (7x7 mm) - same | 48-pin TQFP-EP (7x7 mm) - same | 48-pin TQFP-EP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 64 KB | 128 KB | 16 KB | 32 KB | 128 KB |
| SRAM | 2 KB | 4 KB | 8 KB | 1 KB | 2 KB | 8 KB |
| CPU Speed | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS | 64 MHz / 16 MIPS |
| Operating Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V |
| I/O Pins | 49 | 49 | 49 | 44 | 44 | 49 |
| Unit Price (1pc, as of 2026-09-28) | $3.16 | ~$3.60 | ~$4.50 | ~$2.80 | ~$2.95 | ~$4.40 |
Key Differentiators
- Highest memory in 48-pin K42 family without going to 64-pin packages (vs PIC18F46K42-I/PT)
- Lower cost vs larger Flash siblings (vs PIC18F57K42-I/PT)
- Complete peripheral parity across the K42 family (vs PIC18F47K42-I/PT)
Design Notes
Solder the exposed thermal pad (EP, pin 48) of the TQFP-EP package to a continuous ground copper pour on the top layer (at least 1 cm x 1 cm recommended). This provides a low-impedance ground return and a thermal dissipation path for the silicon die. Without proper EP soldering, junction temperature may rise 15-20C above ambient, reducing long-term reliability. Use multiple thermal vias (typically 9-16 vias in a 3x3 to 4x4 grid, 0.3 mm drill) to stitch the EP to internal ground planes.
Place 100 nF ceramic decoupling capacitors as close as possible to every VDD pin (pins 8, 21, 26, 45) and a single 10 uF bulk capacitor near the device. The PIC18F55K42 has four VDD pins that must all be connected; missing one can cause erratic behavior or latch-up under load transients. For battery applications using XLP sleep modes, add a 1 uF reservoir capacitor on VDD to support peak load currents when waking from sleep before the main regulator stabilizes.
Keep the ICSP programming pins (RB6/ICSPCLK and RB7/ICSPDAT) accessible on the PCB - either with a 2x3 or 1x6 header or test pads - to allow in-circuit programming and debugging. RB6 and RB7 default to programming mode only when MCLR is held low; otherwise they are general-purpose I/O. Route the 32.768 kHz secondary oscillator traces (if used for RTC) short and guard them with ground to minimise noise coupling into the low-power timer.
Do not confuse the /PT suffix (TQFP package) with /P (PDIP) or /SP (SPDIP). The /I temperature grade is -40C to +85C industrial; for -40C to +125C extended grade use /E. Configuring peripherals (e.g., ADC, PWM, UART) without first unlocking IOLOCK / PPS registers is a common beginner pitfall - always include the PPS unlock sequence in your firmware init code. Finally, never tie MCLR directly to VDD without a pull-up; the internal weak pull-up is enabled by configuration bit but an external 10 kohm pull-up is best practice.
Compliance Information
RoHS compliant per Microchip product page. /PT suffix denotes lead-free TQFP packaging. AEC-Q100 qualified automotive variants exist in the same K42 family (PIC18F55K42-E/PT with /E extended temperature grade).
