PIC18LF26K42-I/SO - 64KB Flash 8-bit XLP MCU | Microchip
MPN: PIC18LF26K42-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.11 | $3.11 |
| 10 | $2.8 | $28.00 |
| 100 | $2.45 | $245.00 |
| 500 | $2.15 | $1,075.00 |
| 1,000 | $1.92 | $1,920.00 |
PIC18LF26K42-I/SO Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory, and programmable I/O peripherals. PIC18F/LF K-series MCUs target low-power embedded applications where sleep current, active efficiency, and integrated analog peripherals reduce external component count. The 'LF' variant denotes a low-voltage core (1.8-3.6V), while the 'F' variant extends to 5V. These MCUs sit within Microchip's 8-bit PIC18 hierarchy: PIC10/16 baseline -> PIC18 enhanced -> PIC18 K-series low-power -> PIC18F/LFxxK42 sub-family with rich peripherals.
Key features include eXtreme Low Power (XLP) technology with sub-uA sleep currents, 64KB self-programmable Flash, 4KB SRAM, 1KB EEPROM, 12-bit ADC with computation, 5-bit DAC, multiple communication peripherals (I2C/SPI/UART), and 25mA source/sink capability per I/O. The 28-SOIC package offers easy hand-soldering and breadboard compatibility for prototype work.
The PIC18LF26K42 uses a RISC architecture with a 16-bit instruction word and 8-bit data path, optimized for deterministic interrupt response and C-compiler efficiency. The integrated DMA controller offloads data movement from the CPU, freeing cycles for application logic. The device supports ICSP (In-Circuit Serial Programming) and debug via ICD.
Typical applications include IoT sensor nodes, battery-powered wearables, home automation, industrial control, USB-to-UART bridges, and low-power wireless sensor hubs. Its XLP technology enables years of operation on coin-cell batteries.
When designing, ensure decoupling capacitors (100nF plus 1uF) are placed within 5mm of VDD pins, and connect all unused I/O to defined logic levels (not floating) to minimize current draw.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18LF26K42-I/SO — 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 PIC18LF26K42-I/SO (same form factor and footprint) — differing in ADC, Package, Core Architecture, Family, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F26K42-I/SO
✅ Drop-In✓ In Stock
$1.43 / Unit
View Datasheet →PIC18LF26K42-I/SP
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →PIC18LF26K42-I/SS
✅ Drop-In✓ In Stock
$2.02 / Unit
View Datasheet →PIC18LF26K40-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF25K42-I/SO
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →PIC18F25K42-I/SO
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →PIC18LF26K42-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC18F/LF K42 (XLP) |
| Flash Program Memory | 64 KB (32K x 16) |
| SRAM | 4 KB |
| EEPROM | 1 KB |
| Maximum CPU Speed | 64 MHz |
| Operating Voltage (LF) | 1.8 V to 3.6 V |
| I/O Pins | 25 |
| ADC | 12-bit ADC2 (multiple channels) |
| DAC | 5-bit DAC |
| Comparators | Yes (integrated) |
| DMA Channels | Yes (Direct Memory Access) |
| PWM Channels | Yes (multiple) |
| Communication Peripherals | I2C, SPI, UART/USART |
| Package | 28-pin SOIC (SO), wide-body 7.50 mm |
| Mounting Type | Surface Mount |
| Operating Temperature (Industrial) | -40 C to +85 C |
| XLP Sleep Current | Sub-microamp (per XLP family datasheet) |
| I/O Source/Sink | 25 mA per pin |
| Programming/Debug | ICSP, ICD (2-wire) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC18LF26K42-I/SO Pin Configuration
| Pin 1 | RA5 — Digital I/O port A bit 5 / analog input |
| Pin 2 | RA4 — Digital I/O port A bit 4 |
| Pin 3 | RA3 — Digital I/O port A bit 3 / analog input |
| Pin 4 | RA2 — Digital I/O port A bit 2 / analog input |
| Pin 5 | RA1 — Digital I/O port A bit 1 / analog input |
| Pin 6 | RA0 — Digital I/O port A bit 0 / analog input |
| Pin 7 | VSS — Ground reference |
| Pin 8 | RA7 — Digital I/O port A bit 7 / oscillator |
| Pin 9 | RA6 — Digital I/O port A bit 6 / oscillator |
| Pin 10 | RC0 — Digital I/O port C bit 0 |
| Pin 11 | RC1 — Digital I/O port C bit 1 |
| Pin 12 | RC2 — Digital I/O port C bit 2 |
| Pin 13 | RC3 — Digital I/O port C bit 3 / SCL |
| Pin 14 | RC4 — Digital I/O port C bit 4 / SDA |
| Pin 15 | RC5 — Digital I/O port C bit 5 |
| Pin 16 | RC6 — Digital I/O port C bit 6 / TX |
| Pin 17 | RC7 — Digital I/O port C bit 7 / RX |
| Pin 18 | VSS — Ground reference (secondary) |
| Pin 19 | VDD — Positive supply voltage (1.8V-3.6V) |
| Pin 20 | RB0 — Digital I/O port B bit 0 / INT |
| Pin 21 | RB1 — Digital I/O port B bit 1 |
| Pin 22 | RB2 — Digital I/O port B bit 2 |
| Pin 23 | RB3 — Digital I/O port B bit 3 |
| Pin 24 | RB4 — Digital I/O port B bit 4 |
| Pin 25 | RB5 — Digital I/O port B bit 5 |
| Pin 26 | RB6 — Digital I/O port B bit 6 / ICSCLK |
| Pin 27 | RB7 — Digital I/O port B bit 7 / ICSDAT |
| Pin 28 | VSS — Ground reference (primary) |
Typical Applications
PIC18LF26K42-I/SO is suitable for 7 applications: Battery-Powered IoT Sensor Node, Home Automation Controller, Industrial Control & HMI Interface, Wearable Health & Fitness Device, USB-to-UART Bridge Replacement (Firmware-Based), Low-Power Wireless Sensor Hub, Automotive Body & Comfort Electronics.
Battery-Powered IoT Sensor Node
The PIC18LF26K42-I/SO is an ideal MCU for battery-powered IoT sensor nodes thanks to its XLP (eXtreme Low Power) technology with sub-microamp sleep currents and integrated 12-bit ADC2. The 64KB Flash supports OTA firmware updates and complex sensor-fusion algorithms, while 4KB RAM buffers streaming sensor data. Operating from 1.8V-3.6V lets it run directly from 2x AA alkaline cells or a single Li-Ion cell without boost converters, increasing system efficiency by 5-10% versus 5V-core MCUs. Its 25 I/O pins accept multiple sensor inputs (temperature, humidity, motion) and drive low-power radios like LoRa or BLE via SPI/UART. The integrated DMA offloads sensor reads from the CPU, keeping wake time short and average current in the tens of microamps.
Recommended
Home Automation Controller
The PIC18LF26K42-I/SO fits home automation controllers requiring reliable 3.3V operation, multiple communication interfaces, and rich analog peripherals for HVAC and lighting control. Its 64KB Flash and 4KB RAM support firmware stacks for Zigbee, BLE, or Wi-Fi co-processor management over UART/SPI. The 12-bit ADC2 reads analog sensors (light, temperature, current sensing), while 5-bit DAC outputs analog control voltages for dimmers and motor drivers. PIC18 hardware integrity (vector interrupts, WDT, code protection) ensures robust operation in always-on residential deployments. The 28-SOIC package is hand-solderable for prototyping and easily placed on 2-layer consumer PCBs.
Recommended
Industrial Control & HMI Interface
The PIC18LF26K42-I/SO operates reliably in industrial environments with its -40C to +85C industrial temperature range and integrated analog peripherals for sensor interfaces and HMI. Its 64KB Flash holds industrial protocol stacks (Modbus RTU, CANopen via SPI-to-CAN bridge), while 4KB RAM manages display buffers and PID control loops. The DMA controller handles high-speed ADC sampling (up to 100 ksps) without CPU intervention, freeing resources for control logic. The 25mA source/sink I/O directly drive relays, optocouplers, and LED indicators without external drivers. Compared to 5V-only MCUs, the LF core's 1.8V minimum supports modern 1.8V sensor interfaces natively.
Recommended
Wearable Health & Fitness Device
The PIC18LF26K42-I/SO is well-suited for wearable health and fitness devices where sub-microamp sleep currents and small PCB footprint matter most. Its 1.8V-3.6V operation runs directly from coin-cell batteries (CR2032) lasting 1-3 years in typical fitness-band duty cycles. The 12-bit ADC2 with computation performs on-chip signal processing for heart-rate (PPG), temperature, and motion sensors, while DMA offloads these readings from the CPU. The 64KB Flash supports Bluetooth Low Energy stack (via external module) and on-device activity classification algorithms. The 28-SOIC package, while not as compact as QFN, is acceptable for wearables with 25mm+ board area.
Recommended
USB-to-UART Bridge Replacement (Firmware-Based)
Although the PIC18LF26K42 lacks native USB, it serves as a cost-effective UART-to-SPI/I2C bridge controller in industrial gateways where USB is handled by a companion IC. Its 64KB Flash implements custom protocol conversion, while 4KB RAM buffers packets. The 25 I/O pins support multiple peripheral interfaces simultaneously. Pair with the PIC18F14K50 or FTDI FT232 for USB host-side communication. The K42's DMA and rich interrupt controller outperform older PIC16F bridges in throughput and latency. The 28-SOIC package is widely supported on standard USB-stick form-factor PCBs.
Recommended
Low-Power Wireless Sensor Hub
The PIC18LF26K42-I/SO functions as a low-power wireless sensor hub aggregating data from multiple SPI or I2C sensor slaves, processing locally, and forwarding via UART to a long-range radio module. Its XLP technology with sub-microamp sleep current enables duty-cycled operation where the MCU wakes briefly to sample sensors, processes data, transmits, and returns to sleep - achieving average currents under 50uA. The 64KB Flash supports over-the-air (OTA) firmware update protocols, while 4KB RAM buffers sensor bursts. The DMA controller manages simultaneous sensor reads without CPU overhead, extending battery life by 20-30% versus polling-based designs. Compatible with LoRa, Sigfox, NB-IoT, and BLE module ecosystems.
Recommended
Automotive Body & Comfort Electronics
While the standard PIC18LF26K42 is not AEC-Q100 qualified, its design is widely used in non-safety automotive body and comfort applications (interior lighting, seat controls, HVAC panels) at 3.3V. Its 12-bit ADC2 reads multiple analog sensors (potentiometers, thermistors), while PWM outputs drive LED drivers and small DC motor controllers. The 64KB Flash supports LIN (Local Interconnect Network) slave protocol stacks via UART, and the 25 I/O pins interface with H-bridges and relay arrays. For AEC-Q100-qualified variants, Microchip offers the PIC18F26K42-I/SO in automotive grade. The 28-SOIC package suits space-constrained automotive PCBs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF26K42-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F26K42-I/SO | PIC18LF26K40-I/SO | PIC18LF25K42-I/SO | PIC18F25K42-I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (SO) | 28-SOIC (SO) - same | 28-SOIC (SO) - same | 28-SOIC (SO) - same | 28-SOIC (SO) - same |
| Core Voltage | 1.8V-3.6V (LF) | 2.3V-5.5V (F) | 1.8V-3.6V (LF) | 1.8V-3.6V (LF) | 2.3V-5.5V (F) |
| Flash Memory | 64 KB | 64 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 4 KB | 4 KB | 2 KB | 2 KB | 2 KB |
| Max CPU Speed | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| I/O Pins | 25 | 25 | 25 | 24 | 24 |
| ADC Resolution | 12-bit ADC2 | 12-bit ADC2 | 12-bit ADC2 | 12-bit ADC2 | 12-bit ADC2 |
| DMA Controller | Yes | Yes | Yes | Yes | Yes |
| Approx. Unit Price (USD) | $3.11 | ~$3.20 | ~$2.80 | ~$2.90 | ~$2.95 |
Key Differentiators
- Largest Flash in PIC18 K42 28-pin SOIC family (vs PIC18LF26K40-I/SO)
- Low-voltage core for battery-powered designs (vs PIC18F26K42-I/SO)
- Newer K42 architecture with DMA and 12-bit ADC2 (vs PIC18LF26K22-I/SO)
- Higher I/O count in same package (vs PIC18LF25K42-I/SO)
Design Notes
The PIC18LF26K42's XLP technology achieves sub-microamp sleep current (typical 30-100 nA in Sleep mode with RTCC, no peripherals active). For lowest power, disable unused peripherals via PMD (Peripheral Module Disable) registers, switch unused I/O to outputs driving defined levels (not floating), and use the LF's 1.8V minimum VDD instead of 3.3V where possible - active current scales with VDD. Average current in typical IoT duty cycles (1 wake/sec) is 5-20 uA. Use the on-board Low-Power Sleep with RTCC for sensor-timed wakeups.
Place a 100nF decoupling capacitor within 5mm of each VDD pin, plus a single 1uF to 10uF bulk capacitor near the IC. Connect all VSS pins to a single ground plane via short traces; do not daisy-chain grounds. Place the ICSP/ICD connector (6-pin RJ-12 or 0.1" header) at the board edge for programming access. For SOIC packages, ensure trace clearance of at least 0.2mm between adjacent pads to prevent solder bridges during reflow.
Do not apply 5V signals to PIC18LF26K42 I/O pins - the LF core is 3.3V-max. For 5V-tolerant designs, choose the PIC18F26K42 (5V core) instead. Ensure MCLR is pulled high through a 10k resistor (do not leave floating) for reliable operation. When using the internal oscillator, configure OSCCON correctly for the target F_CPU; the default 1MHz HFINTOSC may be slower than expected without CONFIG1 tuning. Never connect AVss/AVdd pins to wrong rails; AVss must tie to Vss and AVdd to Vdd.
For SPI bus speeds above 8 MHz, keep trace lengths under 50mm and use a ground reference plane beneath the SPI traces. The PIC18LF26K42's SPI peripheral supports up to F_CPU/2 in Master mode. For I2C buses exceeding 100 kHz, calculate pull-up resistor values using R = (Vdd - 0.4V) / (3 * Cbus * Fscl) to meet rise-time requirements; 4.7k is typical for 100 kHz with <100 pF bus capacitance.
Route the ICSP clock (ICSCLK, RB6) and data (ICSDAT, RB7) lines away from high-current switching traces to prevent programming failures. If using the secondary oscillator (SOSC), keep the crystal traces short and symmetric with the load capacitors placed within 3mm of the OSC1/OSC2 pins. For analog inputs (RA0-RA5), use guard traces or ground pours to isolate from digital noise; the 12-bit ADC2 achieves best ENOB with input source impedance below 1k ohm.
Compliance Information
RoHS compliant per Microchip product page and DigiKey listing. Not AEC-Q100 qualified - choose automotive-grade PIC18F26K42-I/SO with AEC-Q100 for vehicle applications. Lead-free and halogen-free per Microchip packaging specifications.
