PIC18LF27K42-I/SO - 8-bit 64MHz 128KB Flash XLP MCU | Microchip
MPN: PIC18LF27K42-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.1 | $3.10 |
| 10 | $2.78 | $27.80 |
| 100 | $2.32 | $232.00 |
| 500 | $2.01 | $1,005.00 |
| 1,000 | $1.78 | $1,780.00 |
PIC18LF27K42-I/SO Overview
An 8-bit microcontroller (MCU) is a small computer-on-a-chip integrating a CPU, RAM, non-volatile program memory (Flash), EEPROM data memory, and peripherals such as ADC, timers, UART, SPI and I2C. MCUs belong to the broader class of microcontrollers, which sit within embedded processors and, ultimately, the wider semiconductor device hierarchy. The 'XLP' (eXtreme Low Power) designation indicates that this PIC18 family was designed for battery-powered applications, with nanoWatt sleep modes and active-mode currents in the microamp range.
Key features of the PIC18LF27K42 include 25 general-purpose I/O pins, a 12-bit differential ADC with computation (ADC2), up to four 8-bit DAC outputs, multiple PWM/Capture/Compare peripherals, two I2C/SPI and one UART module, and Core Independent Peripherals (CIPs) such as CLC, NCO and DMA-friendly signal routing. The high-precision 32 MHz internal oscillator and PLL enable operation up to 64 MHz without an external crystal. CIPs allow complex timing, logic and waveform generation without CPU intervention, reducing active time and total energy.
Architecturally, the PIC18LF27K42 uses a Harvard-class 8-bit RISC core with a hardware multiplier and a 31-level stack. A built-in CRC with memory scan supports IEC 60730 class-B safety software in household appliances. The K42 family adds a 12-bit differential ADC2 with averaging, oversampling and hardware accumulation, significantly simplifying sensor acquisition firmware.
Typical applications include IoT sensor nodes, low-power wireless remotes, white-goods and appliance control, lithium-battery medical wearables, automotive body and lighting subsystems (non-Automotive-AEC-Q100 variant), and small motor-control or fan-control boards. When designing with this device, place the 0.1 µF VDD decoupling capacitor within 5 mm of each VDD/SS pin pair, and use the internal LDO plus brown-out reset rather than an external supervisor to minimise BOM. This page synthesises distributor pricing, same-package alternatives and design considerations not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC18LF27K42-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 PIC18LF27K42-I/SO (same form factor and footprint) — differing in ADC, Package, DAC, Comparators, PWM Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF27K42-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF27K42-E/SO
✅ Drop-In✓ In Stock
$2.4 / Unit
View Datasheet →PIC18LF27K42T-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF26K42-I/SO
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18LF27K40-I/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18LF27K42-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit RISC, Harvard) |
| Family | PIC18(L)FxxK42 (XLP) |
| Maximum CPU Frequency | 64 MHz |
| Program Memory (Flash) | 128 KB (64K x 16) |
| Data SRAM | 8 KB |
| Data EEPROM | 1 KB |
| Supply Voltage (VDD) | 1.8 V to 3.6 V |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| Number of I/O Pins | 25 |
| ADC | 12-bit differential ADC2 with computation |
| DAC | Up to 4 x 8-bit DAC |
| Package | 28-pin SOIC (300 mil, SO) |
| Mounting Type | Surface Mount |
| Communication Peripherals | 2x I2C/SPI, 1x UART/USART |
| Core Independent Peripherals | CLC, NCO, PWM, CRC, DMA-friendly routing |
| Internal Oscillator | 32 MHz HFINTOSC with PLL to 64 MHz |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| MSL Level | 1 |
PIC18LF27K42-I/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — PORTA0 / analog input |
| Pin 3 | RA1 — PORTA1 / analog input |
| Pin 4 | RA2 — PORTA2 / analog input / DAC |
| Pin 5 | RA3 — PORTA3 / analog input / VREF+ |
| Pin 6 | RA4 — PORTA4 / analog input / DAC |
| Pin 7 | RA5 — PORTA5 / analog input / DAC |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7 — PORTA7 / analog input |
| Pin 10 | RA6 — PORTA6 / analog input |
| Pin 11 | RC0 — PORTC0 |
| Pin 12 | RC1 — PORTC1 |
| Pin 13 | RC2 — PORTC2 |
| Pin 14 | RC3 — PORTC3 |
| Pin 15 | RC4 — PORTC4 |
| Pin 16 | RC5 — PORTC5 |
| Pin 17 | RC6 — PORTC6 |
| Pin 18 | RC7 — PORTC7 |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage (1.8–3.6 V) |
| Pin 21 | RB0 — PORTB0 / interrupt-on-change |
| Pin 22 | RB1 — PORTB1 / interrupt-on-change |
| Pin 23 | RB2 — PORTB2 / interrupt-on-change |
| Pin 24 | RB3 — PORTB3 / interrupt-on-change |
| Pin 25 | RB4 — PORTB4 / interrupt-on-change |
| Pin 26 | RB5 — PORTB5 / interrupt-on-change |
| Pin 27 | RB6 — PORTB6 / ICSP PGC |
| Pin 28 | RB7 — PORTB7 / ICSP PGD |
Typical Applications
PIC18LF27K42-I/SO is suitable for 6 applications: IoT Wireless Sensor Node, White Goods and Appliance Control, Battery-Powered Medical Wearable, Low-Power Motor and Fan Controller, Industrial Sensor Hub / Edge Node, Remote Control and HMI Module.
IoT Wireless Sensor Node
The PIC18LF27K42-I/SO is a strong fit for battery-powered IoT sensor nodes thanks to its 1.8 V–3.6 V VDD range, sub-µA XLP nanoWatt sleep currents, and 12-bit differential ADC2 with hardware oversampling. In a typical design it is paired with a sub-GHz radio such as the Microchip MRF89XA or a low-power BLE module via SPI, waking periodically to sample a sensor, buffer samples using DMA-friendly CIP routing, and transmit a short packet before returning to sleep. The 128 KB Flash and 8 KB SRAM comfortably host a wireless stack plus application code. Total sleep current in the nanoWatt Power-down mode is well under 1 µA, enabling multi-year battery life on 2× AA cells.
Recommended
White Goods and Appliance Control
The PIC18LF27K42-I/SO is widely used in white-goods appliance controllers (washing machines, dishwashers, refrigerators) due to its built-in CRC with memory scan supporting IEC 60730 class-B software safety requirements, and its CLC / NCO Core Independent Peripherals that offload timing-critical tasks from the CPU. It drives TRIAC-controlled AC loads, brushed DC motors, and sensor interfaces (NTC, water level). The 12-bit ADC2 with computation accelerates temperature and humidity signal conditioning. Operating from a rectified 5 V or 3.3 V supply, the device's 1.8 V–3.6 V range aligns with typical low-voltage regulators in this category, reducing BOM cost.
Recommended
Battery-Powered Medical Wearable
The PIC18LF27K42-I/SO suits small medical wearables such as pulse-oximeter finger clips, glucose monitors, and portable nebulisers where compact PCB, low power, and on-board data integrity are critical. It integrates a 12-bit differential ADC2 that simplifies direct connection to bio-sensor front-ends (photo-diodes, NTC thermistors, impedance sensors), and the on-chip 4× 8-bit DAC supports reference/bias generation. The XLP nanoWatt modes drop active-mode current to tens of µA/MIPS, allowing multi-day operation on a CR2032 coin cell when paired with efficient firmware duty-cycling. The 128 KB Flash also enables on-board BLE stack code or sensor-fusion algorithms.
Recommended
Low-Power Motor and Fan Controller
For BLDC, brushed DC, or single-phase fan control, the PIC18LF27K42-I/SO's 12-bit ADC2, multiple PWM channels, and NCO (Numerically Controlled Oscillator) provide high-resolution drive and feedback. Combined with CLC-based hardware commutation, motor control loops can run without CPU intervention, allowing the core to sleep most of the time and reducing total energy by 30–60%. The 1.8 V–3.6 V supply range supports direct lithium battery operation in cordless tools and USB-powered fans. The 25 I/O pins also handle Hall sensors, tachometer inputs, and isolated gate-driver signals.
Recommended
Industrial Sensor Hub / Edge Node
In factory-automation edge nodes collecting data from 4–20 mA loops, RTDs, and digital sensors, the PIC18LF27K42-I/SO provides the 12-bit differential ADC2 with hardware averaging, multiple UART/I2C/SPI channels, and the CLC/NCO peripherals for timing-critical tasks. The 28-SOIC package's 300-mil body simplifies hand-repair and probe access in industrial maintenance environments. Its -40 °C to +85 °C industrial temperature range satisfies most control-panel thermal requirements. The 128 KB Flash supports protocol stacks (Modbus RTU, IO-Link device) plus on-board diagnostics, while 8 KB SRAM buffers burst sensor data before forwarding.
Recommended
Remote Control and HMI Module
The PIC18LF27K42-I/SO is well-suited to wireless remote controls, IR/RF key fobs, and small HMI modules with capacitive touch buttons or segmented LED/LCD displays. Its 4× 8-bit DAC outputs provide bias for LED segment drivers, and its PWM outputs drive backlight intensity. The CLC blocks enable hardware debouncing of mechanical switches without CPU wake-up. Its sub-µA sleep current supports multi-year battery life in clicker-style devices, while 128 KB Flash accommodates custom protocol firmware.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF27K42-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF27K42-E/SO | PIC18LF27K42T-I/SO | PIC18LF26K42-I/SO | PIC18LF27K40-I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-pin SOIC (300 mil) | 28-pin SOIC (300 mil) - same | 28-pin SOIC (300 mil) - same | 28-pin SOIC (300 mil) - same | 28-pin SOIC (300 mil) - same |
| Flash | 128 KB | 128 KB | 128 KB | 64 KB | 128 KB |
| SRAM | 8 KB | 8 KB | 8 KB | 8 KB | 8 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| Max CPU Frequency | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| Operating Voltage | 1.8 V – 3.6 V | 1.8 V – 3.6 V | 1.8 V – 3.6 V | 1.8 V – 3.6 V | 1.8 V – 3.6 V |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +125 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| I/O Pins | 25 | 25 | 25 | 25 | 25 |
Key Differentiators
- Extended temperature variant on identical footprint (vs PIC18LF27K42-E/SO)
- Higher Flash density than K42-64 KB variant (vs PIC18LF26K42-I/SO)
- Smaller package area than SPDIP drop-in (vs PIC18LF27K42-I/SP)
Design Notes
Place a 0.1 µF X7R ceramic bypass capacitor within 5 mm of each VDD/SS pin pair (pins 8, 19, 20 in 28-SOIC). Add a bulk 1 µF–10 µF capacitor on VDD for high-current transients during ADC conversions and SPI bus activity. The PIC18LF27K42 LF variant has an internal 3.6 V LDO that supplies the core; keep this bypass scheme tight to avoid regulator instability. Estimated: at 64 MHz CPU and active peripherals, average current is roughly 5–8 mA; sleep current is under 1 µA.
Do not assume the PIC18LF27K42 LF variant can run at 5 V — the absolute maximum VDD is 3.6 V and connecting a 5 V rail will damage the part. Use the PIC18F27K42 F variant for 5 V designs, or add an external LDO regulator. Also, ensure MCLR is pulled high through a 10 kΩ resistor; floating MCLR can cause spurious resets in noisy industrial environments. Finally, the ICSP PGC/PGD pins (RB6/RB7) must remain accessible or a programming header added for field updates.
Estimated: at 64 MHz full operation (8 mA active current) on 3.3 V, total power dissipation is ~26 mW — well within the SOIC-28's thermal envelope (~700 mW). However, in enclosed industrial environments with no airflow, sustained ADC sampling at 200 kSPS combined with continuous SPI activity can push die temperature by 15–20 °C above ambient. Provide a small copper pour under the exposed SOIC pad area and route thermal vias for improved heat spreading in IEC 60730 class-B appliance designs.
Keep analog (PORTA) traces short and isolated from digital switching signals (PORTB, PORTC). Use a ground guard ring around the ADC input pins to reduce digital-coupling noise. Place the ADC reference capacitor (0.1 µF) close to the VREF+ pin. For USB or motor-control applications, isolate switching power ground from analog ground with a star-ground topology. Keep ICSP traces short — long PGC/PGD traces can degrade programming reliability.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified — for automotive designs, consider PIC18F27K42 automotive variants. Conflict-minerals compliant per Microchip declaration.
