PIC18LF27K42-I/SS - 128KB Flash 8-bit MCU XLP | Microchip
MPN: PIC18LF27K42-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.79 | $279.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.15 | $2,150.00 |
PIC18LF27K42-I/SS Overview
What is a low-power 8-bit microcontroller? An MCU (microcontroller unit) is a single-chip computer integrating CPU core, Flash program memory, SRAM data memory, EEPROM, and configurable peripherals. The PIC18 family uses an enhanced Harvard architecture with a RISC-style instruction set, and the XLP (eXtreme Low Power) designation marks devices engineered for sub-uA sleep currents and fast wake-up times. Within Microchip's taxonomy, the K42 series adds Core Independent Peripherals (CIPs) such as CLC, NCO, and PWM that operate without CPU intervention, easing real-time firmware development.
Key features include the 64MHz internal oscillator, 12-bit differential ADC2 with computation, multiple communication interfaces (UART, SPI, I2C), and 25 I/O pins. The "LF" prefix indicates a wide VDD range of 1.8V to 3.6V optimized for battery operation, while the "F" variants run from 2.3V to 5.5V. The 128KB Flash (64K x 16) supports self-programming and large protocol stacks, and the 28-SSOP (0.209 inch, 5.30mm width) is a narrow-body surface-mount footprint compatible with standard hand-soldering and reflow profiles.
The PIC18LF27K42 architecture pairs the enhanced mid-range core with vectored interrupts, a hardware multiplier/divider, and DMA channels that move data between peripherals and RAM without CPU cycles. CIP blocks (CLC, NCO, PWM, ADC-with-computation) enable deterministic peripheral chains that run independently of the CPU, allowing the core to sleep for the majority of the duty cycle and wake only on interrupt events.
Typical applications include battery-powered IoT sensor nodes, wearable fitness/medical devices, low-power wireless sensor hubs, mixed-signal instrumentation, and small home appliances. The wide VDD range and low sleep current also suit remote controls, electronic shelf labels, and energy-harvesting designs where quiescent draw dominates battery life.
When designing with this device, plan to leverage the DMA + CIP combination to keep the CPU in sleep mode as long as possible, and budget the 1KB EEPROM carefully for write-cycle endurance. Verify the 28-SSOP pinout against your board layout - the SSOP is 5.30mm wide with 0.65mm pitch and is the same footprint used by the F-variant.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the standalone manufacturer datasheet - specifically the side-by-side parametric comparison, the FA-{D} automotive qualifier note, and the SSOP-vs-SO footprint tradeoff guidance.
Drop-in alternatives for PIC18LF27K42-I/SS — 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/SS (same form factor and footprint) — differing in Package, ADC, Operating Temperature, DAC, Comparators.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F27K42-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF27K40-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF27K40-I/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18LF26K42-I/SS
✅ Drop-In✓ In Stock
$2.02 / Unit
View Datasheet →PIC18LF26K40-I/SS
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC18LF26K22-I/SS
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18LF27K42-I/SS Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit enhanced mid-range |
| Family | PIC® XLP™ 18K |
| Series | PIC18(L)FxxK42 |
| Program Memory (Flash) | 128 KB (64K x 16) |
| Data RAM | 8 KB |
| Data EEPROM | 1 KB |
| Maximum CPU Frequency | 64 MHz |
| Supply Voltage (VDD) | 1.8 V to 3.6 V |
| Operating Temperature | -40C to +85C (Industrial) |
| I/O Pins | 25 |
| ADC | 12-bit ADC2 with computation |
| DAC | Yes (5-bit / 8-bit) |
| Comparators | Yes |
| DMA Channels | Yes (hardware DMA) |
| Vector Interrupts | Yes |
| PWM Channels | Yes (multiple channels) |
| UART | Yes |
| SPI | Yes |
| I2C | Yes |
| Core Independent Peripherals (CIP) | CLC, NCO, PWM with computation, DMA |
| Package | 28-SSOP (0.209 inch, 5.30 mm width) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC18LF27K42-I/SS Pin Configuration
| Pin 1 | RA5 — Port A bit 5 / general-purpose I/O |
| Pin 2 | RA4 — Port A bit 4 / general-purpose I/O |
| Pin 3 | RA3 — Port A bit 3 / general-purpose I/O |
| Pin 4 | RA2 — Port A bit 2 / general-purpose I/O |
| Pin 5 | RA1 — Port A bit 1 / general-purpose I/O / DAC1OUT |
| Pin 6 | RA0 — Port A bit 0 / general-purpose I/O |
| Pin 7 | VDD — Positive supply voltage (1.8V-3.6V) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7 — Port A bit 7 / general-purpose I/O |
| Pin 10 | RA6 — Port A bit 6 / general-purpose I/O |
| Pin 11 | RC0 — Port C bit 0 / general-purpose I/O |
| Pin 12 | RC1 — Port C bit 1 / general-purpose I/O |
| Pin 13 | RC2 — Port C bit 2 / general-purpose I/O |
| Pin 14 | RC3 — Port C bit 3 / general-purpose I/O / SCL |
| Pin 15 | RC4 — Port C bit 4 / general-purpose I/O / SDA |
| Pin 16 | RC5 — Port C bit 5 / general-purpose I/O |
| Pin 17 | RC6 — Port C bit 6 / general-purpose I/O / TX |
| Pin 18 | RC7 — Port C bit 7 / general-purpose I/O / RX |
| Pin 19 | VSS — Ground reference (second) |
| Pin 20 | VDD — Positive supply voltage (1.8V-3.6V) (second) |
| Pin 21 | RB0 — Port B bit 0 / general-purpose I/O / INT0 |
| Pin 22 | RB1 — Port B bit 1 / general-purpose I/O / INT1 |
| Pin 23 | RB2 — Port B bit 2 / general-purpose I/O |
| Pin 24 | RB3 — Port B bit 3 / general-purpose I/O |
| Pin 25 | RB4 — Port B bit 4 / general-purpose I/O |
| Pin 26 | RB5 — Port B bit 5 / general-purpose I/O |
| Pin 27 | RB6 — Port B bit 6 / general-purpose I/O / ICSPCLK |
| Pin 28 | RB7 — Port B bit 7 / general-purpose I/O / ICSPDAT |
Typical Applications
PIC18LF27K42-I/SS is suitable for 6 applications: Battery-Powered IoT Sensor Nodes, Wearable Fitness/Health Devices, Low-Power Wireless Sensor Hubs, Mixed-Signal Instrumentation, Home Appliance Control Boards, Remote Controls / Electronic Shelf Labels.
Battery-Powered IoT Sensor Nodes
The PIC18LF27K42-I/SS suits IoT sensor hubs that spend >99% of the time in sleep. Its 1.8V-3.6V VDD range allows direct connection to a single Li-ion or 2xAA cell, while 128KB Flash stores protocol stacks (LoRaWAN, BLE host, MQTT-SN). The DMA + ADC2-with-computation chain digitizes a sensor and triggers a wake event without CPU intervention. Combined with XLP sleep currents below 1 uA, a single CR2032 can power periodic telemetry nodes for years. The 64MHz CPU wakes in microseconds and executes the stack before returning to sleep.
Recommended
Wearable Fitness/Health Devices
Wearable fitness bands require a tiny MCU with long battery life, modest Flash for BLE profiles, and accurate analog front-ends. The PIC18LF27K42-I/SS delivers 128KB Flash for BLE stacks or proprietary RF protocols, plus a 12-bit ADC2 that captures optical heart-rate sensor outputs with hardware averaging. Its DMA offloads sensor reads from the CPU, and the integrated comparators and op-amp cores drive photodiode front-ends. The 28-SSOP package fits narrow wristband PCBs and reflows at standard 245C profiles. Voltage tolerance down to 1.8V lets designs run directly from Li-PO without an LDO.
Recommended
Low-Power Wireless Sensor Hubs
A wireless hub aggregates multiple sensor nodes via sub-GHz or 2.4GHz radios and forwards data to a gateway. The PIC18LF27K42-I/SS acts as the hub controller: its UART/SPI ports drive transceivers (MRF89XA, AT86RF233), and the DMA engine moves packet payloads into RAM without CPU cycles. The 8KB RAM is sufficient for buffering multi-node telemetry. Hardware AES and CIPs can run packet authentication in the background. The wide VDD and 1.8V minimum allow direct connection to harvested-energy storage cells with voltage margin for cold-start scenarios.
Recommended
Mixed-Signal Instrumentation
Bench instruments such as handheld multimeters and lab data loggers need precise ADCs, generous Flash for calibration tables, and low quiescent current for battery operation. The PIC18LF27K42-I/SS integrates a 12-bit ADC2 with hardware averaging and oversampling, plus 128KB Flash to store linearization coefficients and UI strings. The 8KB RAM supports waveform buffers, and the comparators implement threshold detection. The on-chip DAC drives reference or stimulus outputs. Its 28-SSOP form factor is easy to hand-prototype, and the 64MHz CPU executes real-time DSP filters at audio bandwidth.
Recommended
Home Appliance Control Boards
Small home appliances (coffee machines, blenders, robotic vacuums) need a low-cost MCU with motor-control PWMs, sensor interfaces, and reliable Flash for user-interface firmware. The PIC18LF27K42-I/SS provides multi-channel PWM with computation for brushless-DC or stepper control, DMA-driven sensor acquisition, and 128KB Flash for UI menus and over-the-air update slots. The LF voltage range suits 3.3V-only appliances that need to drop down to 1.8V for sleep. SSOP package is widely accepted by EMS lines and supports hand rework.
Recommended
Remote Controls / Electronic Shelf Labels
Remotes and ESL displays are coin-cell powered, deeply duty-cycled, and update only on button press or RF poll. The PIC18LF27K42-I/SS sleep current under 1 uA extends CR2032 life to multi-year horizons. Its 12-bit ADC2 reads battery voltage for fuel gauging, and the CLCs generate wake-on-button logic without CPU intervention. With 128KB Flash, designers can store multi-protocol IR/RF code tables or bitmap data. The 28-SSOP is small enough to fit behind a coin-cell holder. Designers should budget EEPROM write cycles for ESL image updates.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF27K42-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F27K42-I/SS | PIC18LF26K42-I/SS | PIC18LF27K40-I/SS |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SSOP | 28-SSOP - same | 28-SSOP - same | 28-SSOP - same |
| Flash Memory | 128 KB | 128 KB | 64 KB (-50%) | 32 KB (-75%) |
| RAM | 8 KB | 8 KB | 8 KB | 2 KB (-75%) |
| EEPROM | 1 KB | 1 KB | 1 KB | 256 B (-75%) |
| Max CPU Clock | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| VDD Range | 1.8V to 3.6V | 2.3V to 5.5V | 1.8V to 3.6V | 1.8V to 3.6V |
| DMA / CIP | Yes (DMA, CLC, NCO) | Yes | Yes | Yes |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- 128 KB Flash with DMA and full CIP set (vs PIC18LF27K40-I/SS)
- Low-voltage LF variant (1.8V-3.6V) (vs PIC18F27K42-I/SS)
- CIP-rich K42 architecture with hardware AES-ready DMA (vs PIC18LF26K22-I/SS)
Design Notes
Estimated: at 64 MHz CPU active and all peripherals enabled, the PIC18LF27K42-I/SS draws roughly 8-10 mA from a 3.3V rail. In Sleep mode with no peripherals active, current drops to ~50 nA typical (per XLP datasheet target). For battery designs, plan the duty cycle so that active time is dominated by sensor I/O rather than CPU cycles - the DMA + ADC2-with-computation combination can run sensor chains while the CPU sleeps. Always measure sleep current on the actual board; leakage through I/O pull-ups can dominate if not disabled.
Place decoupling capacitors (100 nF + 10 uF bulk) within 5 mm of each VDD pin (pins 7 and 20). The 28-SSOP package has only 0.65 mm pitch - use reflow soldering rather than hand-soldering for production. Keep the ICSP pins (RB6/RB7, pins 27-28) accessible for in-circuit programming. Both VSS pins (8 and 19) must be connected to a ground plane for thermal and EMI performance; star-ground the analog AVSS separately if precision ADC results are required.
Do not confuse the PIC18LF27K42 with the PIC18LF27K40 - the K40 has only 32KB Flash / 2KB RAM and lacks several CIPs. Verify the exact ordering code (PIC18LF27K42-I/SS) before programming; the silicon ID differs. Also watch the VDD range: the LF variant does NOT operate reliably above 3.6V - for 5V rails use the F variant (PIC18F27K42-I/SS). On first power-up, configure the Configuration Words (CONFIG1L through CONFIG5L) before any code execution, or the device may latch in an unintended oscillator mode.
Compliance Information
RoHS/REACH compliant per Microchip product page. Not AEC-Q100 qualified - choose PIC18F27K42-I/SO automotive variant for AEC-Q100 use.
