PIC18LF27K40-I/SO - 64MHz 128KB Flash 8-bit XLP MCU | Microchip
MPN: PIC18LF27K40-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.95 | $3.95 |
| 10 | $3.61 | $36.10 |
| 100 | $3.2 | $320.00 |
| 500 | $2.84 | $1,420.00 |
| 1,000 | $2.55 | $2,550.00 |
PIC18LF27K40-I/SO Overview
What is a low-power 8-bit microcontroller? A low-power 8-bit microcontroller is a single-chip computer that combines a CPU, non-volatile program memory, working RAM, data EEPROM, and multiple analog/digital peripherals on one die, optimized for minimal energy consumption. The PIC18LF27K40 belongs to the hierarchy: microcontroller -> 8-bit MCU -> PIC18 family -> XLP low-power subfamily -> 28-pin SOIC class. XLP technology adds deep-sleep modes with peripheral wake-up, enabling years of operation from a single coin cell in metering or remote-sensor designs.
Key features include 128 KB self-programmable Flash with high endurance, hardware CRC and SCAN for functional safety, a 10-bit ADC with automated acquisition and threshold comparison, multiple communications peripherals (UART/SPI/I2C), and up to 25 I/O pins with interrupt-on-change capability. The 5-bit DAC and 3 op-amps eliminate the need for external analog components in many sensor-interface designs, reducing BOM cost and PCB area while improving noise immunity.
Typical applications include battery-powered IoT sensor nodes, low-power wireless HMI panels, industrial process controllers, and portable medical monitors. The wide peripheral integration supports digital power conversion, motor control via PWM/CWG, and safety-critical signal monitoring using WWDT and ZCD.
When designing with this part, verify the Vdd range: the LF variant tops out at 3.6 V, so a 5 V rail must use the F-suffix. Add a 0.1 uF decoupling capacitor within 5 mm of each power pin and follow Microchip AN1252 for low-power PCB layout. The integrated CIP peripherals let you replace several discrete components with deterministic hardware state machines.
Drop-in alternatives for PIC18LF27K40-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 PIC18LF27K40-I/SO (same form factor and footprint) — differing in Package, ADC, Operating Temperature, DAC, PWM Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F27K40-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F27K40-E/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF27K40-E/SO
✅ Drop-In✓ In Stock
$1.86 / Unit
View Datasheet →PIC18F26K40-I/SO
✅ Drop-In✓ In Stock
$1.41 / Unit
View Datasheet →PIC18LF26K40-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F26K42-I/SO
✅ Drop-In✓ In Stock
$1.43 / Unit
View Datasheet →PIC18LF25K40-I/SO
✅ Drop-In✓ In Stock
$1.65 / Unit
View Datasheet →PIC18LF27K40-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| CPU Architecture | Enhanced Mid-Range PIC18 |
| Maximum Clock Speed | 64 MHz |
| Program Memory (Flash) | 128 KB (64K x 16) |
| RAM | 4 KB |
| EEPROM | 256 bytes |
| Operating Voltage Range | 1.8 V to 3.6 V (LF variant) |
| I/O Pins | 25 |
| ADC | 10-bit ADC2 with Computation |
| DAC | 5-bit |
| Comparators | Yes |
| Op-Amps | 3 (integrated) |
| PWM Channels | Multiple (PWM/CCP/CWG) |
| Package | SOIC-28 (300 mil) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| Low-Power Technology | XLP (eXtreme Low Power) |
| RoHS Status | Compliant |
PIC18LF27K40-I/SO Pin Configuration
| Pin 1 | RA3/AN3/VREF+/CMP1IN0+ — Digital I/O / analog input / voltage reference / comparator input |
| Pin 2 | RA2/AN2/CMP1IN0- — Digital I/O / analog input / comparator input |
| Pin 3 | RA1/AN1/CMP1IN1-/CMP2IN0- — Digital I/O / analog input / comparator input |
| Pin 4 | RA0/AN0/CMP1IN3+/CMP2IN0+ — Digital I/O / analog input / comparator input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RA7/OSC1/CLKIN — Digital I/O / crystal oscillator input / external clock input |
| Pin 7 | RA6/OSC2/CLKOUT — Digital I/O / crystal oscillator output / clock output |
| Pin 8 | RB0/ZCD/C1IN0+ — Digital I/O / zero-cross detect / comparator input |
| Pin 9 | RB1/OPA1IN+ — Digital I/O / op-amp 1 non-inverting input |
| Pin 10 | RB2/OPA1IN- — Digital I/O / op-amp 1 inverting input |
| Pin 11 | RB3/OPA1OUT — Digital I/O / op-amp 1 output |
| Pin 12 | RB4/OPA2IN+ — Digital I/O / op-amp 2 non-inverting input |
| Pin 13 | RB5/OPA2IN- — Digital I/O / op-amp 2 inverting input |
| Pin 14 | RB6/OPA2OUT/PGC — Digital I/O / op-amp 2 output / ICSP clock |
| Pin 15 | RB7/ICSPDAT — Digital I/O / ICSP data |
| Pin 16 | VDD — Positive power supply |
| Pin 17 | VSS — Ground reference |
| Pin 18 | RC7/RX/DT — Digital I/O / EUSART RX / EUSART data |
| Pin 19 | RC6/TX/CK — Digital I/O / EUSART TX / EUSART clock |
| Pin 20 | RC5 — Digital I/O |
| Pin 21 | RC4 — Digital I/O |
| Pin 22 | RC3/SCL/SCK — Digital I/O / I2C clock / SPI clock |
| Pin 23 | RC2/SDA/SDI — Digital I/O / I2C data / SPI data in |
| Pin 24 | RC1/SDO — Digital I/O / SPI data out |
| Pin 25 | RC0/SS — Digital I/O / SPI slave select |
| Pin 26 | RA5 — Digital I/O |
| Pin 27 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Pin 28 | MCLR/VPP — Master clear reset / programming voltage |
Typical Applications
PIC18LF27K40-I/SO is suitable for 7 applications: Battery-Powered IoT Sensor Nodes, Industrial Process Controllers, Portable Medical Monitors, Low-Power Wireless HMI Panels, Digital Power and Motor Control, Automotive Body and Lighting Modules, Smart Home Sensor Hubs.
Battery-Powered IoT Sensor Nodes
The PIC18LF27K40-I/SO is well matched to battery-powered IoT sensor nodes because its XLP sleep current drops below 50 nA with RAM retention and its 1.8 to 3.6 V range accepts a single lithium or 2x AA cell stack directly. The 10-bit ADC with computation performs oversampling and threshold detection without CPU wake-up, while the integrated 5-bit DAC and 3 op-amps condition thermocouple or strain-gauge signals without external components. With 128 KB Flash, the part holds LoRaWAN class-A stacks or BLE HCI firmware plus application code, eliminating the need for an external memory. A typical design places the MCU in sleep with RTCC running, wakes every few seconds to take an ADC reading, transmits via a sub-GHz or BLE module, and returns to sleep, achieving multi-year coin-cell life.
Recommended
Industrial Process Controllers
For industrial process controllers the PIC18LF27K40-I/SO provides 128 KB Flash for ladder-logic interpreters or PID control firmware, plus hardware CRC and SCAN peripherals that support functional-safety verification of program flow. The 10-bit ADC with computation offloads filtering and threshold checks, while the CWG, PWM, and CCP peripherals drive triac-controlled heater circuits or proportional valves. The -40C to +85C industrial temperature range tolerates factory-floor enclosures, and the 28-pin SOIC footprint is well-suited to DIN-rail-mounted PCBs. The MCU's deterministic interrupt latency from Core Independent Peripherals makes it appropriate for closed-loop control loops in the millisecond range.
Recommended
Portable Medical Monitors
The PIC18LF27K40-I/SO suits portable medical monitors such as pulse oximeters, glucose meters, and ambulatory ECG patches where low-power operation and integrated analog peripherals are critical. Its 3 internal op-amps drive the photodiode transimpedance front-end of a pulse oximeter, while the 10-bit ADC with computation performs SpO2 averaging in hardware. The XLP architecture permits intermittent sampling with sub-microamp sleep current, supporting patient-worn designs powered by a single CR2032. With 128 KB Flash, the device stores Bluetooth Low Energy protocol stacks for transmitting vitals to a smartphone, plus patient-record buffers in its 4 KB RAM. The 28-pin SOIC package is small enough to fit on a wrist-strap PCB.
Recommended
Low-Power Wireless HMI Panels
Handheld wireless HMI panels used for industrial remote control benefit from the PIC18LF27K40-I/SO's combination of XLP sleep modes and rich CIP peripheral mix. The 128 KB Flash holds menu firmware, button-debounce state machines, and wireless protocol stacks without external memory. Multiple PWM channels drive vibration motors for haptic feedback, while the integrated comparators wake the part instantly when a button is pressed. The 1.8 to 3.6 V range accepts a single Li-ion cell directly, eliminating boost converters and improving efficiency. The 28-pin SOIC package fits behind a small TFT LCD in a pocket-sized enclosure.
Recommended
Digital Power and Motor Control
The PIC18LF27K40-I/SO is suitable for digital power conversion and low-power motor control thanks to its CWG (Complementary Waveform Generator), CCP, and PWM peripherals that produce dead-band-controlled complementary outputs for MOSFET driving. The high-speed 10-bit ADC samples inductor current and output voltage synchronously to the PWM cycle for peak-current-mode control, while the integrated op-amp conditions current-sense signals without external components. ZCD detects AC line zero-cross for TRIAC dimming or PFC. With 128 KB Flash, the MCU holds state-space or PID control firmware for DC-DC, BLDC, or PFC stages in single-stage designs.
Recommended
Automotive Body and Lighting Modules
Although the -I/SO suffix denotes industrial temperature, the PIC18LF27K40-I/SO architecture is also leveraged in non-safety automotive body and lighting subsystems such as ambient LED controllers, mirror adjusters, and HVAC actuators. The CWG peripheral generates complementary PWM with dead-band control for driving high-side and low-side LED FETs, while the integrated op-amps condition analog sensor signals. The 128 KB Flash supports LIN protocol stacks plus application logic, allowing direct communication with body controllers without a companion transceiver IC. The 28-pin SOIC package fits behind dashboard panels and within door modules where board height is constrained.
Recommended
Smart Home Sensor Hubs
For smart-home sensor hubs such as wireless door/window sensors, leak detectors, and air-quality monitors, the PIC18LF27K40-I/SO provides the right balance of low sleep current, generous Flash, and analog integration. The integrated op-amp directly drives a metal-oxide gas sensor or photo-diode, while the 10-bit ADC with hardware averaging samples signals without CPU intervention. The ZCD peripheral detects AC mains zero-cross in plug-in energy monitors, and the comparator wakes the MCU from sleep on threshold crossings. With 128 KB Flash, the MCU holds Zigbee or Matter commissioning logic plus application firmware, eliminating external EEPROM and reducing BOM cost.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF27K40-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F27K40-I/SO | PIC18F27K40-E/SO | PIC18LF27K40-E/SO | PIC18F26K40-I/SO | PIC18LF26K40-I/SO | PIC18F26K42-I/SO | PIC18LF25K40-I/SO |
|---|---|---|---|---|---|---|---|---|
| Package | SOIC-28 (300 mil) | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same | SOIC-28 (300 mil) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB | 64 KB | 64 KB | 64 KB | 32 KB |
| RAM | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 2 KB |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 1 KB | 1 KB | 1 KB | 256 bytes |
| Operating Voltage | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 1.8 V to 3.6 V |
| Max CPU Speed | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| Temperature Range | -40C to +85C | -40C to +85C | -40C to +125C | -40C to +125C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| 1-Piece Price (USD) | 3.95 | 3.65 | 4.10 | 4.25 | 3.35 | 3.55 | 3.20 | 2.95 |
Key Differentiators
- Largest Flash density in the 28-pin LF K40 family (vs PIC18LF26K40-I/SO)
- Low-voltage operation supports 1.8 V coin-cell designs (vs PIC18F27K40-I/SO)
- Triple integrated op-amps eliminate external analog front-end (vs PIC18LF25K40-I/SO)
Design Notes
Place a 0.1 uF decoupling capacitor within 5 mm of pins 16 (VDD) and 17 (VSS). Add a 10 uF bulk capacitor at the supply rail entry point. The PIC18LF27K40-I/SO's Vdd core draws up to 3 mA at 64 MHz, so the bulk cap must supply instantaneous current during ADC conversions and PWM transitions. For battery-powered designs, an MCP1700 LDO is recommended because its 1.6 uA quiescent current complements the MCU's sub-50 nA sleep current, preserving overall system efficiency.
Route the ICSP clock and data signals (RB6/PGC, RB7/PGD) away from high-current switching nodes and analog op-amp inputs to avoid programming and runtime noise coupling. The SOIC-28 footprint has 1.27 mm pitch - keep analog guard traces grounded on both sides of sensitive op-amp and ADC traces. Place the 32.768 kHz crystal close to OSC1/OSC2 if RTCC accuracy matters, with short traces and ground flood to minimize stray capacitance.
Do not exceed 3.6 V on Vdd - the LF suffix is the low-voltage variant and will be damaged by 5 V rails. For multi-rail designs, use the F-suffix part instead. Configure the PPS (Peripheral Pin Select) registers before enabling peripherals; otherwise, pins will float and may source/sink unintended current. Finally, when using XLP sleep modes, verify that all unused peripherals are explicitly disabled in firmware - a single active peripheral can multiply sleep current by orders of magnitude.
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial temperature grade only; not AEC-Q100 qualified. For AEC-Q100 automotive applications use the PIC18F27K40-E/SO (extended temp) but verify with Microchip's automotive product list.
