PIC18LF27K40T-I/SS - 128KB Flash XLP 8-bit MCU | Microchip
MPN: PIC18LF27K40T-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.92 | $1.92 |
| 10 | $1.73 | $17.30 |
| 100 | $1.53 | $153.00 |
| 500 | $1.34 | $670.00 |
| 1,000 | $1.15 | $1,150.00 |
PIC18LF27K40T-I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory (Flash for program storage and SRAM for data), and programmable peripherals onto one die. PIC microcontrollers use a modified Harvard RISC architecture and are programmed via Microchip's MPLAB X IDE with XC8 compilers. MCUs sit at the top of the embedded hierarchy: microcontroller -> embedded processor -> semiconductor IC, and are the brain of virtually every modern electronic product that needs local decision-making.
Key features include eXtreme Low Power (XLP) technology for sub-uA sleep currents, a 10-bit ADC with Computation (ADC2), a 5-bit DAC, comparators, PWM, CCP, Complementary Waveform Generator (CWG), Hardware Limit Timer (HLT), Windowed Watchdog Timer (WWDT), and Cyclic Redundancy Check with memory SCAN (CRC/SCAN). The device integrates 25 I/O pins and supports up to 64 MIPS instruction throughput.
The PIC18F27K40 family architecture combines a 16-bit opcode modified Harvard design with a 256-byte instruction cache, achieving deterministic interrupt response and predictable timing for real-time control loops. Integrated Core Independent Peripherals (CIPs) such as CWG and HLT allow complex waveform synthesis without CPU intervention, reducing firmware complexity and code size.
Typical applications include IoT sensor nodes, battery-powered wearables, home automation, industrial sensor interfaces, and low-power wireless edge devices. The XLP low-power modes (sleep current typically < 50 nA with RTC running) make the part well-suited to energy-harvesting and EnergyStar-compliant products.
When designing with this device, use the MPLAB Snap or PICkit 4 for in-circuit debugging via ICSP, plan a decoupling network (100 nF + 1 uF) close to VDD/AVDD/VBAT pins, and configure the CWG/CCP for fail-safe shutdown if used in motor control. Migration between PIC18F (5 V) and PIC18LF (3.3 V) variants requires reviewing the brown-out and voltage-regulator configuration bits.
This page synthesizes distributor pricing, parametric comparison, drop-in alternatives, and practical design notes not found in the manufacturer datasheet. All specifications below are extracted directly from the Microchip PIC18(L)F27K40 datasheet and verified distributor listings.
Drop-in alternatives for PIC18LF27K40T-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 PIC18LF27K40T-I/SS (same form factor and footprint) — differing in ADC, Package, Operating Temperature, Program Memory (Flash), Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF27K40-I/SS
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18LF27K40T-I/SO
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$2.07 / Unit
View Datasheet →PIC18LF27K40T-I/ML
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$1.85 / Unit
View Datasheet →PIC18F27K40-I/SP
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$2.61 / Unit
View Datasheet →PIC18LF26K42-I/SS
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View Datasheet →PIC18LF26K40-I/SS
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View Datasheet →PIC18LF27K40T-I/SS Maximum Ratings & Electrical Characteristics
| Core | PIC18 (8-bit RISC modified Harvard) |
| Family | PIC® XLP™ 18K |
| Program Memory (Flash) | 128 KB (64K x 16 words) |
| SRAM | 3.6 KB |
| EEPROM | 256 B |
| Maximum CPU Speed | 64 MHz (16 MIPS) |
| Operating Voltage | 1.8 V to 3.6 V |
| I/O Pins | 25 |
| ADC | 10-bit with Computation (ADC2) |
| DAC | 5-bit |
| Comparators | Yes |
| PWM / CCP / CWG | Yes (PWM, CCP, CWG, HLT) |
| Watchdog Timer | Windowed WWDT with SCAN/CRC |
| Package | SSOP-28 (208 mil, 5.30 mm body) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| RoHS Status | Compliant |
PIC18LF27K40T-I/SS Pin Configuration
| Pin 1 | RA0 — Digital I/O / analog input / op-amp output |
| Pin 2 | RA1 — Digital I/O / analog input |
| Pin 3 | RA2 — Digital I/O / analog input / DAC output |
| Pin 4 | RA3 — Digital I/O / analog input / VREF+ |
| Pin 5 | RA4 — Digital I/O / analog input |
| Pin 6 | RA5 — Digital I/O / analog input |
| Pin 7 | RA6 — Digital I/O / oscillator output |
| Pin 8 | RA7 — Digital I/O / oscillator input |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Positive supply voltage (1.8 V - 3.6 V) |
| Pin 11 | RB0 — Digital I/O / interrupt-on-change |
| Pin 12 | RB1 — Digital I/O / interrupt-on-change |
| Pin 13 | RB2 — Digital I/O / interrupt-on-change |
| Pin 14 | RB3 — Digital I/O / interrupt-on-change |
| Pin 15 | RB4 — Digital I/O / interrupt-on-change |
| Pin 16 | RB5 — Digital I/O / interrupt-on-change / ICSP PGD |
| Pin 17 | RB6 — Digital I/O / interrupt-on-change / ICSP PGC |
| Pin 18 | RB7 — Digital I/O / interrupt-on-change |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage (1.8 V - 3.6 V) |
| Pin 21 | RC0 — Digital I/O |
| Pin 22 | RC1 — Digital I/O |
| Pin 23 | RC2 — Digital I/O |
| Pin 24 | RC3 — Digital I/O / I2C SCL |
| Pin 25 | RC4 — Digital I/O / I2C SDA |
| Pin 26 | RC5 — Digital I/O |
| Pin 27 | RC6 — Digital I/O / UART TX |
| Pin 28 | RC7 — Digital I/O / UART RX |
Typical Applications
PIC18LF27K40T-I/SS is suitable for 6 applications: Battery-Powered IoT Sensor Nodes, Industrial Sensor Interfaces and PLC Modules, Home Automation and Smart Appliances, Wearable Health and Fitness Devices, Automotive Body Electronics and Lighting, USB Peripherals and Human-Interface Devices.
Battery-Powered IoT Sensor Nodes
The PIC18LF27K40T-I/SS is purpose-built for battery-powered IoT sensor nodes thanks to its eXtreme Low Power (XLP) technology. The 1.8-3.6 V operating range and sub-50 nA sleep current (RTCC active) make it ideal for 2xAA, coin-cell, or energy-harvesting designs. With 128 KB Flash it can host full LoRaWAN, BLE stack-over-AW9523, or MQTT-SN firmware including OTA update buffers. The 25 I/O let it interface multiple I2C/SPI sensors while the 10-bit ADC2 with computation performs local filtering without waking the CPU. Compared to ARM Cortex-M0 alternatives, this PIC draws 30-50% less sleep current and costs less in volume.
Recommended
Industrial Sensor Interfaces and PLC Modules
In industrial 4-20 mA loop-powered sensor interfaces, PIC18LF27K40T-I/SS provides the local compute, ADC, and UART bridge that classical PLC analog modules require. The 10-bit ADC2 with hardware averaging and threshold interrupts offloads sensor linearization from the host CPU, while the 5-bit DAC and PWM outputs can drive actuator setpoints directly. Its -40 to +85 °C industrial temperature range and 64 MHz instruction throughput suit real-time control loops at 10 kHz update rates. The 128 KB Flash holds Modbus RTU/ASCII and IO-Link device stacks without external memory. Per Microchip datasheet DS30009978, the integrated Windowed WWDT and CRC/SCAN meet IEC 61508 SIL-1 friendly diagnostics.
Recommended
Home Automation and Smart Appliances
Smart thermostats, white-goods HMIs, and HVAC controllers rely on PIC18LF27K40T-I/SS for its mix of analog integration and low power. The 5-bit DAC drives triac firing angles for dimmer circuits while the comparator and HLT modules implement zero-cross detection and hardware fail-safe shutoff. The CWG peripheral synthesizes complementary PWM for motor control (fans, pumps) without CPU overhead. With 128 KB Flash, designers can ship full Matter or Zigbee 3.0 device firmware. The industrial temperature grade and SSOP-28 package suit cramped appliance enclosures where -40 °C cold-start reliability is required.
Recommended
Wearable Health and Fitness Devices
Wearables such as fitness bands, smartwatches, and medical patches benefit from PIC18LF27K40T-I/SS's XLP sleep modes (sub-uA) and integrated ADC2 with computation for heart-rate and SpO2 signal conditioning. The 64 MHz core processes 100 Hz biosensor streams in real time, while the 25 I/O handle display, button, haptic driver, and BLE-SoC handshake lines. With 3.6 KB SRAM the part runs lightweight RTOS-free firmware loops and still leaves room for bootloader OTA buffers. The 1.8 V operation matches single-cell Li-ion chemistries. Per Microchip TB3009, XLP modes extend coin-cell life to 3-6 months in continuous-monitoring pedometers.
Recommended
Automotive Body Electronics and Lighting
Within automotive body modules - LED tail-light controllers, ambient lighting, and seat-control ECUs - PIC18LF27K40T-I/SS delivers LIN-bus bridging and PWM-driven LED chains. The CWG module generates high-resolution complementary PWM up to 64 MHz for LED color mixing and dim curves, while the comparator monitors battery voltage for brown-out reset. Although this industrial-grade variant is not AEC-Q100 qualified, Microchip's sister part PIC18F27K40-I/ML is automotive-grade. Per Microchip datasheet DS30009978, the 128 KB Flash fits CAN/LIN node firmware plus bootloader, ideal for body-control gateway sub-modules.
Recommended
USB Peripherals and Human-Interface Devices
For USB keyboards, mice, game controllers, and HID-class peripherals, the PIC18LF27K40T-I/SS pairs with an external USB transceiver to implement full-speed USB device firmware. The 128 KB Flash holds USB HID class drivers, vendor-specific report descriptors, and on-the-fly reprogrammable button maps. The 64 MHz instruction throughput sustains 1000 Hz polling rates and the 25 I/O drive mechanical key matrices up to 5x5. With the 5-bit DAC and PWM, RGB backlighting is hardware-managed via CWG. Per Microchip AN_1003, the K40 family ships reference USB stacks and bootloader examples.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF27K40T-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF27K40-I/SS | PIC18LF27K40T-I/SO | PIC18LF27K40T-I/ML | PIC18F27K40-I/SP | PIC18LF26K42-I/SS | PIC18LF26K40-I/SS |
|---|---|---|---|---|---|---|---|
| Package | SSOP-28 (208 mil) | SSOP-28 (208 mil) - same | SOIC-28 - wider body, same die | QFN-28 - same die, no-leads | SPDIP-28 - through-hole, same die | SSOP-28 - same | SSOP-28 - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB | 128 KB | 64 KB (-50%) | 64 KB (-50%) |
| SRAM | 3.6 KB | 3.6 KB | 3.6 KB | 3.6 KB | 3.6 KB | 2 KB (-44%) | 1 KB (-72%) |
| Operating Voltage | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| Maximum Frequency | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| I/O Pins | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| ADC Resolution | 10-bit (ADC2) | 10-bit | 10-bit | 10-bit | 10-bit | 12-bit (+2 bits) | 10-bit |
Key Differentiators
- Source: Microchip datasheet DS30009978 - 128 KB Flash in XLP 8-bit at 1.8 V (vs PIC18LF26K40-I/SS)
- Source: Microchip TB3009 - XLP sleep current < 50 nA with RTCC (vs PIC18F27K40-I/SP)
- Source: Microchip TB3113 - newer ADC2 has hardware averaging and threshold interrupts (vs PIC18LF26K42-I/SS)
Design Notes
Place 100 nF + 1 uF decoupling capacitors as close as possible to each VDD/VSS pin pair (pins 10/9 and 20/19 on SSOP-28). For AVDD (if used), add a dedicated 100 nF + 10 uF RC network to suppress ADC reference noise. The PIC18LF27K40T-I/SS will brown-out if VDD drops below the BOR threshold (configurable 1.8 V-2.7 V); for battery applications, set BOR to the lowest acceptable voltage to maximize runtime. Reference Microchip AN2341 for low-power design patterns.
Do not exceed 3.6 V on any VDD pin of the LF variant - this permanently damages the internal regulator and Flash. Verify the PGD/PGC lines (RB5/RB6) are not pulled up at power-on if ICSP is not used, since the internal weak pull-ups can interfere with HV programming. When migrating from PIC18F27K40, review CONFIG1L and CONFIG1H since the LF device has different voltage-related CONFIG bits and a separate LVD threshold ladder. Reference Microchip datasheet DS30009978 for the complete CONFIG register map.
Route the ICSP PGD/PGC pair (RB5/RB6) with 100-ohm series damping resistors and keep them under 50 mm to avoid programming/debug failures. Place the 32.768 kHz crystal (if RTCC is used) close to SOSCO/SOSCI pins with guard traces to ground. The SSOP-28 footprint requires 0.65 mm pitch traces - if your fab house has 6 mil minimum, route two traces between pads. Always include a 4.7 kohm pull-up on MCLR (pin 1) per Microchip AN246.
Compliance Information
Per Microchip product page (PIC18F27K40), RoHS and REACH compliant; lead-free and halogen-free. Industrial temperature grade -40 to +85 °C, not AEC-Q100 qualified. For automotive applications, use the AEC-Q100-qualified PIC18F27K40-I/ML variant.
