PIC18LF26K40T-I/ML - 64KB Flash 8-bit MCU, 28-QFN | Microchip
MPN: PIC18LF26K40T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.42 | $2.42 |
| 10 | $2.18 | $21.80 |
| 100 | $1.95 | $195.00 |
| 500 | $1.74 | $870.00 |
| 1,000 | $1.55 | $1,550.00 |
| 3,300 | $1.39 | $4,587.00 |
PIC18LF26K40T-I/ML Overview
A microcontroller (MCU) is a compact integrated circuit containing a CPU core, program memory (Flash), data memory (RAM/EEPROM), and programmable peripherals on one die. The PIC18 family sits in the 8-bit MCU hierarchy, between simple PIC10/PIC12 baseline parts and higher-pin-count PIC24/PIC32 16/32-bit parts. The 'LF' prefix indicates the wide-voltage variant (1.8 V to 3.6 V operation), distinguishing it from the 'F' 2.3 V-5.5 V siblings, while the 'XLP' (eXtreme Low Power) label denotes sub-uA/MHz active current and multiple deep-sleep modes with peripheral wake.
Key features include 64 KB self-programmable Flash, 4 KB SRAM, 256 B EEPROM, a 10-bit ADC with Computation (ADC2), 5-bit DAC, comparators with selectable rail-to-rail inputs, 8-bit/16-bit timers, PWM, CCP, CWG, SMT, WWDT with windowed mode, ZCD, and Peripheral Pin Select for flexible I/O mapping. CWG and ZCD together enable zero-cross switching for TRIAC/SCR dimmers. The 28-QFN (6x6) package is footprint-compatible with the 28-pin SPDIP/SOIC variants.
The LF core combines a 16-bit wide instruction path with a 31-level hardware stack and a modified Harvard bus, giving the part its 64 MIPS throughput at 64 MHz while keeping deterministic interrupt latency. ADC2 (Computation ADC) adds averaging, oversampling and threshold comparison in hardware, offloading the CPU in sensor and touch applications.
Typical applications include LED lighting and TRIAC dimmer control, IoT sensor nodes, low-power consumer appliances, USB-CDC/HID human-interface devices, motor-control BLDC/H-bridge drivers, and battery-powered metering. The wide 1.8 V-3.6 V supply range and XLP nanoWatt XLP sleep modes (<1 uA typical with RTC) suit 2xAA and coin-cell designs.
Design with this part requires attention to VDDCORE decoupling (the LF K40 needs a 1 uF + 100 nF pair on the dedicated core pin), proper MCLR pull-up for in-circuit serial programming (ICSP), and ICP/ICD pin assignment via #pragma to keep PGx/PGx free in production. The internal 32 kHz LFINTOSC plus PLLx4 enable low-Iq operation without an external crystal.
This page consolidates distributor pricing, drop-in alternative MPNs, application guidance and design notes not found on a single distributor listing.
Drop-in alternatives for PIC18LF26K40T-I/ML — 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 PIC18LF26K40T-I/ML (same form factor and footprint) — differing in ADC, Communication, Comparators, Core, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF26K40T-E/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF26K40-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F26K40T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF26K42T-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF26K40T-I/MV
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18LF26K40T-I/ML Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit |
| Program Memory (Flash) | 64 KB (32K x 16) |
| SRAM | 4 KB |
| EEPROM | 256 B |
| Maximum CPU Speed | 64 MHz (16 MIPS per MHz dependent on family; 64 MHz system clock) |
| Supply Voltage (Vdd) | 1.8 V to 3.6 V |
| I/O Pins | Up to 25 |
| ADC | 10-bit ADC2 (Computation ADC) |
| DAC | 5-bit DAC |
| Comparators | Yes (rail-to-rail inputs) |
| Timers | 8-bit and 16-bit, SMT |
| PWM Modules | PWM, CCP, CWG (Complementary Waveform Generator) |
| Communication | UART, I2C, SPI, EUSART |
| Operating Temperature | -40C to +85C (Industrial, 'I' suffix) |
| Package | 28-pin QFN (ML), 6 x 6 mm |
| Mounting Type | Surface Mount |
| MSL Level | 3 |
| RoHS Status | Compliant |
| Peripherals | WWDT, CRC/Memory Scan, ZCD, Peripheral Pin Select, Hardware CVD |
| Low-Power Feature | XLP (nanoWatt XLP): sub-uA deep sleep with RTC |
PIC18LF26K40T-I/ML Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O / analog / CCP3 |
| Pin 2 | RA3 — Bidirectional I/O / analog |
| Pin 3 | RA4 — Bidirectional I/O / analog / T0CKI |
| Pin 4 | RA5 — Bidirectional I/O / analog / interrupt-on-change |
| Pin 5 | RA6 — Bidirectional I/O / oscillator |
| Pin 6 | RA7 — Bidirectional I/O / oscillator |
| Pin 7 | VSS — Ground reference |
| Pin 8 | VDD — Positive supply (1.8 V to 3.6 V) |
| Pin 9 | RA0 — Bidirectional I/O / analog / ICSPDAT |
| Pin 10 | RA1 — Bidirectional I/O / analog / ICSPCLK |
| Pin 11 | RB0 — Bidirectional I/O / interrupt-on-change / ZCD |
| Pin 12 | RB1 — Bidirectional I/O / interrupt-on-change |
| Pin 13 | RB2 — Bidirectional I/O / interrupt-on-change |
| Pin 14 | RB3 — Bidirectional I/O / interrupt-on-change |
| Pin 15 | RB4 — Bidirectional I/O / interrupt-on-change / SDA |
| Pin 16 | RB5 — Bidirectional I/O / interrupt-on-change / SCL |
| Pin 17 | RB6 — Bidirectional I/O / PGC (ICSP clock) |
| Pin 18 | RB7 — Bidirectional I/O / PGD (ICSP data) |
| Pin 19 | MCLR — Master Clear / reset input (active low) |
| Pin 20 | RC0 — Bidirectional I/O / analog / PWM/CWG |
| Pin 21 | RC1 — Bidirectional I/O / analog / PWM/CWG |
| Pin 22 | RC2 — Bidirectional I/O / analog / PWM |
| Pin 23 | RC3 — Bidirectional I/O / analog / SCL1 |
| Pin 24 | RC4 — Bidirectional I/O / analog / SDA1 |
| Pin 25 | RC5 — Bidirectional I/O / analog |
| Pin 26 | RC6 — Bidirectional I/O / TX/CK |
| Pin 27 | RC7 — Bidirectional I/O / RX/DT |
| Pin 28 | VSS — Ground reference (second VSS on QFN) |
| Pin EP | EP — Exposed thermal pad - connect to VSS for thermal dissipation |
Typical Applications
PIC18LF26K40T-I/ML is suitable for 6 applications: AC Mains TRIAC Dimmer and LED Lighting, Low-Power IoT Sensor Node (2xAA / Coin Cell), USB HID Human Interface Devices (Keyboard / Mouse / Custom HID), BLDC / H-Bridge Motor Control for Small Fans and Pumps, Battery-Powered Smart Meter and Utility Monitoring, Consumer Appliance Control and HMI (Washers / Coffee Machines / Ovens).
AC Mains TRIAC Dimmer and LED Lighting
The PIC18LF26K40T-I/ML fits AC mains TRIAC dimmer and LED lighting because its integrated Zero-Cross Detect (ZCD) peripheral synchronizes switching to the AC line and the Complementary Waveform Generator (CWG) provides dead-band-controlled complementary outputs for half-bridge LED drivers. With 64 KB Flash, the part can host DALI-2 or 0-10 V dimming firmware plus power-factor-correction state machines without external memory. The 1.8 V-3.6 V wide supply supports both single-cell and 3.3 V buck topologies, while XLP nanoWatt sleep (<1 uA) keeps standby consumption well below 100 mW - a regulatory must in EU Ecodesign. The 28-QFN (6x6) footprint leaves room for the triac-driver optocoupler and zero-cross sensing resistors on a compact lamp PCB. Compared to discrete dimmer ICs, this K40 part adds OTA firmware update over UART for tunable white-balance curves.
Recommended
Low-Power IoT Sensor Node (2xAA / Coin Cell)
For battery-powered IoT sensor nodes, the PIC18LF26K40T-I/ML offers 1.8 V-3.6 V operation that lets a 2xAA stack discharge to ~2.0 V before brown-out, and XLP nanoWatt sleep modes reduce quiescent current to under 1 uA with the RTCC running. The 64 KB Flash accommodates over-the-air (OTA) bootloader plus BLE/Zigbee application code, while the 10-bit ADC2 with hardware averaging offloads sensor sampling from the CPU. The 28-QFN (ML) 6x6 mm package is well-suited to compact sensor PCBAs inside IP65 enclosures. Its 25 I/O lines drive SPI sensors, I2C peripherals and a low-power UART bridge, and the integrated WWDT with windowed mode meets IEC 60730 functional-safety requirements for unattended household appliances. The same die as PIC18LF26K40-I/SS allows PCB reuse across THT and SMT variants.
Recommended
USB HID Human Interface Devices (Keyboard / Mouse / Custom HID)
The PIC18LF26K40T-I/ML serves as a USB HID device controller when paired with a USB-to-UART bridge such as the MCP2200, using its EUSART for command handling and ADC2 for analog key-matrix or capacitive-touch scanning. While the LF26K40 itself has no native USB, the wide 1.8 V-3.6 V supply is ideal for a low-power tethered mouse or presenter, and the 64 KB Flash fits full HID descriptor stacks plus vendor-specific report protocols. The 28-QFN (6x6) keeps the PCB small enough for slim keyboard PCBs. The integrated CWG and PWM channels enable LED backlight control and side-lit indicator animations, while the ZCD peripheral simplifies AC-line-powered presentation remotes. For full-speed USB natively, step up to PIC18F27J53 (28-QFN); otherwise, this LF26K40 plus a bridge IC gives cost-effective HID functionality.
Recommended
BLDC / H-Bridge Motor Control for Small Fans and Pumps
For BLDC and H-bridge motor control in small fans, pumps and 12 V actuators, the PIC18LF26K40T-I/ML delivers 16-bit PWM plus the Complementary Waveform Generator with programmable dead-band, which is essential for safely driving N-channel MOSFET half-bridges. Its 64 MHz system clock and 10-bit ADC2 with hardware triggering allow field-oriented control (FOC) loops inside the 64 KB Flash budget. The 28-QFN (6x6 mm) package fits on compact driver boards; 25 I/O lines connect to Hall sensors, back-EMF amplifiers and fault inputs. Wide 1.8 V-3.6 V supply supports both 3.3 V logic-level and 5 V gate-drive FETs when an LDO is added. The K40 CIPs (CWG, ZCD, SMT, PWM) offload switching control from the CPU, leaving headroom for higher-order torque-control firmware.
Recommended
Battery-Powered Smart Meter and Utility Monitoring
The PIC18LF26K40T-I/ML is well-suited to battery-powered smart meters and utility monitoring devices thanks to its 10-bit ADC2 with Computation (oversampling and averaging) that delivers 14-bit effective resolution for current/voltage sensing, plus 256 B of EEPROM for non-volatile tariff and calibration data retention. Its 1.8 V-3.6 V operation lets a single-cell LiSOCl2 battery drive the meter for 10+ years with XLP sleep current below 1 uA. The 64 KB Flash accommodates DLMS/COSEM or Modbus firmware stacks, and the 28-QFN (ML) package supports miniaturized, potted metering PCBs. CRC/Scan hardware protects Flash integrity per IEC 62056-21, and the WWDT with windowed mode helps meet IEC 60730 Class B functional-safety requirements. ZCD simplifies AC-zero timing in single-phase energy meters.
Recommended
Consumer Appliance Control and HMI (Washers / Coffee Machines / Ovens)
The PIC18LF26K40T-I/ML drives consumer appliance control and HMI boards, replacing multiple 8/16-bit timer ICs with one Core Independent Peripheral rich device. Its PWM, CCP and CWG outputs control triac-driven heater elements and motor relays, while the 10-bit ADC2 reads NTC thermistors and water-level sensors. The 5-bit DAC plus comparators form a closed-loop safety cutoff independent of CPU activity - a key IEC 60730 functional-safety requirement. With 64 KB Flash and 4 KB RAM, the part fits full graphic-segment LCD driving via software plus capacitive touch via the ADC2 CTMU mode. The industrial -40 to +85 C rating survives inside appliance enclosures; the 28-QFN (6x6) keeps the mainboard compact. The 'E' temperature variant PIC18LF26K40T-E/ML extends this to +125 C for oven interiors.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF26K40T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF26K40T-E/ML | PIC18LF26K40-I/ML | PIC18F26K40T-I/ML | PIC18LF26K42T-I/ML | PIC18LF26K40T-I/MV |
|---|---|---|---|---|---|---|
| Package | 28-QFN (ML, 6x6) | 28-QFN (ML, 6x6) - same | 28-QFN (ML, 6x6) - same | 28-QFN (ML, 6x6) - same | 28-QFN (ML, 6x6) - same | 28-UDFN (MV, 4x4) - smaller land pattern |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Program Memory (Flash) | 64 KB | 64 KB - same | 64 KB - same | 64 KB - same | 64 KB - same | 64 KB - same |
| SRAM | 4 KB | 4 KB - same | 4 KB - same | 4 KB - same | 4 KB - same | 4 KB - same |
| EEPROM | 256 B | 256 B - same | 256 B - same | 256 B - same | 256 B - same | 256 B - same |
| Supply Voltage | 1.8 V to 3.6 V | 1.8 V to 3.6 V - same | 1.8 V to 3.6 V - same | 2.3 V to 5.5 V | 1.8 V to 3.6 V - same | 1.8 V to 3.6 V - same |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C - same | -40C to +85C - same | -40C to +85C - same | -40C to +85C - same |
| CPU Clock (max) | 64 MHz | 64 MHz - same | 64 MHz - same | 64 MHz - same | 64 MHz - same | 64 MHz - same |
| Core Independent Peripherals (CIPs) | CWG, ZCD, ADC2, WWDT, CRC, PPS, CLC, SMT | Same CIPs - identical | Same CIPs - identical | Same CIPs - identical | Same + more CLC and 8-bit DAC | Same CIPs - identical |
| Pricing (1pc, approx., as of 2026-09-28) | $2.42 | $2.55 - higher due to extended grade | $2.42 - same, tube carrier | $2.42 - same | $2.65 - newer die | $2.50 - smaller UDFN package |
Key Differentiators
- Industry-leading Core Independent Peripherals (CIPs) integration in 28-QFN (vs PIC18F46K22)
- Wide 1.8 V-3.6 V supply supports deeper battery discharge (vs PIC18F26K40T-I/ML)
- Sub-uA deep-sleep XLP current with full RAM retention and RTCC (vs PIC18F27J53)
- Extended industrial temperature -40 C to +125 C option in same package (vs PIC18LF26K40T-I/ML (industrial grade))
Design Notes
The PIC18LF26K40T-I/ML requires two separate supply pins: VDD (1.8 V-3.6 V) and VDDCORE (internally regulated to 1.8 V). A 100 nF decoupling capacitor must be placed within 1-2 mm of each VDD/VSS pin pair, and a dedicated 1 uF + 100 nF pair is mandatory on the VDDCORE pin per Microchip's K40 hardware checklist. Failure to provide these decoupling capacitors results in oscillator start-up failures or ADC inaccuracies at the LF end of the supply range. Place the bulk 1 uF ceramic (X7R, 10 V rating) on the same PCB layer, with a via-to-ground plane connection no longer than 2 mm trace. Estimated: assuming 50 mA peak transient from Core + ADC2, the 100 nF cap must have ESR < 50 milliohm to limit VDD ripple below 30 mV.
For 28-QFN (ML) 6x6 mm layout, the exposed thermal pad (EP) must be soldered to a VSS-connected copper pour of at least 25 mm^2 (roughly a 5x5 mm pattern) to meet thermal resistance of theta_JA ~ 35 C/W. The pad array is 0.4 mm pitch with a central 4.0 mm thermal pad; place 9 thermal vias (0.3 mm drill, 0.5 mm pad) in a 3x3 grid under the EP to conduct heat to an inner VSS plane. All QFN signal pads should be routed out on the top layer with the EP keep-out ring respected; do not route signals under the IC body. In-circuit serial programming (ICSP) requires PGx/PGx pins (RB6/RB7) accessible via test pads if MCLR/ICSPDAT/ICSPCLK are shared with RA1/RA0 in the application.
Common design pitfalls with PIC18LF26K40T-I/ML: (1) Confusing 'LF' (1.8 V-3.6 V) with 'F' (2.3 V-5.5 V) - applying 5 V to the LF part causes permanent damage; verify the full ordering code. (2) Forgetting the MCLR pull-up resistor (typically 10 kohm to VDD) - leaving MCLR floating causes intermittent resets. (3) Disabling the BOR (Brown-Out Reset) in CONFIG - this is mandatory for LF operation below 2.0 V to avoid code execution in invalid voltage ranges. (4) Not configuring PPS (Peripheral Pin Select) unlock sequence before assigning remappable functions - the unlock registers IOCON/PPSLOCK must be toggled per the datasheet. (5) Using HFINTOSC at full 64 MHz without setting the PLL postscaler - some K40 firmware defaults leave the PLL off. Always run the 'MCU PIC18F26K40 Family Configuration' tool in MPLAB X Code Configurator.
The PIC18LF26K40T-I/ML industrial (-40 C to +85 C) and extended (-40 C to +125 C for the 'E' variant) temperature grades share the same 28-QFN package thermal resistance. In QFN packages the dominant heat path is via the exposed thermal pad to the PCB copper pour, so a 5x5 mm VSS pour with 9 thermal vias gives theta_JA ~ 35 C/W (estimated based on JEDEC EIA/JESD51 standards for 28-QFN 6x6 mm with 9-via thermal pad). At 25 mA active current (typical for 64 MHz operation including CIPs), self-heating is roughly 45 mW, yielding ~1.6 C rise - well within derating. However, in closed industrial enclosures the ambient can approach +70 C, leaving only ~15 C margin to the +85 C junction limit; consider the 'E' variant for hot environments.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified; the 'F' variant in automotive ordering code PIC18F26K40-E/SP (not -I/ML) would be the automotive-grade option. Industrial temperature grade ('I') spans -40 to +85 C; for +125 C use 'E' (extended) variant.
