PIC18F26K20-I/ML - 64KB Flash 8-Bit MCU, 64MHz, 28-QFN | Microchip
MPN: PIC18F26K20-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.51 | $3.51 |
| 10 | $3.18 | $31.80 |
| 100 | $2.74 | $274.00 |
| 500 | $2.31 | $1,155.00 |
| 1,000 | $1.96 | $1,960.00 |
PIC18F26K20-I/ML Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and a rich set of peripherals such as ADC, timers, communication interfaces, and general-purpose I/O. Within the broader semiconductor taxonomy, an MCU belongs to the embedded processor category, which sits below microprocessors and above basic digital logic ICs. PIC18F microcontrollers use a modified Harvard RISC architecture with a 16-bit instruction word optimized for C code density, and the 'K20' sub-family adds nanoWatt XLP technology to dramatically reduce active and sleep power compared to legacy PIC18 parts.
Key features include a 10-bit ADC with up to 11 input channels, two analog comparators, a hardware USART, MSSP for SPI and I2C (both Master and Slave), two CCP modules and one enhanced CCP for PWM and capture/compare, four 8-bit timers plus three 16-bit timers, and 25 mA capable I/O suitable for direct LED drive. The internal oscillator block provides factory-calibrated 16 MHz and selectable frequencies up to 64 MHz via the 4x PLL, often eliminating the need for an external crystal in cost-sensitive designs.
The -I/ML part is specified for 1.8V to 3.6V core operation and 4.2V to 5.5V extended-range operation, and supports ICSP (In-Circuit Serial Programming) plus optional low-voltage programming. The QFN-28 package offers a small 6x6 mm footprint with an exposed thermal pad, ideal for space-constrained PCB layouts. Self-programmability under firmware control and Microchip's free MPLAB X IDE + XC8 toolchain enable field-upgradeable end products.
Typical applications include low-power wireless sensor nodes, battery-powered HVAC thermostats, portable medical monitors, USB HID human-interface devices, white-goods motor control, and remote controls. The combination of nanoWatt XLP sleep current and rich peripherals allows designers to meet multi-year battery-life targets while still driving user interfaces and analog sensors.
When designing with this device, leave at least 4 mm2 of copper under the QFN exposed pad tied to VSS for thermal relief and reliable reflow. Place a 100 nF decoupling capacitor within 3 mm of each power pin, and reserve the ICSP/ICD pins (PGC/PGD, MCLR) for in-circuit programming access. To preserve the ultra-low sleep current of ~20 nA, ensure unused I/O pins are configured as outputs or tied to VDD/VSS through software, never left floating.
This page consolidates Microchip datasheet specifications, current distributor pricing tiers, same-package drop-in alternatives, and practical PCB design notes into a single reference so you can evaluate the PIC18F26K20-I/ML without leaving the page.
Drop-in alternatives for PIC18F26K20-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 PIC18F26K20-I/ML (same form factor and footprint) — differing in Core Architecture, Package, ADC, Analog Comparators, Capture/Compare/PWM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K20-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F26K20-E/ML
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →PIC18F26K22-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K22-I/ML
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.74 / Unit
View Datasheet →PIC18F25K40-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F25K50-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F26K20-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 8-bit RISC (modified Harvard) |
| Program Flash | 64 KB |
| RAM | 3,968 bytes |
| EEPROM | 1,024 bytes |
| Maximum CPU Clock | 64 MHz (16 MIPS) |
| Supply Voltage (Core) | 1.8 V to 3.6 V |
| Supply Voltage (Extended) | 4.2 V to 5.5 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 11 channels |
| Timers | 4 x 8-bit + 3 x 16-bit |
| Capture/Compare/PWM | 2 CCP + 1 ECCP |
| Communication | 1 x USART (EUSART), 1 x MSSP (SPI/I2C) |
| Analog Comparators | 2 |
| Internal Oscillator | 31 kHz to 16 MHz with 4x PLL |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | QFN-28 (6x6 mm) with exposed thermal pad |
| Mounting Type | Surface Mount |
| MSL Level | 3 |
| RoHS Status | Compliant |
| Lead-Free / Halogen-Free | Yes / Yes |
PIC18F26K20-I/ML Pin Configuration
| Pin 1 | RA2 — Digital I/O / analog input AN2 / CVREF |
| Pin 2 | RA3 — Digital I/O / analog input AN3 / VREF+ |
| Pin 3 | RA4 — Digital I/O / analog input AN4 / Timer0 clock |
| Pin 4 | RA5 — Digital I/O / analog input AN5 / Timer1 clock |
| Pin 5 | RA6 — Digital I/O / oscillator pin |
| Pin 6 | RA7 — Digital I/O / oscillator pin |
| Pin 7 | VSS — Ground reference |
| Pin 8 | VDD — Positive supply voltage |
| Pin 9 | RB0 — Digital I/O / interrupt-on-change / AN10 |
| Pin 10 | RB1 — Digital I/O / interrupt-on-change / AN8 |
| Pin 11 | RB2 — Digital I/O / interrupt-on-change |
| Pin 12 | RB3 — Digital I/O / interrupt-on-change / PGM |
| Pin 13 | RB4 — Digital I/O / interrupt-on-change |
| Pin 14 | RB5 — Digital I/O / interrupt-on-change / PGC |
| Pin 15 | RB6 — Digital I/O / interrupt-on-change / PGD |
| Pin 16 | RB7 — Digital I/O / interrupt-on-change |
| Pin 17 | RC0 — Digital I/O / SOSCO |
| Pin 18 | RC1 — Digital I/O / SOSCI / CCP2 |
| Pin 19 | RC2 — Digital I/O / CCP1 / AN11 |
| Pin 20 | RC3 — Digital I/O / SCL / AN7 |
| Pin 21 | RC4 — Digital I/O / SDA |
| Pin 22 | RC5 — Digital I/O / SDO |
| Pin 23 | RC6 — Digital I/O / TX |
| Pin 24 | RC7 — Digital I/O / RX / DT |
| Pin 25 | MCLR — Master clear / reset input (active low) |
| Pin 26 | RA0 — Digital I/O / analog input AN0 |
| Pin 27 | RA1 — Digital I/O / analog input AN1 |
| Pin 28 | VSS — Ground reference (thermal pad recommended) |
Typical Applications
PIC18F26K20-I/ML is suitable for 6 applications: Battery-Powered Wireless Sensor Nodes, HVAC Thermostats and Building Controls, Portable Medical Monitoring Devices, Industrial Sensor and Process Transmitters, USB HID Human-Interface Devices, White-Goods Motor and Appliance Control.
Battery-Powered Wireless Sensor Nodes
The PIC18F26K20-I/ML is well matched to wireless sensor nodes because its nanoWatt XLP sleep current of ~20 nA typical lets the MCU spend most of its life in sleep between sensor reads and radio transmissions. The 64 KB Flash comfortably holds an IEEE 802.15.4 or sub-GHz protocol stack plus application code, while the 3,968 bytes of RAM is sufficient for sensor buffers and link-layer queues. The internal 16 MHz oscillator (4x PLL to 64 MHz) eliminates an external crystal, reducing BOM cost and quiescent draw. Pairing with a sub-GHz transceiver such as Microchip's MRF89XA yields a battery life measured in years on a single coin cell, ideal for environmental and building-automation telemetry.
Recommended
HVAC Thermostats and Building Controls
In HVAC thermostats, the PIC18F26K20-I/ML provides the analog and digital peripherals required to read temperature, humidity, and user input while driving a triac-controlled HVAC load. Its 10-bit ADC with 11 channels handles NTC thermistor dividers and rotary encoder inputs; the 2 CCP + 1 ECCP block can generate zero-cross synchronized PWM for triac firing. The 25 mA I/O directly drives LED indicators and a character LCD, while USART and MSSP interfaces communicate with Wi-Fi or BLE modules for cloud connectivity. Industrial -40 C to +85 C temperature grade and robust ESD performance allow direct deployment in equipment rooms and on-wall enclosures.
Recommended
Portable Medical Monitoring Devices
Portable medical devices such as pulse oximeters, glucose meters, and portable ECG monitors benefit from the PIC18F26K20-I/ML's combination of low active power, integrated 10-bit ADC for sensor front-ends, and ample Flash for trend logging. The 64 KB program memory supports USB HID or CDC stacks for direct PC interface, while 3,968 bytes of RAM holds short-term waveforms and rolling averages. XLP sleep current extends battery life between measurements, critical for chronic-disease management devices prescribed for daily use. The 28-QFN 6x6 mm footprint fits comfortably in handheld plastic enclosures.
Recommended
Industrial Sensor and Process Transmitters
Industrial 4-20 mA loop-powered transmitters use the PIC18F26K20-I/ML to digitize sensor signals, perform linearization, and modulate the loop current. The 10-bit ADC is sufficient for pressure, flow, and level sensors; the MSSP supports SPI sensor ICs while the USART supports digital panel-meter output. Industrial temperature grade plus the MCU's robust analog performance allow deployment in -40 C factory environments without additional shielding. The 64 KB Flash reserves room for custom linearization tables, Modbus RTU stacks, and future firmware updates via ICSP.
Recommended
USB HID Human-Interface Devices
USB Human Interface Devices such as keyboards, mice, custom keypads, and game controllers can be implemented on the PIC18F26K20-I/ML using the MSSP for USB bit-banging plus 64 KB Flash to host the HID descriptor and protocol stack. The 25 mA I/O directly drives LED indicators and key-scanning matrices without external drivers, while the hardware USART and CCP modules can support additional features like capacitive-touch sliders and rotary encoders. Operating from a single 5 V USB rail simplifies power architecture, and ICSP allows field firmware updates without opening the enclosure.
Recommended
White-Goods Motor and Appliance Control
Washing machines, dishwashers, and small kitchen appliances use the PIC18F26K20-I/ML to control BLDC, universal, or shaded-pole motors via the ECCP PWM output and dedicated timer channels. The 2 analog comparators implement current-limit and zero-cross detection, while the 10-bit ADC monitors motor current and supply voltage. The industrial -40 C to +85 C temperature grade plus robust ESD allow placement near power electronics, and 64 KB Flash reserves space for proprietary motor-control algorithms and user-interface state machines.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F26K20-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K20-I/ML | PIC18F26K20-E/ML | PIC18F26K22-I/ML | PIC18F25K22-I/ML | PIC18F25K40-I/ML | PIC18F25K50-I/ML |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | QFN-28 (ML) 6x6 | QFN-28 (ML) 6x6 - same | QFN-28 (ML) 6x6 - same | QFN-28 (ML) 6x6 - same | QFN-28 (ML) 6x6 - same | QFN-28 (ML) 6x6 - same | QFN-28 (ML) 6x6 - same |
| Program Flash | 64 KB | 32 KB | 64 KB | 64 KB | 32 KB | 32 KB | 32 KB |
| Maximum Clock | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 48 MHz |
| I/O Pins | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| Temperature Grade | Industrial -40C to +85C | Industrial -40C to +85C | Extended -40C to +125C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C |
| On-Chip USB | No (bit-bang only) | No | No | No | No | No | Yes (USB 2.0 FS) |
| XLP nanoWatt Sleep | Yes (~20 nA typical) | Yes | Yes | Yes | Yes | Yes | Yes |
| ADC Channels | 11 (10-bit) | 11 | 11 | 11 | 11 | 11 | 11 |
Key Differentiators
- Largest Flash in the 28-QFN K20 family (vs PIC18F25K20-I/ML)
- Extended temperature option available (vs PIC18F26K20-E/ML)
- Newer K22 family upgrade path with full component repoversy (vs PIC18F26K22-I/ML)
- Optional on-chip USB peripheral in K50 family (vs PIC18F25K50-I/ML)
Design Notes
The 28-QFN (ML) package has an exposed thermal pad that MUST be soldered to a copper pour tied to VSS to meet the datasheet's thermal resistance specification and to ensure reliable reflow. Recommended: at least 4 mm2 of continuous copper under the pad, with thermal vias to internal ground layers for high-power or sealed-enclosure designs.
Place a 100 nF decoupling capacitor within 3 mm of every VDD pin and a bulk capacitor (1-10 uF) at the regulator output. To preserve the XLP sleep current (~20 nA typical), configure unused I/O as outputs or tie them to VDD/VSS in firmware, never leave floating, and disable unused peripherals in firmware before entering sleep.
Reserve PGC/PGD (RB5/RB6) and MCLR pins for ICSP access; pulling them up with 10 kohm and isolating them from heavy-load drivers prevents programming failures. The internal oscillator's factory calibration is only accurate to within a few percent; for asynchronous serial or USB bit-banging, tune OSCTUNE per application note or use an external crystal.
Route the analog (RA/AN) traces away from switching nodes and the triac/MOSFET drive traces; place the AGND island as a star-ground tied to VSS at one point only. Keep analog traces short and shield them with a ground pour on the layer below to minimize ADC noise pickup at low sensor signal levels.
For I2C operation above 400 kHz, add 4.7 kohm pull-ups on SCL/SDA and series resistors near the MCU pin to suppress ringing. For SPI at high speeds, route CLK and MOSI/MISO as a matched-length group and avoid running them parallel to noise sources for more than a few millimeters.
Compliance Information
RoHS and lead-free confirmed per Microchip product page and DigiKey listing; AEC-Q100 not applicable for industrial-grade -I parts; automotive-grade version is the PIC18F26K20-E/ML extended temperature variant.
