PIC18F26K20-I/SS - 8-bit PIC MCU, 64KB Flash, 64MHz, SSOP-28
MPN: PIC18F26K20-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.2 | $5.20 |
| 10 | $4.85 | $48.50 |
| 100 | $4.3 | $430.00 |
| 500 | $3.8 | $1,900.00 |
| 1,000 | $3.4 | $3,400.00 |
PIC18F26K20-I/SS Overview
What is a PIC18 microcontroller? The PIC18 is Microchip's 8-bit C-optimized microcontroller family, positioned above the PIC16 line. PIC18 MCUs use a 16-bit modified Harvard architecture with separate program and data buses, 31-level hardware stack, and a RISC-like instruction set with hardware multiplier. They span the hierarchy: PIC18 -> 8-bit MCU -> microcontroller -> embedded controller. PIC18FxxK20 devices specifically target ultra-low-power applications via nanoWatt XLP technology, which adds deep-sleep modes drawing nanoamp-range currents suitable for battery-powered and energy-harvesting designs.
Key features of the PIC18F26K20 include 64 KB self-programmable Flash, 1 KB EEPROM, 3,968 bytes SRAM, 25 I/O with individual pull-up control, a 10-bit A/D converter with 14-channel input mux, two analog comparators, a 5-bit DAC, three timers (Timer0/1/2), two capture/compare modules, an Enhanced USART (EUSART) supporting RS-232/RS-485, MSSP for SPI and I2C (master/slave), and an internal 16 MHz oscillator with PLL.
From an architectural perspective, the part uses Microchip's enhanced mid-range core with a C-friendly orthogonal instruction set, hardware multiply, indexed addressing, and 31-level call/return stack. nanoWatt XLP delivers typical sleep currents below 100 nA with RTC running, allowing years of operation from a single coin cell. The device supports ICSP (In-Circuit Serial Programming) and ICD (In-Circuit Debug) via two pins, enabling fast prototyping and field firmware updates.
Typical applications include industrial sensor nodes, battery-powered data loggers, home automation controllers, low-energy IoT endpoints, HVAC control modules, consumer electronics with USB/serial connectivity, and small appliances where 25 I/O and integrated 10-bit ADC handle mixed-signal interfaces. The wide 1.8V-5.5V supply simplifies direct battery connection (1S Li-Ion, 3xAA, or coin cell with boost).
When designing, always place a 100 nF decoupling capacitor within 5 mm of each VDD pin and bulk 1-10 uF on the supply rail. Reserve MCLR with the standard 10 kohm pull-up, and add an ICSP header for programming/debug. Watch the total current budget when averaging with sleep duty cycle to maximize battery life.
Drop-in alternatives for PIC18F26K20-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 PIC18F26K20-I/SS (same form factor and footprint) — differing in Package, Timers, Program Memory (Flash), ADC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K20-I/SS
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18F26K20-I/SP
✅ Drop-In✓ In Stock
$2.94 / Unit
View Datasheet →PIC18F26K20T-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K22-I/SS
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18F46K20-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F26K20-I/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit, enhanced mid-range) |
| Program Memory (Flash) | 64 KB |
| Data Memory (RAM) | 3,968 bytes |
| EEPROM | 1,024 bytes |
| Maximum Clock Speed | 64 MHz (16 MIPS) |
| Supply Voltage (VDD) | 1.8 V to 5.5 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 14 channels |
| Comparators | 2 analog comparators |
| DAC | 5-bit |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Capture/Compare Modules | 2 (ECCP) |
| Serial Interfaces | EUSART + MSSP (SPI / I2C) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | SSOP-28 (5.30 mm body width) |
| Mounting Type | Surface Mount |
| Low-Power Technology | nanoWatt XLP |
| RoHS Status | Pb-Free / Compliant |
PIC18F26K20-I/SS Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — Digital I/O / AN0 analog input |
| Pin 3 | RA1 — Digital I/O / AN1 analog input |
| Pin 4 | RA2 — Digital I/O / AN2 analog input / VREF- |
| Pin 5 | RA3 — Digital I/O / AN3 analog input / VREF+ |
| Pin 6 | RA4 — Digital I/O / AN4 / Timer0 clock input |
| Pin 7 | VDD — Positive supply voltage |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1 — Oscillator input / CLKIN |
| Pin 10 | OSC2 — Oscillator output / CLKOUT |
| Pin 11 | RC0 — Digital I/O / SOSCO / T1CKI |
| Pin 12 | RC1 — Digital I/O / SOSCI / ECCP2 |
| Pin 13 | RC2 — Digital I/O / CCP1 |
| Pin 14 | RC3 — Digital I/O / SCL / SCK |
| Pin 15 | RC4 — Digital I/O / SDA / SDI |
| Pin 16 | RC5 — Digital I/O / SDO |
| Pin 17 | RC6 — Digital I/O / TX |
| Pin 18 | RC7 — Digital I/O / RX / DT |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0 — Digital I/O / INT0 / AN12 |
| Pin 22 | RB1 — Digital I/O / INT1 / AN10 |
| Pin 23 | RB2 — Digital I/O / INT2 / AN8 |
| Pin 24 | RB3 — Digital I/O / ECCP2 / AN9 |
| Pin 25 | RB4 — Digital I/O / AN11 |
| Pin 26 | RB5 — Digital I/O / AN13 / CCP3 |
| Pin 27 | RB6 — Digital I/O / ICSPCLK |
| Pin 28 | RB7 — Digital I/O / ICSPDAT |
Typical Applications
PIC18F26K20-I/SS is suitable for 6 applications: Industrial Sensor Nodes, Battery-Powered Data Loggers, Home Automation Controllers, HVAC Control Modules, Consumer Electronics with USB/Serial, Small Appliance Controllers.
Industrial Sensor Nodes
The PIC18F26K20-I/SS fits industrial sensor nodes thanks to its 64 KB Flash, 10-bit ADC with 14 input channels, and wide 1.8V-5.5V supply tolerance that directly accepts 24V-bus-derived rails. Its 25 I/O pins handle multiple analog and digital sensors concurrently, while nanoWatt XLP deep-sleep currents below 100 nA enable years of operation from a single 3.6 V Li-SOCl2 primary cell. The integrated EUSART and MSSP support RS-485 and I2C sensor buses without external transceivers, and the -40 C to +85 C industrial temperature range meets factory-floor requirements. The SSOP-28 package fits within 35 mm x 14 mm PCB real estate, allowing compact DIN-rail or wall-mount enclosures. EUSART DMA-free polling with hardware address recognition minimizes CPU overhead for multi-drop sensor networks.
Recommended
Battery-Powered Data Loggers
The PIC18F26K20-I/SS powers battery data loggers using nanoWatt XLP sleep currents that drop below 100 nA with RTC running. Its 1 KB EEPROM supports up to 1 million erase/write cycles per cell, ideal for event-logging without Flash wear. The 10-bit ADC quantizes analog sensor data (temperature, voltage, current) and stores results in 3,968 bytes of SRAM before batched EEPROM writes. EUSART and MSSP interfaces allow optional Bluetooth or LoRa modules for wireless data retrieval. With a 1S Li-Ion (3.7 V nominal) or 3x AA (4.5 V) supply, the wide 1.8V-5.5V range eliminates the need for additional regulators. The 64 KB Flash accommodates multi-month timestamp logic, calibration routines, and a low-power scheduling kernel.
Recommended
Home Automation Controllers
The PIC18F26K20-I/SS integrates a home automation controller's mix of analog sensors, switches, and serial peripherals onto a single IC. 25 I/O pins drive relay outputs, keypads, and indicator LEDs while the 14-channel ADC reads temperature, humidity, and light sensors through resistive bridges. EUSART connects to Wi-Fi or BLE modules for cloud gateway bridging, while MSSP (SPI or I2C) drives EEPROM storage for schedules and event logs. Flash 64 KB supports multi-protocol user interfaces (HVAC schedules, lighting scenes, security arming logic) in a C-compiled firmware image. SSOP-28 occupies modest PCB area and accepts 3.3 V regulated rails common to home automation panels. EC (error-correcting) brown-out reset and watchdog timer maintain field reliability across multi-year deployments.
Recommended
HVAC Control Modules
The PIC18F26K20-I/SS drives HVAC control modules thanks to its 25 I/O for thermostats, fan relays, and valve actuators, plus dual capture/compare modules for PWM-based motor speed control. The 10-bit ADC samples thermistor temperature sensors and current-sense amplifiers, while the two analog comparators implement zero-crossing detection for triac firing without external comparators. Operating from -40 C to +85 C, the device meets rooftop and outdoor equipment thermal envelopes. Flash 64 KB stores multi-zone scheduling, fault detection, and Modbus or BACnet protocol stacks. The wide supply range accepts 24 VAC rectified inputs via simple regulators. nanoWatt XLP standby reduces idle consumption between active control cycles.
Recommended
Consumer Electronics with USB/Serial
The PIC18F26K20-I/SS serves consumer products combining USB-to-UART bridging, button input, LED feedback, and basic analog monitoring. Although the part lacks native USB, its EUSART interfaces with CH340, CP2102, or FT232-class bridges to provide serial debug, firmware updates, and PC connectivity. 25 I/O lines drive keypads, displays (character LCD via SPI), and RGB LEDs through hardware PWM (ECCP). 64 KB Flash accommodates user-interface logic, command parsers, and protocol stacks. The SSOP-28 form factor keeps BOM cost low for high-volume consumer SKUs. nanoWatt XLP extends battery life in portable devices, while the 1.8V-5.5V VDD range supports 1S Li-Po and 2x/3x AA packs.
Recommended
Small Appliance Controllers
The PIC18F26K20-I/SS powers small appliance controllers such as coffee makers, slow cookers, washing machine user interfaces, and induction cooktops. 25 I/O drive segment displays, touch buttons via the 10-bit ADC with capacitive sensing firmware, and triac-triggered heating elements. Three timers (Timer0/1/2) implement countdown logic and PWM fan control without software overhead. Operating across -40 C to +85 C handles under-cabinet heat in appliance environments. ECCP modules generate high-resolution PWM for variable-speed motors or proportional valve control. The SSOP-28 footprint fits standard 35 mm x 30 mm appliance controller PCBs. nanoWatt XLP standby for off-mode energy savings meets ENERGY STAR idle-power criteria.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F26K20-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K20-I/SS | PIC18F26K20-I/SP | PIC18F26K20T-I/SS | PIC18F25K22-I/SS |
|---|---|---|---|---|---|
| Package | SSOP-28 | SSOP-28 (same) | PDIP-28 (through-hole, larger footprint) | SSOP-28 (same) | SSOP-28 (same) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64 KB | 32 KB | 64 KB | 64 KB | 32 KB |
| RAM | 3,968 bytes | 3,968 bytes | 3,968 bytes | 3,968 bytes | 1,536 bytes |
| EEPROM | 1,024 bytes | 1,024 bytes | 1,024 bytes | 1,024 bytes | 256 bytes |
| Max Clock Speed | 64 MHz | 64 MHz | 64 MHz | 64 MHz | 64 MHz |
| I/O Pins | 25 | 25 | 25 | 25 | 25 |
| Operating Voltage | 1.8V to 5.5V | 1.8V to 5.5V | 1.8V to 5.5V | 1.8V to 5.5V | 1.8V to 5.5V |
| ADC | 10-bit, 14 channels | 10-bit, 14 channels | 10-bit, 14 channels | 10-bit, 14 channels | 10-bit, 17 channels |
| Approx. Price (qty 1) | $5.20 | $4.50 | $5.40 | $5.20 | $4.80 |
Key Differentiators
- Maximum Flash in PIC18FxxK20 28-pin family (vs PIC18F25K20-I/SS)
- Surface-mount SSOP-28 package (vs PIC18F26K20-I/SP)
- nanoWatt XLP ultra-low-power technology (vs PIC18F25K22-I/SS)
- Same-die tape-and-reel variant for volume production (vs PIC18F26K20T-I/SS)
Design Notes
Decouple each VDD pin with a 100 nF ceramic capacitor within 5 mm of the package. Add a bulk 1-10 uF tantalum or ceramic capacitor on the supply rail near the IC. nanoWatt XLP deep-sleep current can drop below 100 nA with RTC running; ensure no high-impedance leakage paths on analog inputs (use ADC off command in idle to prevent bias current). The 1.8V-5.5V range allows direct 3x AA or 1S Li-Ion battery connection without a regulator.
The SSOP-28 package has a theta_JA of approximately 90 C/W in still air. At maximum 64 MHz clock and full peripheral activity, the device dissipates around 25-30 mA, raising junction temperature by 2-3 C above ambient. For sealed enclosures without airflow, derate clock speed or peripheral duty cycle to stay within the -40 C to +85 C industrial envelope. Estimated: assumes typical 3.3 V supply and 25 mA active current.
Place the ICSP header (5 pins: MCLR, VDD, VSS, ICSPCLK/RB6, ICSPDAT/RB7) on the PCB edge for programming access. Keep traces short to OSC1/OSC2 and avoid routing digital switching signals near analog inputs (RA0-RA5). Use a guard ring around high-impedance analog traces. The SSOP-28 0.65 mm pitch requires careful PCB routing with 0.15 mm trace width and 0.20 mm clearance.
Always include a 10 kohm pull-up on MCLR (pin 1) for proper reset operation; floating MCLR can cause spurious resets. Configure unused I/O pins as outputs low to minimize current draw. The EUSART TX/RX pins (RC6/RC7) are not 5V-tolerant when VDD is 3.3V; use level translation for RS-232 interfaces. Brown-out Reset (BOR) should be enabled to protect EEPROM from corruption at low VDD.
Compliance Information
RoHS compliant per Microchip product page; Pb-free finish. Not AEC-Q100 qualified (industrial grade only). Halogen-free per Microchip packaging specifications.
