PIC18F26K20-I/SO - 8-Bit 64MHz MCU 64KB Flash | Microchip
MPN: PIC18F26K20-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.93 | $2.93 |
| 10 | $2.66 | $26.60 |
| 100 | $2.3 | $230.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.78 | $1,780.00 |
PIC18F26K20-I/SO Overview
What is an 8-bit microcontroller? An 8-bit MCU is a single-chip computer whose CPU processes data 8 bits at a time, typically using a Harvard or modified-Harvard architecture with separate program and data memory buses. The PIC18 family is a high-performance 8-bit family within the broader PIC microcontroller hierarchy (PIC10/12/16/18), positioned above baseline PIC16 parts and below the 16-bit dsPIC and 32-bit SAM families. The PIC18F26K20 specifically targets ultra-low-power applications where extended battery life matters more than raw MIPS.
Key features include active current as low as several hundred microamps at 1MHz, deep sleep current down to the nanoamp range, an internal 16MHz oscillator with PLL support, and a wide 1.8V to 5.5V supply range (the -I industrial variant operates over -40C to +85C). The 64KB Flash supports self-programming via ICSP, and the device is supported by Microchip's MPLAB X IDE and XC8 compiler toolchain, which includes the free XC8 compiler version for hobby and commercial development.
From an architectural standpoint, the PIC18F26K20 uses a modified Harvard architecture with a 16-bit instruction word and 8-bit data path, providing a good balance of code density and execution speed. The nanoWatt XLP technology adds sleep modes such as deep sleep, ultra-low-power watchdog timer, and multiple oscillator options to minimize current draw in battery-powered applications.
Typical applications include portable medical instruments, remote sensor nodes, industrial control modules, automotive body electronics (non-safety), home automation, USB-to-UART bridges, and low-power IoT edge devices. The 28-SOIC package provides an easy-to-handle footprint for hand-prototyping and rework while still being suitable for high-volume surface-mount assembly.
When designing with this device, ensure the supply voltage is decoupled with at least 100nF ceramic placed close to the VDD pins, and add a 10uF bulk capacitor on the main rail. For low-power designs, leverage the deep-sleep mode and disable unused peripherals through the peripheral disable registers to minimize quiescent current.
This page synthesizes distributor pricing, drop-in compatible alternatives in the SOIC-28 footprint, and practical low-power design notes not found in the standalone datasheet, giving engineers a single reference for selection and procurement decisions.
Drop-in alternatives for PIC18F26K20-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 PIC18F26K20-I/SO (same form factor and footprint) — differing in Program Memory (Flash), ADC, Package, RoHS Status, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F26K20-E/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F26K20-I/SP
✅ Drop-In✓ In Stock
$2.94 / Unit
View Datasheet →PIC18F26K22-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K20-I/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18F26J13-I/SO
✅ Drop-In✓ In Stock
$2.25 / Unit
View Datasheet →PIC18F2620-I/SO
✅ Drop-In✓ In Stock
$5.21 / Unit
View Datasheet →PIC18F26K20-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit) |
| CPU Speed (Maximum) | 64 MHz (16 MIPS) |
| Program Memory (Flash) | 64 KB |
| SRAM | 3936 bytes |
| EEPROM | 256 bytes |
| Operating Voltage Range | 1.8 V to 3.6 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 17 channels |
| Timers | 8-bit and 16-bit timer modules |
| CCP/ECCP Modules | 2 CCP / 1 ECCP |
| USART | 2 |
| MSSP (SPI / I2C) | 1 |
| Comparators | 2 analog comparators |
| Package | 28-pin SOIC (SO), wide-body |
| Operating Temperature | -40C to +85C (industrial) |
| Technology | nanoWatt XLP (eXtreme Low Power) |
| ICSP / ICD Support | Yes (In-Circuit Serial Programming / Debug) |
| RoHS Status | Compliant (Pb-free) |
| Mounting Type | Surface Mount |
PIC18F26K20-I/SO Pin Configuration
| Pin 1 | MCLR/VPP/RE3 — Master Clear (reset) input / programming voltage / digital input only on PORTE bit 3 |
| Pin 2 | RA0/AN0/CVREF — PORTA bit 0 / analog input channel 0 / comparator voltage reference output |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / analog input channel 2 / ADC negative voltage reference |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input channel 3 / ADC positive voltage reference |
| Pin 6 | RA4/AN4/T0CKI/C1OUT — PORTA bit 4 / analog input channel 4 / Timer0 clock input / comparator 1 output |
| Pin 7 | RA5/AN5/SS/HLVDIN/C2OUT — PORTA bit 5 / analog input channel 5 / SPI slave select / high/low voltage detect input / comparator 2 output |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKI/RA7 — External oscillator input / clock input / PORTA bit 7 |
| Pin 10 | OSC2/CLKO/RA6 — External oscillator output / clock output / PORTA bit 6 |
| Pin 11 | RC0/T1OSO/T13CKI — PORTC bit 0 / Timer1 oscillator output / Timer1/Timer3 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / Capture-Compare-PWM 2 |
| Pin 13 | RC2/CCP1/P1A — PORTC bit 2 / Capture-Compare-PWM 1 / PWM output 1A |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock (MSSP) |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data input / I2C data (MSSP) |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data output (MSSP) |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART asynchronous transmit / USART synchronous clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART asynchronous receive / USART synchronous data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0/AN12/INT0/FLT0 — PORTB bit 0 / analog input channel 12 / external interrupt 0 / PWM fault input |
| Pin 22 | RB1/AN10/INT1 — PORTB bit 1 / analog input channel 10 / external interrupt 1 |
| Pin 23 | RB2/AN8/INT2 — PORTB bit 2 / analog input channel 8 / external interrupt 2 |
| Pin 24 | RB3/AN9/CCP2 — PORTB bit 3 / analog input channel 9 / Capture-Compare-PWM 2 |
| Pin 25 | RB4/AN11/KBI0 — PORTB bit 4 / analog input channel 11 / interrupt-on-change bit 0 |
| Pin 26 | RB5/KBI1/PGM — PORTB bit 5 / interrupt-on-change bit 1 / ICSP LVP programming |
| Pin 27 | RB6/KBI2/PGC — PORTB bit 6 / interrupt-on-change bit 2 / ICSP clock (ICD) |
| Pin 28 | RB7/KBI3/PGD — PORTB bit 7 / interrupt-on-change bit 3 / ICSP data (ICD) |
Typical Applications
PIC18F26K20-I/SO is suitable for 6 applications: Battery-Powered Sensor Nodes, Portable Medical Devices, Industrial Control Modules, Home Automation Hubs, Automotive Body Electronics, USB-to-UART Bridge Modules.
Battery-Powered Sensor Nodes
The PIC18F26K20-I/SO is well suited to battery-powered wireless sensor nodes because its nanoWatt XLP technology delivers deep-sleep current below 100 nA, allowing years of operation from a single CR2032 coin cell. The 64 KB of Flash accommodates over-the-air firmware update stacks (e.g. LoRaWAN or BLE), while the 3936 bytes of SRAM comfortably handles sensor buffering and protocol state. The 64 MHz (16 MIPS) CPU speed is fast enough to wake, take an ADC reading, run a calibration, transmit, and return to sleep within milliseconds - the regime where total average current is dominated by sleep current. Compared with switching regulators, the integrated analog and digital peripherals reduce external parts count, which extends battery life by eliminating quiescent losses.
Recommended
Portable Medical Devices
The PIC18F26K20-I/SO fits portable medical device designs where low sleep current, deterministic I/O, and a well-established toolchain are critical. The 10-bit ADC with up to 17 channels supports multiple sensor inputs (temperature, pulse oximeter front-end, battery monitor) on a single chip, while the 64 KB Flash holds real-time scheduling code and USB/HID class drivers. The -I industrial temperature grade (-40C to +85C) covers the range encountered in home-health devices. MPLAB X IDE and the XC8 C compiler are both IEC 62304-friendly with version-locked libraries, which simplifies regulatory documentation. The SOIC-28 wide-body package is easy to inspect and rework during low-volume production runs.
Recommended
Industrial Control Modules
The PIC18F26K20-I/SO serves industrial control modules (sensor transmitters, valve drivers, HVAC peripherals) where 1.8 V to 3.6 V operation, deterministic interrupts, and reliable Flash retention matter. The two analog comparators enable direct zero-crossing detection of 24 V industrial signals through resistor dividers, while the ECCP module generates PWM for motor control up to kHz frequencies. The 25 I/O pins comfortably drive keypad inputs, status LEDs, and an RS-485 link through an external transceiver, all from the same SOIC-28 package. The wide industrial temperature range and stable internal 16 MHz oscillator (with PLL to 64 MHz) ensure consistent timing across production units without external crystal tuning.
Recommended
Home Automation Hubs
The PIC18F26K20-I/SO is appropriate for low-cost home automation hubs and bridges (Zigbee/BLE-to-WiFi gateways, smart thermostats, remote-controlled lighting) that need 64 KB of Flash for protocol stacks and a low sleep current for always-on wall-powered operation. The MSSP module supports both SPI (for radio modules) and I2C (for sensor hubs and EEPROM), while the USARTs handle debug console and external modem interfaces. The 1.8 V to 3.6 V supply range matches typical Li-Ion / USB-powered regulator outputs. The SOIC-28 wide-body package simplifies hand-assembly for prototype runs at small home-automation companies, and MPLAB X IDE has reference code for common wireless stacks.
Recommended
Automotive Body Electronics
The PIC18F26K20-I/SO is suitable for non-safety automotive body electronics (interior lighting, seat controllers, mirror adjusters, accessory multiplexers) where the extended -I grade handles under-dash thermal conditions. The PIC18F family has well-documented automotive-grade migration paths to AEC-Q100 parts in the same SOIC-28 footprint, allowing the same PCB to be reused for higher-reliability variants when production volumes justify qualification. The two CCP/ECCP modules support dual-axis servo or motor control, while the 10-bit ADC handles battery voltage monitoring (with external divider) and current sensing through op-amps. The internal 16 MHz oscillator with PLL provides timing accuracy sufficient for LIN bus communication at 19.2 kbps through software bit-banging.
Recommended
USB-to-UART Bridge Modules
The PIC18F26K20-I/SO serves as the main controller in low-cost USB-to-UART, USB-to-SPI, or USB-to-I2C bridge modules where the Flash headroom supports both CDC/HID class firmware and configuration utilities. Although the K20 itself does not include a USB peripheral, the PIC18F26K80-I/SO in the same SOIC-28 footprint adds USB and is a more natural choice when USB is required. The K20 still fits the role of bridge controller when paired with an external USB-serial chip such as the MCP2221A, and the 64 KB Flash holds the multiplexer/firmware update logic. The 1.8 V to 3.6 V range simplifies designs that operate from a single 3.3 V LDO rail.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F26K20-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F26K20-E/SO | PIC18F26K22-I/SO | PIC18F25K20-I/SO | PIC18F26J13-I/SO | PIC18F2620-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SOIC-28 | SOIC-28 (same) | SOIC-28 (same) | SOIC-28 (same) | SOIC-28 (same) | SOIC-28 (same) |
| Flash Memory | 64 KB | 64 KB | 64 KB | 32 KB (-50%) | 64 KB | 64 KB |
| SRAM | 3936 bytes | 3936 bytes | 3896 bytes | 1536 bytes (-61%) | 3760 bytes | 3936 bytes |
| Maximum CPU Speed | 64 MHz (16 MIPS) | 64 MHz (16 MIPS) | 64 MHz (16 MIPS) | 64 MHz (16 MIPS) | 48 MHz (12 MIPS, -25%) | 40 MHz (10 MIPS, -38%) |
| Operating Voltage Range | 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 | 2.0 V to 3.6 V | 4.2 V to 5.5 V (+39% higher VDD) |
| I/O Pins | 25 | 25 | 25 | 25 | 22 | 25 |
| Low-Power Technology | nanoWalt XLP (deep sleep < 100 nA) | nanoWatt XLP (same) | nanoWatt XLP + CIPs | nanoWatt XLP (same) | No XLP deep sleep | No nanoWatt XLP |
Key Differentiators
- True 1.8 V minimum VDD operation with nanoWatt XLP (vs PIC18F2620-I/SO)
- 64 KB Flash with 16 MIPS performance (vs PIC18F25K20-I/SO)
- Higher CPU clock ceiling than the J-series (vs PIC18F26J13-I/SO)
Design Notes
For minimum sleep current on the PIC18F26K20-I/SO, place the device in deep-sleep mode (DSDS = 1 with DSEN bit set) which reduces core current below 100 nA per manufacturer datasheet. Before entering deep sleep, disable the ADC module, switch the system clock to the 31 kHz LF oscillator, and disable the WDT unless a periodic wake-up is required. Pull all unused I/O pins to a defined logic level (either VDD or VSS) to avoid floating-input leakage currents that can dominate quiescent budget in low-duty-cycle sensor applications.
Place at least one 100 nF ceramic decoupling capacitor directly between each VDD pin and the adjacent VSS pin, with traces kept as short as possible (less than 3 mm). Add a bulk 10 uF tantalum or ceramic capacitor on the main 3.3 V rail close to the MCU. For the 28-SOIC wide-body footprint, route the ICSP signals (PGC/PGD/MCLR) to a 6-pin header or Tag-Connect pads on the board edge so that in-circuit debugging remains possible without rework. Keep analog inputs (ANx pins) away from high-current switching traces to preserve ADC accuracy.
A common pitfall when migrating from PIC16 to PIC18 is forgetting to configure the CONFIG words (fuses) for the desired oscillator mode and watchdog state; unprogrammed CONFIG defaults to LF oscillator and WDT enabled, which can confuse new designs. Another pitfall is using the analog input channels without first clearing the corresponding TRIS bit and setting the ANSEL bit to disable the digital input buffer on that pin - otherwise the digital input buffer draws bias current that injects noise into the ADC. Finally, ensure the MCLR pin is either tied to VDD through a 10 kohm resistor or driven by the supervisor; leaving MCLR floating causes spurious resets.
Compliance Information
RoHS compliant per Microchip product page and LCSC listing. Lead-free (Pb-free) per manufacturer datasheet ordering information. AEC-Q100 qualification is not applicable to this standard industrial-grade part - automotive-grade PIC18F parts require explicit -VAO or -E automotive suffixes.
