PIC18F25K20-I/SO - 8-bit 64MHz 32KB Flash MCU 28-SOIC | Microchip
MPN: PIC18F25K20-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.36 | $336.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.55 | $2,550.00 |
PIC18F25K20-I/SO Overview
What is an 8-bit microcontroller? An 8-bit microcontroller (MCU) is a small computer on a single integrated circuit that processes data in 8-bit chunks, integrating a CPU, RAM, non-volatile program memory (Flash), and peripherals such as ADC, timers, and communication interfaces. Within the broader semiconductor taxonomy, 8-bit MCUs sit beneath microcontrollers and digital ICs, and remain the lowest-cost choice for deterministic, low-power embedded control. The PIC18F25K20 belongs to Microchip's PIC18 XLP family, a family that pairs a RISC core with nanoWatt XLP power management to deliver long battery life in always-on applications.
Key features include 64 MHz operation yielding 16 MIPS throughput, 32 KB self-programmable Flash, 1536 bytes SRAM, 256 bytes EEPROM, 25 digital I/O, a 10-bit ADC with up to 11 channels, two analog comparators, two 8-bit timers and three 16-bit timers, MSSP (SPI/I2C), enhanced USART, two capture/compare/PWM modules plus one enhanced CCP, and nanoWatt XLP technology offering sub-µA sleep currents. The wide 1.8 V to 3.6 V core voltage range (verified by the 4.2 V to 5.5 V datasheet VDD range for this variant) plus nanoWatt modes enables coin-cell and energy-harvesting designs.
The architecture uses an enhanced PIC18 Harvard RISC core with a hardware multiplier, 31-level stack, and C-friendly instruction set, allowing developers to program in C18/XC8 with predictable interrupt response. On-chip debug via ICSP and ICD support simplifies in-circuit emulation for prototype development.
Typical applications include industrial sensor nodes, low-power remote controls, battery-powered instrumentation, HVAC controllers, automotive body modules, and consumer appliances. The SOIC-28 footprint gives generous PCB escape room compared with QFN alternatives, simplifying hand-soldering and rework in low-volume builds.
A primary design consideration is that the PIC18F25K20 operates from 1.8 V to 3.6 V core logic and the -I version supports the industrial -40°C to +85°C range; if your rail is 5 V you need a different PIC18 K-series variant. Use an external supervisor/reset IC for noisy industrial environments, and add 100 nF + 10 µF decoupling close to VDD/AVDD/VSS/AVSS pairs.
This page consolidates distributor pricing, parametric cross-references, drop-in alternatives, and practical PCB design notes that go beyond the manufacturer datasheet, helping engineers select, source, and lay out the PIC18F25K20-I/SO with confidence.
Drop-in alternatives for PIC18F25K20-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 PIC18F25K20-I/SO (same form factor and footprint) — differing in Package, ADC, Operating Temperature, Timers, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K20-I/SS
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18F25K20-I/SP
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC18F25K22-I/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC18F26K20-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K80-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F24K20-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K20-I/SO Maximum Ratings & Electrical Characteristics
| Family | PIC® 18F XLP |
| Core | 8-bit PIC18 RISC |
| Program Memory (Flash) | 32 KB (16K × 16) |
| SRAM | 1536 bytes |
| EEPROM | 256 bytes |
| Maximum CPU Frequency | 64 MHz (16 MIPS) |
| Supply Voltage (VDD) | 1.8 V to 3.6 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 11 channels |
| Comparators | 2 |
| Timers | 2 × 8-bit, 3 × 16-bit |
| CCP/ECCP Modules | 2 CCP + 1 ECCP |
| Serial Interfaces | MSSP (SPI/I²C), EUSART |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Package | 28-SOIC (SO, 300 mil) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC18F25K20-I/SO Pin Configuration
| Pin 1 | RA0/AN0/CVREF/ULPWU — PORTA bit 0 / analog input 0 / CV reference / ultra-low-power wake-up |
| Pin 2 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 3 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / ADC VREF- |
| Pin 4 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC VREF+ |
| Pin 5 | RA4/T0CKI/RCV — PORTA bit 4 / Timer0 clock input / RCV |
| Pin 6 | RA5/AN4/SS/HLVDIN — PORTA bit 5 / analog input 4 / SPI SS / HLVD input |
| Pin 7 | RA6 — PORTA bit 6 / oscillator pin (OSC2) |
| Pin 8 | RA7 — PORTA bit 7 / oscillator pin (OSC1) |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Positive supply |
| Pin 11 | RB0/INT0/AN12 — PORTB bit 0 / external interrupt 0 |
| Pin 12 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 13 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 14 | RB3/AN9/CCP2 — PORTB bit 3 / analog input 9 / CCP2 output |
| Pin 15 | RB4/AN10/KBI0 — PORTB bit 4 / analog input 10 / KBI interrupt |
| Pin 16 | RB5/AN11/KBI1 — PORTB bit 5 / analog input 11 / KBI interrupt |
| Pin 17 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 18 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply |
| Pin 21 | RC0/SOSCO — PORTC bit 0 / secondary oscillator output |
| Pin 22 | RC1/SOSCI — PORTC bit 1 / secondary oscillator input |
| Pin 23 | RC2/CCP1 — PORTC bit 2 / CCP1 output |
| Pin 24 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 25 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 26 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 27 | RC6/TX/CK — PORTC bit 6 / EUSART TX / clock |
| Pin 28 | RC7/RX/DT — PORTC bit 7 / EUSART RX / data |
Typical Applications
PIC18F25K20-I/SO is suitable for 7 applications: Industrial Sensor Nodes, Battery-Powered Remote Controls, HVAC Building Controllers, Automotive Body Modules, Consumer Appliance Control, Medical Monitoring Accessories, IoT Edge Sensor Hub.
Industrial Sensor Nodes
The PIC18F25K20-I/SO fits industrial sensor nodes that need 32 KB Flash for Modbus RTU stacks plus application logic, 1536 B RAM for protocol buffers, and the nanoWatt XLP sleep current under 100 nA to extend battery life on wireless HART or LoRa attachments. With 10-bit ADC sampling at up to 11 channels, the F25K20 reads thermocouples, RTDs, and 4-20 mA loop currents through signal conditioning, while two comparators implement window-detect alarms without using the ADC. The MSSP peripheral drives SPI or I2C sensors and the EUSART handles RS-485 Modbus with hardware addressing, so a single chip covers acquisition, processing, and comms in a -40 °C to +85 °C environment.
Recommended
Battery-Powered Remote Controls
The PIC18F25K20-I/SO is well suited to handheld remote controls and BLE/Wi-Fi host MCUs because its nanoWatt XLP sleep current under 100 nA allows coin-cell operation for years, and its 64 MHz / 16 MIPS performance is enough for button debouncing, IR protocol encoding, and simple LCD driving. The CCP/ECCP peripherals generate precise carrier frequencies for sub-GHz radios, while the 25 I/O pins drive key matrices up to 5x5 without external port expanders. Adding the F25K20's 1.8 V to 3.6 V range, designers can directly run from a single lithium coin cell without LDO loss.
Recommended
HVAC Building Controllers
The PIC18F25K20-I/SO handles HVAC damper actuators, fan controllers, and zone thermostats thanks to its 10-bit ADC sampling thermistor bridges, 2 CCP plus 1 ECCP module generating PWM outputs for variable-speed fans and motorized valves, and its industrial -40 °C to +85 °C temperature rating. The 32 KB Flash accommodates BACnet MS/TP or proprietary HVAC protocol stacks alongside control logic, and the 25 I/O pins are sufficient to drive triac interfaces, status LEDs, and keypad inputs on a single chip. Watchdog timer plus fail-safe clock monitor improve field reliability in unattended installations.
Recommended
Automotive Body Modules
Although the PIC18F25K20-I/SO is not AEC-Q100 qualified, it is used in non-safety automotive body applications such as interior lighting controllers, seat-position memory, and door modules that operate below the strict AEC-Q envelope. Its 25 I/O pins drive LED arrays via MOSFET drivers and read Hall-effect sensors for seat-position feedback, while the 10-bit ADC samples battery voltage for brown-out detection. The MSSP SPI port connects to LED driver ICs and the EUSART supports LIN-bus communication via external transceivers, providing a complete body-module platform for non-critical subsystems.
Recommended
Consumer Appliance Control
The PIC18F25K20-I/SO is a strong fit for white-goods and small appliance controllers where cost, reliability, and code space matter. Its 32 KB Flash is sufficient for user-interface state machines, sensor-fusion algorithms, and safety logic in washing machines, dishwashers, and microwave ovens, while the 16 MIPS throughput handles BLDC commutation via the ECCP peripheral. The 10-bit ADC reads motor current, NTC thermistors, and water-level sensors, and the nanoWatt XLP modes let the controller enter standby when the appliance is idle, dropping wall-plug power below 0.1 W.
Recommended
Medical Monitoring Accessories
The PIC18F25K20-I/SO fits medical monitoring accessories such as pill dispensers, sleep trackers, and personal-health peripherals that operate at low voltages and require low quiescent current. Its 10-bit ADC reads photoplethysmography (PPG) sensor signals, thermistors, and battery voltage, while the MSSP I2C port talks to external accelerometers and BLE modules. The 32 KB Flash supports Bluetooth Low Energy profile stacks or custom firmware for dosage scheduling. Note: medical device certification requires IEC 60601 and FDA/510(k) clearance outside the MCU - the F25K20 supports the embedded electronics layer only.
Recommended
IoT Edge Sensor Hub
The PIC18F25K20-I/SO serves as the host MCU for IoT edge sensor hubs that aggregate multiple I2C/SPI sensors and forward data over UART, Wi-Fi, or LoRa. Its 64 MHz clock is enough to run JSON parsing and TLS handshakes if required, while the 25 I/O pins handle multiple sensor interrupts. The MSSP peripheral drives two I2C buses when paired with a port expander, and the 32 KB Flash supports MQTT-SN or CoAP libraries alongside application logic, making the F25K20 a flexible choice for low-cost edge nodes.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F25K20-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K20-I/SS | PIC18F25K20-I/SP | PIC18F25K22-I/SO | PIC18F26K20-I/SO | PIC18F24K20-I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC (SO, 300 mil) | 28-SSOP (SS, 209 mil) | 28-SPDIP (SP, 300 mil) | 28-SOIC (SO, 300 mil) | 28-SOIC (SO, 300 mil) | 28-SOIC (SO, 300 mil) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 64 KB | 32 KB | 16 KB |
| SRAM | 1536 B | 1536 B | 3896 B | 768 B | 1536 B | |
| Maximum Frequency | 64 MHz (16 MIPS) | 64 MHz (16 MIPS) | 64 MHz (16 MIPS) | 48 MHz (12 MIPS) | 64 MHz (16 MIPS) | |
| Operating Voltage | 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 | 1.8 V to 3.6 V | |
| I/O Pins | 25 | 25 | 25 | 25 | 24 | |
| Operating Temperature | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | |
| Unit Price (qty 1, USD) | $4.20 | $4.50 | $4.80 | $3.95 | $5.10 |
Key Differentiators
- Best-in-class nanoWatt XLP extreme-low-power consumption (vs PIC18F25K80-I/SO)
- 64 MHz / 16 MIPS throughput at the same price tier (vs PIC18F25K80-I/SO)
- 32 KB Flash / 1536 B SRAM balanced density (vs PIC18F24K20-I/SO)
Design Notes
Estimated: at 64 MHz CPU, 3.3 V VDD, full I/O toggling, the PIC18F25K20-I/SO core draws roughly 9 mA. Add decoupling close to every VDD/VSS pin pair: a 100 nF ceramic within 2 mm of the IC and a bulk 10 µF tantalum or ceramic on the board-level rail. nanoWatt XLP sleep currents drop below 100 nA when configured correctly, so disable unused peripherals and unused ADC channels to minimize quiescent draw.
Place the 28-SOIC land pattern with at least 0.5 mm clearance to adjacent traces, and route the ICSP pins (RB6/PGC, RB7/PGD) as short straight lines to a 2x3 ICSP header for in-circuit debugging. According to the Microchip PIC18F25K20 datasheet pinout, RA6/RA7 can be repurposed as general I/O only when the oscillator is configured for an internal-only mode; if you use an external crystal, isolate those traces from noisy digital lines.
Do not exceed 3.6 V on VDD on the PIC18F25K20-I/SO; this is a 3.3 V part, not a 5 V part - the legacy F-series PIC18 (PIC18F2520) operates to 5 V but the F25K20 has a different core voltage rating. Use a 3.3 V LDO such as MCP1700 or MCP1727 upstream. Also note that RE3 is missing on this 28-pin variant, so external MCLR reset functionality must be brought out through the ICSP dedicated pin (pin 1, RA6/RA7 oscillator function shared).
For SPI buses running above 8 MHz on the MSSP peripheral, add 33 Ω series resistors at SCK/SDO to dampen ringing on long traces and ensure the slave device sees a clean edge. According to Microchip PIC18F25K20 family design notes, the MSSP peripheral supports both mode 0 and mode 3 SPI; verify CPOL/CPHA against the slave datasheet. For I2C buses, include 4.7 kΩ pull-ups to VDD and limit total bus capacitance to 400 pF.
Compliance Information
RoHS and REACH compliant per Microchip material declaration. Not AEC-Q100 qualified; for automotive use, select PIC18F46K80-I/PQ or similar AEC-Q100-qualified variants.
