PIC18F25K50-I/SO - 32KB Flash USB MCU 48MHz 28-SOIC | Microchip
MPN: PIC18F25K50-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.63 | $4.63 |
| 10 | $4.21 | $42.10 |
| 100 | $3.74 | $374.00 |
| 500 | $3.3 | $1,650.00 |
| 1,000 | $2.95 | $2,950.00 |
PIC18F25K50-I/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripherals such as timers, ADC, communication ports, and I/O. The PIC18F25K50 belongs to the PIC18 family of RISC microcontrollers, which occupy the mid-tier of the PIC architecture hierarchy (PIC10/12/16 -> PIC18 -> PIC24/dsPIC -> PIC32). Its defining role is the addition of a hardware USB 2.0 Full-Speed device controller, eliminating the need for an external USB PHY in cost-sensitive embedded links.
Key features include 32 KB self-read/write Flash, 2 KB RAM, 256 bytes EEPROM, a 10-bit ADC with up to 14 channels, two comparators, Enhanced Capture/Compare/PWM, two USART (one LIN-capable), SPI, I2C, and an internal 48 MHz oscillator tunable against the USB host clock for accuracy. The XLP nanoWatt technology provides sleep currents as low as a few nanoamperies for battery-backed USB devices. USB Suspend/Resume is supported for full USB-IF compliance.
Typical applications include USB HID peripherals (keyboards, mice, game controllers), USB-to-UART bridges, low-cost data loggers, sensor interfaces, consumer toys, and industrial control nodes. The 48 MHz core plus USB makes the part well suited when designers need to host a CDC/HID/MSD stack without paying for an ARM Cortex-M0.
When designing with this device, ensure the VUSB pin has the recommended 220 nF decoupling and the D+/D- traces are 90-ohm differential length-matched. The internal 48 MHz oscillator is trimmed at the factory, but active clock tuning from the USB host is recommended for jitter-sensitive isochronous endpoints.
This page synthesizes drop-in alternatives, comparison data, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18F25K50-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 PIC18F25K50-I/SO (same form factor and footprint) — differing in Package, ADC, Operating Temperature, Program Memory (Flash), Communication.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K50-E/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K50T-I/SO
✅ Drop-In✓ In Stock
$1.84 / Unit
View Datasheet →PIC18F24K50-I/SO
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.05 / Unit
View Datasheet →PIC18F25K42-I/SO
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F25J50-I/SO
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.78 / Unit
View Datasheet →PIC18F25K50-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| Program Memory | 32 KB Flash (self read/write) |
| RAM | 2 KB |
| EEPROM | 256 bytes |
| Maximum CPU Frequency | 48 MHz |
| Operating Voltage Range | 2.5 V to 5.5 V |
| USB Module | USB 2.0 Full-Speed (12 Mbit/s) Device |
| ADC | 10-bit, up to 14 channels |
| Comparators | 2 |
| Timers | 4 (Timer0/1/2/3) |
| Communication | 2x USART (LIN), SPI, I2C |
| PWM Outputs | Enhanced CCP, up to 5 channels |
| I/O Pins | 25 (typical, 28-pin SOIC) |
| Package | 28-pin SOIC (SO) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC18F25K50-I/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input, active low |
| Pin 2 | RA0 — Digital I/O / analog input AN0 |
| Pin 3 | RA1 — Digital I/O / analog input AN1 |
| Pin 4 | RA2 — Digital I/O / analog input AN2 |
| Pin 5 | RA3 — Digital I/O / analog input AN3 |
| Pin 6 | RA4 — Digital I/O / analog input AN4 / Timer0 gate |
| Pin 7 | RA5 — Digital I/O / analog input AN5 |
| Pin 8 | RE3 — Digital I/O (input only on this pin) |
| Pin 9 | OSC1 — Crystal oscillator input / external clock |
| Pin 10 | OSC2 — Crystal oscillator output |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | VSS — Ground reference |
| Pin 13 | RA7 — Digital I/O / oscillator output |
| Pin 14 | VUSB — USB internal 3.3V regulator output (decouple with 220nF) |
| Pin 15 | D- — USB data minus line |
| Pin 16 | D+ — USB data plus line |
| Pin 17 | RC4 — Digital I/O / USB sense input |
| Pin 18 | RC5 — Digital I/O / USB sense output |
| Pin 19 | RC6 — Digital I/O / USART TX |
| Pin 20 | RC7 — Digital I/O / USART RX |
| Pin 21 | RB4 — Digital I/O / interrupt-on-change |
| Pin 22 | RB5 — Digital I/O / interrupt-on-change |
| Pin 23 | RB6 — Digital I/O / ICD clock |
| Pin 24 | RB7 — Digital I/O / ICD data |
| Pin 25 | RC0 — Digital I/O |
| Pin 26 | RC1 — Digital I/O / analog input AN12 |
| Pin 27 | VSS — Ground reference |
| Pin 28 | VDD — Positive supply voltage |
Typical Applications
PIC18F25K50-I/SO is suitable for 6 applications: USB HID Peripherals, USB-to-UART Bridge, USB Sensor Data Logger, Industrial Control Nodes, USB Bootloader Host, Consumer USB Toys and Gadgets.
USB HID Peripherals
The PIC18F25K50-I/SO is ideally suited for USB HID devices such as keyboards, mice, and game controllers because its integrated USB 2.0 Full-Speed transceiver eliminates external PHY cost. The 48 MHz core runs USB stacks plus HID report processing with sufficient headroom; 32 KB Flash holds HID class driver and application. The 25 I/O pins support matrix-scanned key grids and quadrature encoders. Per Microchip datasheet, the internal 48 MHz oscillator can be tuned against the USB host SOF for sub-percent frequency accuracy, critical for HID compliance testing.
Recommended
USB-to-UART Bridge
For USB-to-UART bridges and CDC virtual COM port designs, the PIC18F25K50-I/SO provides a compact BOM with the on-chip USB transceiver and dual USART peripherals (one LIN-capable). The 2 KB RAM handles USB endpoint buffers plus CDC line coding without external memory. Operating from 2.5V-5.5V means the same design works at 3.3V logic levels or 5V RS-232 levels via external transceiver. Reference firmware from Microchip (MLA/MPLAB Harmony-style stacks) implements this in well under 16 KB of Flash.
Recommended
USB Sensor Data Logger
Battery-powered USB sensor loggers benefit from the PIC18F25K50-I/SO XLP nanoWatt technology, which delivers sub-uA sleep currents for weeks of standby life. The 10-bit ADC with up to 14 channels reads temperature, voltage, or analog sensors, while the 32 KB Flash stores logs and configuration. The integrated USB allows the same port to charge and stream data when tethered. Per Microchip documentation, sleep mode with RTC wake can extend battery life beyond one year on a single coin cell in typical duty cycles.
Recommended
Industrial Control Nodes
In factory automation nodes, the PIC18F25K50-I/SO serves as a USB-attached sensor hub or LIN bus node, leveraging its 5V tolerance on digital I/O for direct interface to industrial sensor clusters. The Enhanced Capture/Compare/PWM modules drive stepper or DC motor sub-systems at up to 5 PWM channels. The 25 I/O pins accommodate SPI master control of ADCs, I2C sensor arrays, and discrete I/O. Operating from -40C to +85C industrial temperature, it survives cabinet-mounted installations in factory environments.
Recommended
USB Bootloader Host
The PIC18F25K50-I/SO self-read/write Flash enables USB-based bootloader designs that update firmware in the field without a programmer. A small bootloader in protected Flash (top 2 KB region) implements the USB DFU or HID-based loader, while the main application occupies the lower 30 KB. End users update firmware by holding a button at power-up to enter bootloader mode. The 32 KB total Flash gives generous room for both bootloader and feature firmware with margin for growth.
Recommended
Consumer USB Toys and Gadgets
Consumer USB toys, custom gamepads, and novelty USB gadgets leverage the PIC18F25K50-I/SO's low cost and integrated USB to minimize BOM count. The 32 KB Flash supports multi-mode device firmware (HID + CDC + vendor-class), while the 2 KB RAM holds LED animation buffers and button debounce state. With a 28-pin SOIC footprint, the part fits compact enclosures and operates from USB VBUS directly at 5V. Microchip's free USB stack with HID/CDC source simplifies hobbyist and small-OEM designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F25K50-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K50-E/SO | PIC18F25K50T-I/SO | PIC18F24K50-I/SO | PIC18F25J50-I/SO |
|---|---|---|---|---|---|
| Package | 28-SOIC (SO) | 28-SOIC (SO) - same | 28-SOIC (SO) - same | 28-SOIC (SO) - same | 28-SOIC (SO) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 16 KB | 32 KB |
| RAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| USB Module | USB 2.0 FS Device | USB 2.0 FS Device | USB 2.0 FS Device | USB 2.0 FS Device | USB 2.0 FS Device |
| Operating Temperature | -40C to +85C | -40C to +125C (extended) | -40C to +85C | -40C to +85C | -40C to +85C |
| Operating Voltage | 2.5V to 5.5V | 2.5V to 5.5V | 2.5V to 5.5V | 2.5V to 5.5V | 2.7V to 3.6V (3.3V core) |
| Max CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
Key Differentiators
- Integrated USB 2.0 Full-Speed transceiver on-chip (vs PIC18F4550-I/P)
- XLP (eXtreme Low Power) nanoWatt technology (vs PIC18F2550-I/SO)
- Self-read/write Flash for bootloaders (vs PIC18F25K20-I/SO)
- Wide 2.5V-5.5V VDD operating range (vs PIC18F25J50-I/SO)
Design Notes
Place a 220 nF decoupling capacitor as close as possible to the VUSB pin (pin 14) to stabilize the internal 3.3V USB regulator. Use a 90-ohm differential pair for D+ (pin 16) and D- (pin 15) with length matching within 150 mil. Route D+/D- away from high-speed digital signals and clock traces. Add bulk 4.7uF and 100nF capacitors on VDD (pins 11, 28) and tie VSS (pins 12, 27) to a low-impedance ground plane. Microchip datasheet section 17.2 provides the reference PCB layout.
The PIC18F25K50-I/SO has two VDD pins (11 and 28) and two VSS pins (12 and 27); both pairs must be connected for proper operation. For USB bus-powered designs, derive 5V from VBUS through a ferrite bead and 10uF bulk capacitor, then run VDD directly from VBUS (no regulator needed since the part supports 5V). For self-powered designs, isolate VBUS from VDD with a schottky diode and provide 4.7uF bypass. Reference Microchip AN948 'USB Migration' for detailed power topologies.
Enable the active clock tuning feature (ACT) from the USB host Start-of-Frame packets to keep the internal 48 MHz oscillator within +/- 0.25% of nominal. This is required for isochronous USB endpoints and recommended for HID devices passing USB-IF compliance. Configure ACT via the ACTCON register after enumeration completes. Without ACT, the internal oscillator drift may exceed USB timing specifications over temperature.
Do not leave the MCLR pin (pin 1) floating - always tie it to VDD through a 10kohm pull-up resistor and add a 100nF capacitor to ground for noise filtering, unless using the internal MCLR disabled mode. Do not connect the OSC1/OSC2 pins to anything when using the internal 48 MHz oscillator; leave them as no-connect or terminate per datasheet. Do not exceed 5.5V on any pin including D+/D-; transient suppression is recommended for industrial environments.
Compliance Information
RoHS and REACH compliant per Microchip product page. AEC-Q100 not applicable for non-automotive 8-bit MCU. Lead-free (Pb-free) packaging standard.
