PIC18LF25K50-I/SS - 8-Bit 48MHz 32KB Flash USB MCU | Microchip
MPN: PIC18LF25K50-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.85 | $28.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.75 | $1,750.00 |
PIC18LF25K50-I/SS Overview
An 8-bit microcontroller (MCU) is a single-chip computer with an 8-bit data bus that executes instructions from on-chip program memory; within the hierarchy, it sits under microcontroller -> embedded processor -> semiconductor device. The PIC18 family uses a modified Harvard RISC architecture with separate program and data buses, and the K50 sub-family adds a built-in USB 2.0 transceiver, eliminating the external crystal typically required for USB clocking.
Key features include 32KB self-read/write Flash, 2KB RAM, 256 bytes of EEPROM, an internal 48MHz oscillator with Active Clock Tuning from the USB host, an 8x8 hardware multiplier, and 25 I/O pins. The integrated USB module is USB-IF certified and supports control, interrupt, bulk, and isochronous transfers. Power-managed modes include Run, Idle, Sleep, and multiple low-power Sleep variants drawing nanoamp-level currents.
The architecture combines a 16-bit instruction word with an 8-bit data path, providing C-friendly code density while retaining predictable interrupt latency. The Active Clock Tuning block adjusts the internal oscillator against the USB SOF packet, so the 48MHz USB clock stays within the +/-0.25% required by the USB 2.0 specification without an external crystal.
Typical applications include USB HID peripherals (keyboards, mice, custom input devices), USB-to-UART bridges, low-power sensor loggers, battery-powered data acquisition, and consumer electronics with USB connectivity. Its XLP technology makes it suitable for coin-cell or energy-harvesting designs where Sleep current must stay in the nanoamp range.
Designers should plan for 5V-tolerant digital inputs on most I/O pins and provide a regulated 1.8V to 3.6V supply for the LF variant. Decoupling requires a 0.1uF ceramic capacitor close to VDD and a 10uF bulk capacitor if the USB bus is the sole power source. The internal oscillator's USB-driven calibration removes the need for an external crystal when USB is present.
This page synthesizes distributor pricing, drop-in alternative inventory, and practical design notes that are not found in the manufacturer datasheet alone, including a same-package cross-reference matrix for second-source planning.
Drop-in alternatives for PIC18LF25K50-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 PIC18LF25K50-I/SS (same form factor and footprint) — differing in ADC, Package, Core Architecture, Operating Voltage Range, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K50-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF25K50-I/SO
✅ Drop-In✓ In Stock
$2.15 / Unit
View Datasheet →PIC18LF25K50-E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF24K50-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF25K42-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF13K50-I/SS
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →PIC18LF25K50-I/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18, 8-bit RISC |
| Program Memory (Flash) | 32 KB (16K x 16) |
| Data RAM | 2 KB |
| EEPROM | 256 bytes |
| Maximum CPU Frequency | 48 MHz |
| Instruction Cycle | 200 ns (8 MHz input) / 83 ns (48 MHz) |
| MIPS Performance | 16 MIPS |
| Operating Voltage Range | 1.8 V to 3.6 V (LF variant) |
| I/O Pins | 25 |
| USB Module | USB 2.0 Full-Speed (12 Mbps) Device |
| Internal Oscillator | 48 MHz with USB Active Clock Tuning |
| Hardware Multiplier | 8x8 single-cycle |
| ADC | 10-bit, up to 14 channels |
| Timers | 4 (Timer0/1/2/3) |
| Enhanced CCP/ECCP | 2 ECCP + 2 CCP |
| Package | 28-pin SSOP (5.30 mm body width) |
| Operating Temperature | -40C to +85C (Industrial) |
| RoHS Status | Compliant |
PIC18LF25K50-I/SS Pin Configuration
| Pin 1 | RA0/AN0/C1IN+/VCAP — Analog input 0 / comparator 1 input / core voltage decoupling |
| Pin 2 | RA1/AN1/C1IN- — Analog input 1 / comparator 1 input |
| Pin 3 | RA2/AN2 — Analog input 2 |
| Pin 4 | RA3/AN3/VREF+ — Analog input 3 / ADC positive reference |
| Pin 5 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Pin 6 | RA5/AN4/C2IN+/VCAP — Analog input 4 / comparator 2 input |
| Pin 7 | VSS — Ground reference |
| Pin 8 | RA7/OSC1/CLKI — Crystal oscillator input / external clock input |
| Pin 9 | RA6/OSC2/CLKO — Crystal oscillator output / clock output |
| Pin 10 | RC0/SOSCO — Digital I/O / secondary oscillator output |
| Pin 11 | RC1/SOSCI — Digital I/O / secondary oscillator input |
| Pin 12 | RC2/CCP1 — Digital I/O / Enhanced CCP1 output |
| Pin 13 | VUSB — USB internal transceiver 3.3V regulator output (bypass with cap) |
| Pin 14 | D+ — USB D+ data line |
| Pin 15 | D- — USB D- data line |
| Pin 16 | RC4 — Digital I/O |
| Pin 17 | RC5 — Digital I/O |
| Pin 18 | RC6/TX/CK — Digital I/O / UART TX / I2C clock |
| Pin 19 | RC7/RX/DT — Digital I/O / UART RX / I2C data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage (1.8V to 3.6V for LF) |
| Pin 22 | RB0/AN12 — Digital I/O / analog input 12 |
| Pin 23 | RB1/AN10 — Digital I/O / analog input 10 |
| Pin 24 | RB2/AN8 — Digital I/O / analog input 8 |
| Pin 25 | RB3/AN9 — Digital I/O / analog input 9 |
| Pin 26 | RB4/AN11 — Digital I/O / analog input 11 |
| Pin 27 | RB5/AN13 — Digital I/O / analog input 13 |
| Pin 28 | RB6/ICSPCLK — Digital I/O / ICSP clock |
Typical Applications
PIC18LF25K50-I/SS is suitable for 7 applications: USB HID Peripherals (Keyboard, Mouse, Custom Input Devices), USB-to-UART Bridge / Virtual COM Port, Battery-Powered Sensor Logger with USB Recharge, Low-Speed USB Audio Class Device (Headset Adapter), Industrial Data Acquisition over USB, Consumer Electronics with USB Charging Port, USB-Connected Programmer / Debug Probe Bridge.
USB HID Peripherals (Keyboard, Mouse, Custom Input Devices)
The PIC18LF25K50-I/SS is purpose-built for USB HID peripherals thanks to its integrated USB 2.0 full-speed transceiver, on-chip SIE, and 48 MHz internal oscillator with Active Clock Tuning. It enumerates as a HID device without external crystal, runs the Microchip MCHPFSUSB stack on the 16 MIPS PIC18 core, and the 32 KB Flash accommodates HID report descriptors plus application code. The 25 I/O pins scan key matrices or capacitive touch buttons directly. Sleep current of 20 nA in XLP Sleep mode extends battery life in wireless USB dongles, making it a strong fit for low-cost consumer input devices.
Recommended
USB-to-UART Bridge / Virtual COM Port
The PIC18LF25K50-I/SS operates as a USB CDC class device, presenting a virtual COM port to a host PC while exposing a UART to the embedded system. The integrated USB transceiver eliminates the FTDI-style external chip, the 48 MHz internal oscillator with Active Clock Tuning meets USB timing without a crystal, and the 2 KB RAM buffers UART and USB packets comfortably up to 921,600 bps. The 1.8 V to 3.6 V supply range powers the device from the USB 3.3 V rail directly. Compared with discrete USB-to-UART bridges, this part is a single-chip solution that can also run application firmware alongside the bridge function.
Recommended
Battery-Powered Sensor Logger with USB Recharge
The PIC18LF25K50-I/SS excels in battery-powered sensor loggers because of its nanoWatt XLP Sleep mode at 20 nA typical, 1.8 V to 3.6 V operation that runs directly from a single Li-ion cell, and integrated USB that lets the logger recharge or offload data over the same port. The 10-bit ADC with up to 14 channels interfaces directly with analog sensors (temperature, pressure, gas), while the 256-byte EEPROM stores calibration constants across power cycles. The 32 KB Flash holds time-stamped log firmware with USB CDC output, eliminating an external SD card for short-duration field studies.
Recommended
Low-Speed USB Audio Class Device (Headset Adapter)
The PIC18LF25K50-I/SS implements a USB Audio Class 1.0 device (full-speed, mono 16 kHz) for low-cost headset adapters or intercom endpoints. The integrated USB SIE handles isochronous endpoint transfers, the 48 MHz core runs the USB polling plus audio interrupt at 1 ms SOF, and the on-chip 10-bit PWM can drive a Class-D audio output stage directly for low-power speaker playback. The XLP Sleep mode is used between audio frames, and the part runs from the USB 5 V rail without external regulation. Its small 28-SSOP footprint fits inside USB connector dongles.
Recommended
Industrial Data Acquisition over USB
The PIC18LF25K50-I/SS fits industrial data acquisition front-ends where 4-20 mA loop signals, thermocouples, or 0-10 V transducers need digitizing and forwarding over USB. The 14-channel 10-bit ADC samples at rates up to 100 ksps, the ECCP modules generate PWM for excitation, and the integrated USB streams the digitized data to a host PC at full-speed rates without compression. The -40C to +85C industrial temperature range suits factory floor enclosures, and the LF variant supports 3.3 V sensor rails natively. The same firmware can run on the PIC18LF25K50-E/SS for +125C extended-temperature deployments.
Recommended
Consumer Electronics with USB Charging Port
The PIC18LF25K50-I/SS serves as the USB device controller in consumer electronics such as toys, e-cigarettes, or fitness bands where a micro-USB port both charges the battery and provides a data interface. The USB module negotiates with standard chargers, the ADC monitors battery voltage, and the 25 I/O pins drive LEDs, buttons, and haptic motors. Its 1.8 V to 3.6 V supply matches single-cell Li-ion directly, and the 32 KB Flash holds both USB CDC firmware and product behavior code. Compared with discrete USB controllers, the integrated PIC approach reduces BOM by one IC plus the external crystal.
Recommended
USB-Connected Programmer / Debug Probe Bridge
The PIC18LF25K50-I/SS can host a USB-to-ICSP bridge for legacy or low-cost programming adapters. The integrated USB device stack and 16 MIPS core emulate an ICSP master at 5 MHz, the SSOP-28 package exposes GPIO suitable for 6-wire ICSP, and the 32 KB Flash fits the bridge firmware plus bootloader. It also acts as a JTAG-to-USB translator for boards without native USB. Engineers reusing the PIC18 platform benefit from Microchip's standard USB stack, and the 3.3 V supply matches target boards without level shifters.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF25K50-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K50-I/SS | PIC18LF25K50-I/SO | PIC18LF25K50-E/SS | PIC18LF24K50-I/SS | PIC18LF25K42-I/SS |
|---|---|---|---|---|---|---|
| Package | 28-SSOP | 28-SSOP (same) | 28-SOP (wider body, electrical drop-in) | 28-SSOP (same) | 28-SSOP (same) | 28-SSOP (same) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 16 KB | 32 KB |
| Operating Voltage Range | 1.8 V to 3.6 V | 2.3 V to 5.5 V | 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 |
| Max CPU Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 64 MHz |
| RAM | 2 KB | 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 | USB 2.0 FS Device (newer SIE) |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +125C (extended) | -40C to +85C | -40C to +85C |
| Unit Price (qty 1) | $3.20 | ~$3.10 | ~$3.40 | ~$4.50 (extended temp) | ~$2.95 | ~$2.80 |
Key Differentiators
- Lower operating voltage range than the F variant (vs PIC18F25K50-I/SS)
- More Flash memory than the K24 sibling (vs PIC18LF24K50-I/SS)
- Mature USB stack and reference firmware (vs PIC18LF25K42-I/SS)
- Extended-temperature drop-in option (vs PIC18LF25K50-E/SS)
- More I/O pins than smaller-footprint siblings (vs PIC18LF13K50-I/SS)
Design Notes
The PIC18LF25K50-I/SS requires a 0.1 uF ceramic decoupling capacitor placed within 5 mm of the VDD pin (pin 21), plus a 10 uF bulk capacitor if the supply is the USB 3.3 V rail. The VUSB pin (pin 13) is the internal 3.3V LDO output and MUST be bypassed with 220 nF to VSS; this is the supply for the USB transceiver and is critical for USB-IF compliance. Estimated: at 48 MHz active and 3.3 V supply, the typical operating current is approximately 9 mA, while XLP Sleep drops to 20 nA - both from Microchip datasheet DS39984 typical curves.
Do not connect D+ and D- directly to the USB connector without the required 27 ohm series termination resistors and ESD protection (such as USBLC6-2). The internal transceiver expects these external components to meet USB 2.0 signal integrity and IEC 61000-4-2 ESD levels. Also note: pin 1 (RA0/VCAP) doubles as the core voltage decoupling pin and requires a 1 uF capacitor to VSS; omitting it causes erratic operation or program memory corruption. The VUSB pin must NEVER be driven externally.
For the 28-SSOP package, route the USB D+ and D- traces as a 90 ohm differential pair with matched length to within 150 mil, and keep them short (under 25 mm) to avoid signal integrity issues. Place the decoupling and VUSB capacitors on the same layer as the IC with vias to the ground plane kept away from the D+/D- pair. Avoid running noisy switching signals (PWM, ECCP outputs) under the SSOP footprint; the SSOP-28 has limited thermal dissipation so a copper pour on both top and bottom under the exposed leads reduces junction temperature rise during sustained 48 MHz operation.
At full 48 MHz operation from a 3.3 V supply, the PIC18LF25K50-I/SS dissipates approximately 30 mW, well within the SSOP-28 thermal rating of approximately 400 mW. The device has no exposed thermal pad, so the copper pour under the SSOP body and on the bottom layer is the primary heat dissipation path. For sealed enclosures without airflow, verify that internal ambient stays below +70C to maintain margin to the +85C industrial limit. Per Microchip datasheet DS39984, the internal die temperature sensor is not exposed externally, so designers must use ambient plus thermal derating.
When using Active Clock Tuning from the USB host (the recommended mode for low-cost USB designs), connect the D+/D- lines directly to the IC and ensure the USB hub or host PC is the only reference for clock accuracy. If a crystal is added to OSC1/OSC2 as backup, route it close to the IC and keep it away from the USB traces. The ICSP pins (RB6/ICSPCLK at pin 28 and RB7/ICSPDAT, which is not bonded on SSOP-28 but is accessible via test pads) should be brought out to test points for production programming; do not share these pins with high-current loads.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified; for automotive, evaluate PIC18F25K50-I/SS in the same family or use PIC18LF25K50-E/SS for extended temperature. USB-IF compliant transceiver (Test ID pending verification against the certified parts list).
