PIC18LF2550T-I/SO - 48MHz 8-bit USB MCU 32KB Flash 28-SOIC | Microchip
MPN: PIC18LF2550T-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.42 | $7.42 |
| 10 | $6.78 | $67.80 |
| 100 | $6.14 | $614.00 |
| 500 | $5.62 | $2,810.00 |
| 1,000 | $5.1 | $5,100.00 |
PIC18LF2550T-I/SO Overview
A PIC18F-series microcontroller is a member of Microchip's enhanced 8-bit RISC architecture family, combining a Harvard bus with a rich peripheral set including USB, I2C, SPI, EUSART (LIN-capable), multiple timers, ADC, and nanoWatt power management. PIC MCUs sit at the top of the 8-bit hierarchy - PIC -> PIC18F family -> PIC18F2550 sub-family - and serve as a low-cost, deterministic alternative to 32-bit MCUs in USB-enabled embedded applications. The integrated USB 2.0 Full-Speed transceiver eliminates the need for an external PHY, simplifying board design.
Key features include 48MHz maximum CPU clock (12 MIPS), hardware Full-Speed USB 2.0 transceiver, 24 digital I/O pins, a 10-bit ADC with up to 13 channels, two 8-bit and three 16-bit timers, nanoWatt power-saving modes, and an internal oscillator. The wide 2.0V-5.5V operating range allows single-cell Li-ion or regulated 5V supply designs with the same firmware.
The architecture combines an enhanced 16-bit instruction set with 8-bit data path, multi-vector interrupts with hardware context save, C-compiler-friendly orthogonal design, and 32-level hardware stack. The integrated USB SIE (Serial Interface Engine) handles packet framing, CRC, and endpoint management in hardware, leaving CPU bandwidth for application code.
Typical applications include low-cost USB peripherals (HID, CDC, custom-class devices), sensor interfaces and instrumentation, USB-to-UART bridges, consumer electronics, industrial control nodes, and educational/development boards. The wide voltage range and nanoWatt modes also make it suitable for battery-powered edge devices.
When designing with this part, ensure the VUSB pin is supplied with a stable 3.3V for the internal USB transceiver, and follow Microchip's USB hardware design guidelines for PCB layout. Configure the oscillator mode correctly for the chosen clock source - the internal oscillator is suitable for most non-USB applications; USB Full-Speed requires a 48MHz clock derived from a 20MHz crystal or the internal PLL.
This page synthesizes distributor pricing, drop-in alternatives within the same SOIC-28 footprint, and practical USB design notes not found in the bare datasheet.
Drop-in alternatives for PIC18LF2550T-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 PIC18LF2550T-I/SO (same form factor and footprint) — differing in Package, Serial Interfaces, Core Architecture, I/O Pins, USB.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF2550-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2455T-I/SO
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC18F2550T-I/SO
✅ Drop-In✓ In Stock
$4.83 / Unit
View Datasheet →PIC18LF2550-I/SP
✅ Drop-In✓ In Stock
$4.55 / Unit
View Datasheet →PIC18LF24K50T-I/SO
✅ Drop-In✓ In Stock
$2.95 / Unit
View Datasheet →PIC18LF2550T-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F Enhanced 8-bit RISC (Harvard) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| RAM Size | 2 KB (2K x 8) |
| EEPROM Size | 256 bytes |
| Maximum CPU Clock | 48 MHz (12 MIPS) |
| Operating Voltage Range | 2.0 V to 5.5 V |
| Number of I/O Pins | 24 |
| ADC | 10-bit, up to 13 channels |
| USB | USB 2.0 Full-Speed (12 Mbit/s) with on-chip transceiver |
| Serial Interfaces | USB, I2C, SPI (up to 10 Mbit/s), EUSART (LIN-capable) |
| Timers | 2 x 8-bit, 3 x 16-bit |
| Package | 28-pin SOIC (7.50 mm body width) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Packaging | Tape and Reel |
| RoHS Status | Compliant |
PIC18LF2550T-I/SO Pin Configuration
| Pin 1 | MCLR/VPP/RE3 — Master Clear / Programming voltage / digital-only RE3 |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2/VREF-/CVREF- — PORTA bit 2 / analog input 2 / DAC reference negative |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC positive reference |
| Pin 6 | RA4/T0CKI/C1OUT — PORTA bit 4 / Timer0 clock input / Comparator 1 output |
| Pin 7 | RA5/AN4/SS/HLVDIN/C2OUT — PORTA bit 5 / analog input 4 / SPI slave select / HV detect / Comparator 2 output |
| Pin 8 | RA6/OSC2/CLKO — PORTA bit 6 / crystal oscillator output / system clock output |
| Pin 9 | RA7/OSC1/CLKI — PORTA bit 7 / crystal oscillator input / external clock input |
| Pin 10 | GND — Ground |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 PWM/Capture |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM/Capture |
| Pin 14 | VUSB — USB internal 3.3 V transceiver supply |
| Pin 15 | RC4/D-/VM — PORTC bit 4 / USB D- / external USB monitor |
| Pin 16 | RC5/D+/VP — PORTC bit 5 / USB D+ / external USB monitor |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / EUSART TX / clock line |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / EUSART RX / data line |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive logic supply (2.0 V to 5.5 V) |
| Pin 21 | RB0/AN12/INT0 — PORTB bit 0 / analog input 12 / external interrupt 0 |
| Pin 22 | RB1/AN10/INT1 — PORTB bit 1 / analog input 10 / external interrupt 1 |
| Pin 23 | RB2/AN8/INT2 — PORTB bit 2 / analog input 8 / external interrupt 2 |
| Pin 24 | RB3/AN9/CCP2 — PORTB bit 3 / analog input 9 / CCP2 PWM/Capture |
| Pin 25 | RB4/AN11/KBI0 — PORTB bit 4 / analog input 11 / keyboard interrupt 0 |
| Pin 26 | RB5/KBI1/PGM — PORTB bit 5 / keyboard interrupt 1 / LVP programming |
| Pin 27 | RB6/KBI2/PGC — PORTB bit 6 / keyboard interrupt 2 / ICD clock |
| Pin 28 | RB7/KBI3/PGD — PORTB bit 7 / keyboard interrupt 3 / ICD data |
Typical Applications
PIC18LF2550T-I/SO is suitable for 6 applications: USB HID Peripherals, USB-to-UART Bridge, Industrial Sensor / Data-Logging Nodes, Consumer Electronics and Toys, Custom-USB Test and Measurement, USB-Connected Medical/Wellness Devices.
USB HID Peripherals
The PIC18LF2550T-I/SO is widely used in USB HID-class devices such as custom keyboards, mice, game controllers, and input emulators. The integrated Full-Speed USB 2.0 transceiver and SIE handle enumeration, endpoint management, and HID report descriptors entirely in hardware, eliminating external PHY cost. With 32 KB Flash, the part comfortably fits HID stacks plus application logic (key remapping, macro scripting, RGB control). The 48 MHz / 12 MIPS core sustains 1000 Hz polling with headroom for capacitive or matrix scanning. The 2.0-5.5 V supply allows direct battery or USB bus power; pair with a 3.3 V LDO on VUSB when running from a 5 V bus.
Recommended
USB-to-UART Bridge
A classic application for PIC18LF2550T-I/SO is a USB CDC-class bridge that presents a virtual COM port over USB and forwards bytes to a UART. With hardware USB and the integrated EUSART, this design needs only firmware - no external USB-to-serial ICs (FTDI, CP210x) are required, dramatically reducing BOM cost. The 48 MHz core sustains sustained 921600 bps bridging without bottleneck. The 256 B EEPROM is handy for storing bridge configuration (baud defaults, GPIO mapping). The wide 2.0-5.5 V supply allows the bridge to power 3.3 V or 5 V target boards from the USB bus directly.
Recommended
Industrial Sensor / Data-Logging Nodes
The PIC18LF2550T-I/SO serves well in remote sensor and data-logging nodes that upload via USB to a host PC for analysis. The 10-bit ADC (up to 13 channels) accepts analog signals from thermocouples, RTDs, strain gauges, or generic 0..5 V sensors with sample rates up to ~100 kS/s. The 2 KB SRAM buffers local measurement bursts before USB transfer; 32 KB Flash holds calibration tables and lightweight protocols. nanoWatt Sleep reduces quiescent current to microampere levels between samples, enabling multi-month battery life on a single cell when USB is unplugged.
Recommended
Consumer Electronics and Toys
Cost-sensitive consumer products, toys, and educational kits use PIC18LF2550T-I/SO for USB firmware-updateable microcontroller functions (LED control, motor drive via PWM, sound playback). Three 16-bit timers generate PWM for servo, motor speed, or LED dimming with hardware precision. The 24 GPIO directly drive multiplexed 7-segment or charlieplexed LED matrices. USB enables in-field firmware updates without an external programmer - a major user-experience win. The wide 2.0-5.5 V range allows a single design to ship as 3.3 V or 5 V variants with no BOM change.
Recommended
Custom-USB Test and Measurement
PIC18LF2550T-I/SO powers USB-based oscilloscope probes, logic analyzers, signal generators, and small bench instruments. The 48 MHz / 12 MIPS core runs capture/control loops in real time, while USB Full-Speed streams 12 Mbit/s of sample data to the host. The 10-bit ADC, plus external timing via the 16-bit CCP modules, enables basic mixed-signal capture. USB bus power removes the need for an external supply, and the small 28-SOIC footprint fits inside handheld probe housings. Adding a 3.3 V LDO for VUSB keeps USB signal compliance independent of the measurement analog supply.
Recommended
USB-Connected Medical/Wellness Devices
Low-cost USB-connected medical and wellness devices (pulse-oximeter hobby boards, peak-flow meters, posture sensors, fitness accessories) use PIC18LF2550T-I/SO for data acquisition and host communication. The 10-bit ADC samples photodiode or thermistor signals; the USB CDC class streams results to a host application for display and storage. The 32 KB Flash supports USB stacks plus lightweight signal processing (peak detection, smoothing). Note: this part is not AEC-Q100 qualified and is therefore not suitable for safety-critical medical applications, but it is appropriate for wellness and recreational health products.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2550T-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF2550-I/SO | PIC18LF2455T-I/SO | PIC18F2550T-I/SO | PIC18LF24K50T-I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (7.50 mm) | 28-SOIC (7.50 mm) - same | 28-SOIC (7.50 mm) - same | 28-SOIC (7.50 mm) - same | 28-SOIC (7.50 mm) - same |
| Program Memory (Flash) | 32 KB | 32 KB | 16 KB | 32 KB | 16 KB |
| RAM Size | 2 KB | 2 KB | 1 KB | 2 KB | 1.5 KB |
| Operating Voltage Range | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 1.8 V to 3.6 V |
| Maximum CPU Clock | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| USB | USB 2.0 FS integrated | USB 2.0 FS integrated | USB 2.0 FS integrated | USB 2.0 FS integrated | USB 2.0 FS integrated |
| Packaging Format | Tape and Reel | Tube | Tape and Reel | Tape and Reel | Tape and Reel |
| Approx Unit Price (qty 1000) | $5.10 | $5.05 | $4.80 | $5.30 | $3.95 |
Key Differentiators
- Wide 2.0 V to 5.5 V supply window enables single-cell Li-ion designs (vs PIC18F2550T-I/SO)
- 32 KB Flash / 2 KB RAM supports full USB stack + application (vs PIC18LF2455T-I/SO)
- Modern XLP nanoWatt power modes reduce sleep current (vs PIC18F2550T-I/SO)
Design Notes
Estimated: The PIC18LF2550T-I/SO requires two supply rails - VDD at 2.0 V to 5.5 V for the digital core, and a separate VUSB rail at 3.0 V to 3.6 V for the internal USB transceiver. When powering from 5 V USB VBUS, place a 100nF decoupling capacitor on VDD close to the pin and feed VUSB through a 3.3 V LDO (e.g., MCP1700 or MIC5205) with a 4.7uF bulk cap. When powering from a 3.3 V regulated source, tie VUSB directly to the same 3.3 V rail - never leave VUSB floating, the USB SIE will not enumerate without it.
Estimated: For USB Full-Speed signal integrity, route the D+ (RC5) and D- (RC4) lines as a 90-ohm differential pair with controlled impedance, keep matching within 0.15 mm length, and place the 27 pF to 33 pF series resistors on the connector side. Keep USB traces away from switching nodes, oscillator traces, and high-current paths. The VUSB decoupling cap must be within 5 mm of pin 14. Place a ferrite bead on the VBUS input to suppress bus noise from leaking into the analog supply.
Three common PIC18LF2550T-I/SO pitfalls: (1) Forgetting to configure the CONFIG registers for the chosen oscillator - USB requires HS-PLL mode with a 20 MHz crystal, while non-USB can use INTOSC; (2) Leaving ICPRT (internal USB regulator control) unset - many stacks fail without ICPRT=0 to disable the internal 3.3 V regulator when VUSB is supplied externally; (3) Selecting the wrong CPU divisor (CPUDIV=NO CLOCK) which silently disables the core. Always read back CONFIG1L and CONFIG1H after programming.
Estimated: The 28-SOIC land pattern should use 1.27 mm pitch pads (~0.5 mm wide x 1.5 mm long) with a generous thermal pad area below the part. For a hand-solderable prototype, add a 1.27 mm pitch DIP-adapter footprint or break out to 2.54 mm headers. Always include a 5 kohm pull-up on MCLR (pin 1) for clean reset, and 100 nF + 10 uF bulk caps on VDD close to the IC. If you do not use ICSP, leave PGC/PGD accessible via test pads to enable in-field firmware updates.
Compliance Information
RoHS and REACH compliant per Microchip product page; not AEC-Q100 qualified (consumer/industrial grade). Lead-free and halogen-free packaging. Not automotive-qualified - for automotive USB designs use PIC18F2550-I/SO with AEC-Q100 qualification or PIC18F4550 family with automotive grade.
