PIC18F2550T-I/SO - 8-bit 48MHz USB MCU 32KB Flash | Microchip
MPN: PIC18F2550T-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.41 | $8.41 |
| 10 | $7.57 | $75.70 |
| 100 | $6.36 | $636.00 |
| 500 | $5.41 | $2,705.00 |
| 1,000 | $4.83 | $4,830.00 |
PIC18F2550T-I/SO Overview
A microcontroller (MCU) is a single-chip computer that combines a CPU, memory (Flash/RAM/EEPROM), and programmable peripherals. The PIC18F family belongs to Microchip's enhanced 8-bit architecture with a 16-bit instruction word and an 8-bit data path, positioning it between simple 8-bit MCUs and 16/32-bit parts in terms of performance and cost. Within the PIC hierarchy: PIC18F -> enhanced 8-bit PIC -> 8-bit MCU -> microcontroller -> embedded controller -> semiconductor. The integrated USB 2.0 Full-Speed transceiver is a key differentiator, eliminating the need for an external USB PHY and reducing BOM cost for USB peripherals.
Key specifications include 24 digital I/O pins, 10-bit ADC with up to 10 channels, two 8-bit and three 16-bit timers, two analog comparators, and nanoWatt power management with multiple sleep modes. The device supports ICSP (In-Circuit Serial Programming) and ICD (In-Circuit Debug) via two pins, enabling field firmware updates and real-time debug. It is specified over the -40C to +85C industrial temperature range, making it suitable for consumer, industrial, and embedded USB applications.
Typical applications include USB human-interface devices (HID keyboards, mice, game controllers), USB-to-serial bridges, USB sensors and data loggers, low-cost USB dongles, and embedded learning platforms. The wide SOIC footprint allows hand-soldering and breadboard-friendly prototyping, which is why this part remains popular in education and hobby projects. The T suffix denotes Tape and Reel packaging for high-volume assembly.
When designing with this part, pay attention to the USB D+/D- pin routing (impedance-controlled 90 ohm differential) and the VUSB pin filtering (capacitor to ground per datasheet). The internal oscillator may be sufficient for low-USB-timing-margin designs; otherwise use a 48MHz crystal for USB Full-Speed compliance.
Drop-in alternatives for PIC18F2550T-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 PIC18F2550T-I/SO (same form factor and footprint) — differing in ADC, Package, Serial Interfaces, Timers, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2550-I/SO
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC18F2455-I/SO
✅ Drop-In✓ In Stock
$6.4 / Unit
View Datasheet →PIC18F2550-I/SP
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC18F4550-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F2550T-I/SO Maximum Ratings & Electrical Characteristics
| Architecture | PIC18F, 8-bit RISC |
| Core Size | 8-bit |
| Maximum Clock Frequency | 48 MHz |
| Program Memory (Flash) | 32 KB (16K x 16) |
| RAM | 2 KB |
| Data EEPROM | 256 bytes |
| Supply Voltage | 2.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Digital I/O Pins | 24 |
| ADC | 10-bit, up to 10 channels |
| Timers | 2 x 8-bit, 3 x 16-bit |
| USB | USB 2.0 Full-Speed (12 Mbit/s), integrated transceiver |
| Serial Interfaces | FS-USB, I2C, SPI (up to 10 Mbit/s), EUSART (LIN-capable) |
| Analog Comparators | 2 |
| Package | 28-SOIC (0.295 in / 7.50 mm wide body) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T suffix) |
| RoHS Status | Compliant |
| Programming/Debug | ICSP, ICD via 2 pins |
PIC18F2550T-I/SO Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear (reset) input or digital input only on RE3 |
| Pin 2 | RA0/AN0 — Digital I/O / analog input channel 0 |
| Pin 3 | RA1/AN1 — Digital I/O / analog input channel 1 |
| Pin 4 | RA2/AN2/VREF- — Digital I/O / analog input channel 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — Digital I/O / analog input channel 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — Digital I/O / analog input channel 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKI — Crystal oscillator input / external clock input |
| Pin 10 | OSC2/CLKO — Crystal oscillator output / clock output |
| Pin 11 | RC0/T1OSO/T1CKI — Digital I/O / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — Digital I/O / Timer1 oscillator input / Capture/Compare/PWM 2 |
| Pin 13 | RC2/CCP1 — Digital I/O / Capture/Compare/PWM 1 |
| Pin 14 | VUSB — Internal USB 3.3V regulator output (decoupling cap to VSS) |
| Pin 15 | RC4/D-/VM — Digital I/O / USB D- data line / external USB transceiver VM input |
| Pin 16 | RC5/D+/VP — Digital I/O / USB D+ data line / external USB transceiver VP input |
| Pin 17 | RC6/TX/CK — Digital I/O / EUSART TX / EUSART synchronous clock |
| Pin 18 | RC7/RX/DT — Digital I/O / EUSART RX / EUSART synchronous data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage (2.0V to 5.5V) |
| Pin 21 | RB0/AN12/INT0 — Digital I/O / analog input channel 12 / external interrupt 0 |
| Pin 22 | RB1/AN10/INT1 — Digital I/O / analog input channel 10 / external interrupt 1 |
| Pin 23 | RB2/AN8/INT2 — Digital I/O / analog input channel 8 / external interrupt 2 |
| Pin 24 | RB3/AN9/CCP2 — Digital I/O / analog input channel 9 / Capture/Compare/PWM 2 |
| Pin 25 | RB4/AN11 — Digital I/O / analog input channel 11 |
| Pin 26 | RB5/AN13 — Digital I/O / analog input channel 13 |
| Pin 27 | RB6/ICSP/PGC — Digital I/O / ICSP clock / in-circuit debug clock |
| Pin 28 | RB7/ICSP/PGD — Digital I/O / ICSP data / in-circuit debug data |
Typical Applications
PIC18F2550T-I/SO is suitable for 7 applications: USB HID Keyboard / Mouse, USB-to-Serial Bridge (CDC), USB Data Logger / Sensor Interface, USB Dongle / Programmer, Embedded Learning / Hobby Platform, Custom USB Class Device (Vendor-Specific), Industrial USB Sensor / Test Equipment.
USB HID Keyboard / Mouse
The PIC18F2550T-I/SO's integrated USB 2.0 Full-Speed transceiver and 48MHz/12 MIPS core are well-matched to USB HID keyboard and mouse designs, where it acts as the device controller and reports scan-matrix events over HID boot protocol. The 32KB Flash accommodates Microchip's MCHPFSUSB HID stack plus application code, while the 2KB RAM buffers HID reports without DMA. Industrial -40C to +85C operation supports consumer and embedded keyboards; the 28-SOIC wide-body package is hand-solderable for prototypes and tape-and-reel compatible for SMT production. Firmware uses the free USB stack from Microchip, with descriptors generated via the HID descriptor tool. Power draw is dominated by the USB pull-up (~1.5kohm to 3.3V) and core quiescent current.
Recommended
USB-to-Serial Bridge (CDC)
In USB-to-serial bridge designs the PIC18F2550T-I/SO runs the CDC (Communications Device Class) firmware to present itself as a virtual COM port to a host PC, eliminating the need for a dedicated USB-UART IC. The integrated USB Full-Speed transceiver handles physical layer, while the EUSART peripheral drives the external UART side up to LIN-capable baud rates. The 48MHz core and 12 MIPS throughput allow full-speed USB bulk transfers without bottlenecking; 32KB Flash fits CDC stack plus custom protocol glue. Operating from 2.0V-5.5V, the device can also power a 3.3V or 5V target UART rail. The 28-SOIC package fits in compact dongle form factors with a mini-USB or micro-USB connector.
Recommended
USB Data Logger / Sensor Interface
The PIC18F2550T-I/SO's 10-bit ADC (up to 10 channels), 2KB RAM buffer, and integrated USB 2.0 Full-Speed make it a natural fit for low-rate USB data loggers streaming sensor samples to a host PC. The 48MHz CPU handles ADC sampling at the Nyquist rate for typical temperature, pressure, and voltage sensor channels, with the USB bulk endpoint pushing data at up to 12 Mbit/s theoretical (typically 1 MB/s practical). The 256-byte EEPROM provides non-volatile configuration storage. The -40C to +85C industrial temperature range suits field deployment in industrial sensor pods. Power can be drawn from the USB VBUS rail directly via the internal 3.3V regulator.
Recommended
USB Dongle / Programmer
The PIC18F2550T-I/SO's 32KB Flash and USB Full-Speed interface make it a classic choice for USB dongles, including the well-known Microchip PICKit2-compatible programmers and custom ISP tools. The ICSP/ICD support allows it to act as a host programmer for downstream PIC microcontrollers via two programming pins plus VPP/VCC rails. Operating from USB VBUS power simplifies dongle power architecture. The 28-SOIC wide-body package has a strong pin pitch (1.27mm) that simplifies hand-soldering during dongle prototypes. The T suffix tape-and-reel packaging supports automated SMT for dongle production runs.
Recommended
Embedded Learning / Hobby Platform
The PIC18F2550T-I/SO is widely used in university embedded systems courses, hobby robotics, and DIY USB projects because of its USB Full-Speed capability in a hand-solderable 28-SOIC wide-body package. The PICKit2/PICKit3 programmer ecosystem provides low-cost in-circuit debugging, and free MPLAB X IDE with the XC8 compiler supports Windows, macOS, and Linux development. The 32KB Flash accommodates substantial student projects while remaining affordable at under $9 per unit. Industrial temperature range is forgiving in lab environments. The PIC18 instruction set is well-documented in academic textbooks, and the integrated USB peripheral simplifies USB class projects for students.
Recommended
Custom USB Class Device (Vendor-Specific)
In custom USB class applications the PIC18F2550T-I/SO acts as a vendor-specific USB device communicating with a host driver over bulk or interrupt endpoints. Microchip's MCHPFSUSB stack supports vendor-specific class devices with custom drivers on Windows, macOS, and Linux hosts. The 48MHz core handles USB protocol overhead with margin, and 32KB Flash fits vendor stack plus application logic. The 2KB RAM is sufficient for bulk transfer buffers up to 64 bytes per endpoint (USB Full-Speed maximum). The industrial temperature range supports industrial PC peripherals and test equipment.
Recommended
Industrial USB Sensor / Test Equipment
The PIC18F2550T-I/SO's industrial -40C to +85C temperature range and USB Full-Speed interface support industrial USB-connected test equipment, USB-based sensor pods, and lab instrumentation. The integrated USB transceiver eliminates external PHY components required by competing MCUs, reducing BOM and assembly cost. The 10-bit ADC is suitable for general-purpose measurement; the 2 analog comparators enable threshold detection. The 28-SOIC package withstands industrial conformal coating processes. EUSART with LIN capability extends the part to industrial sensor networks when USB is not the primary interface.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F2550T-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2550-I/SO | PIC18F2455-I/SO | PIC18F2550-I/SP | PIC18F4550-I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (7.50mm wide) | 28-SOIC (7.50mm wide) - same | 28-SOIC (7.50mm wide) - same | 28-SOIC (7.50mm wide) - same | 40-PDIP (different pin count) |
| Flash Program Memory | 32 KB | 32 KB | 24 KB (-25%) | 32 KB | 32 KB |
| RAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| Max Clock Frequency | 48 MHz | 48 MHz | 48 MHz | 48 MHz | 48 MHz |
| USB | USB 2.0 Full-Speed, integrated | USB 2.0 Full-Speed, integrated | USB 2.0 Full-Speed, integrated | USB 2.0 Full-Speed, integrated | USB 2.0 Full-Speed, integrated |
| I/O Pins | 24 | 24 | 24 | 24 | 35 (40-pin) |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Price Tier (qty 1) | $8.41 | $7.50-$8.50 (similar) | $7.00-$8.00 (lower) | $8.50-$9.50 (slightly higher, PDIP) | $9.00-$10.00 (higher, more I/O) |
Key Differentiators
- Integrated USB 2.0 Full-Speed transceiver eliminates external USB PHY IC (vs PIC18F2455-I/SO)
- 32KB Flash in compact 28-SOIC package (vs PIC18F2455-I/SO)
- Tape and Reel packaging for high-volume SMT assembly (vs PIC18F2550-I/SP)
- More compact 28-pin form factor than 40-pin PIC18F4550 (vs PIC18F4550-I/P)
Design Notes
USB D+ (RC5) and D- (RC4) traces must be routed as a 90 ohm differential pair with length matching within 150 mil per USB Full-Speed spec. Keep the VUSB decoupling capacitor within 2mm of pin 14 with a short trace to ground (pin 8 or 19) to suppress USB 3.3V regulator noise. Avoid routing noisy switching signals (PWM, SPI) adjacent to the D+/D- pair. A common-mode choke on D+/D- is optional but recommended for industrial environments with EMI. Per Microchip PIC18F2455/2550/4455/4550 datasheet, the 28-SOIC wide-body package has improved thermal dissipation versus narrow-body SOIC - relevant when the part drives USB bus power.
The PIC18F2550T-I/SO features nanoWatt power management with multiple idle modes (Idle, Sleep) that drop current to microampere levels. For USB applications, suspend current must stay below 2.5mA per USB 2.0 spec; ensure the firmware properly enters Sleep mode when USB is suspended. The internal 3.3V USB regulator on VUSB pin requires a 220nF decoupling capacitor per datasheet - omitting it causes USB enumeration failures. For bus-powered designs, ensure VDD does not exceed 5.5V (USB VBUS is typically 5.0V +/- 5%).
Common pitfalls when designing with the PIC18F2550T-I/SO: (1) Forgetting the VUSB decoupling capacitor causes USB enumeration failure - always include 220nF X7R ceramic. (2) Using a 20MHz crystal instead of 48MHz causes USB timing errors; 48MHz is required for USB Full-Speed operation with the PLL. (3) Programming via ICSP requires the PGD/PGC pins (RB7/RB6) to be free of strong pull-ups that interfere with the programmer. (4) The internal oscillator may be insufficient for USB compliance; use a 48MHz crystal for production designs per Microchip recommendations. (5) Configuration bits must be set correctly for USB PLL enable.
For reliable USB Full-Speed operation, place a 220nF X7R ceramic decoupling capacitor on VDD (pin 20) within 5mm of the pin, and another 220nF on VUSB (pin 14) per datasheet. Ground pins 8 and 19 should connect to a common ground plane via short traces. Crystal traces (OSC1/OSC2) should be short, symmetric, and guarded by ground plane to minimize EMI. The 28-SOIC wide-body package (7.50mm body width) uses a 1.27mm pin pitch which is hand-solderable and breadboard-friendly.
USB signal integrity on the PIC18F2550T-I/SO requires careful PCB layout. The D+ and D- lines must be 90 ohm differential impedance controlled, with length matching within 150 mil. Avoid stubs on D+/D- lines. Place the common-mode choke (optional) within 10mm of the USB connector. Keep the USB lines away from clock signals and switching regulators. The internal USB pull-up resistor (software-selectable on D+) should not require external 1.5kohm pull-up for Full-Speed operation per USB spec.
Compliance Information
RoHS compliant per Microchip product page. Industrial temperature range -40C to +85C. Not AEC-Q100 qualified (industrial/consumer grade).
