PIC18LF2221-I/SS - 40MHz 8-bit MCU, 4KB Flash, 28-SSOP | Microchip
MPN: PIC18LF2221-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.84 | $28.40 |
| 100 | $2.51 | $251.00 |
| 500 | $2.27 | $1,135.00 |
| 1,000 | $2.02 | $2,020.00 |
PIC18LF2221-I/SS Overview
Background: An 8-bit microcontroller (MCU) is a small, self-contained computer on a single IC that integrates a CPU, non-volatile program memory (Flash), working RAM, data EEPROM, and peripherals such as timers, ADC, and serial ports. Within the broader taxonomy, an MCU belongs to microcontrollers -> embedded processors -> integrated circuits -> semiconductors. The PIC18 family uses Microchip's enhanced Harvard RISC architecture with 77 single-word instructions and an 8-level hardware stack, offering deterministic interrupt response and a low learning curve for new firmware developers.
The PIC18LF2221-I/SS exposes up to 25 digital I/O pins, a 10-bit ADC with multiple channels, enhanced PWM/ECCP, USART, MSSP (SPI/I2C), and flexible oscillator options including a 31 kHz internal low-power oscillator. The combination of nanoWatt power management, low-voltage operation down to 2.0 V, and a generous peripheral set makes it well suited to battery-powered and space-constrained designs.
Typical applications include consumer appliances, sensor signal conditioning, low-cost motor control, USB/HID human-interface devices, industrial telemetry, and small-scale IoT nodes. The wide voltage range simplifies designs that must accept both 2xAA alkaline and 3.3 V regulated rails.
When designing with this part, remember to budget for the ICSP/ICD pins and add a decoupling capacitor pair (100 nF + bulk) close to VDD/AVDD/VSS. Pull MCLRE high or low per the application to select the correct reset mode. The 'I' suffix indicates the industrial -40C to +85C temperature grade.
This page synthesizes verified distributor stock, parametric comparisons against PIC18F-family alternatives, and practical design notes not collected in any single datasheet revision.
Drop-in alternatives for PIC18LF2221-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 PIC18LF2221-I/SS (same form factor and footprint) — differing in Package, ADC, I/O Pins, Operating Temperature, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2221-I/SS
✅ Drop-In✓ In Stock
$2.79 / Unit
View Datasheet →PIC18LF2221-I/SP
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →PIC18LF2221-I/ML
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC18LF2220-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF1320T-I/SS
✅ Drop-In✓ In Stock
$3.65 / Unit
View Datasheet →PIC18LF1220-I/SS
✅ Drop-In✓ In Stock
$0.81 / Unit
View Datasheet →PIC18LF2221-I/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 8-bit RISC |
| Program Memory (Flash) | 4 KB (2K x 16) |
| Data SRAM | 512 bytes |
| Data EEPROM | 256 bytes |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| I/O Pins | 25 |
| ADC | 10-bit, multiple channels |
| PWM / ECCP | Yes (Enhanced CCP) |
| USART | 1 |
| MSSP (SPI / I2C) | Yes |
| Timers | 8-bit and 16-bit timer modules |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | SSOP-28 (208 mil) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Instruction Set | 77 single-word instructions |
| Reset/Power Management | nanoWatt technology, internal 31 kHz oscillator |
PIC18LF2221-I/SS Pin Configuration
| Pin 1 | RA2/AN2/VREF- — PORTA bit 2 / Analog input 2 / negative voltage reference |
| Pin 2 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / positive voltage reference |
| Pin 3 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 4 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 5 | VSS — Ground reference |
| Pin 6 | OSC1/CLKI/RA7 — Oscillator input / external clock / PORTA bit 7 |
| Pin 7 | OSC2/CLKO/RA6 — Oscillator output / PORTA bit 6 |
| Pin 8 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock |
| Pin 9 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 10 | RC2/CCP1 — PORTC bit 2 / Enhanced CCP1 output |
| Pin 11 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 12 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 13 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 14 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 15 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 16 | VSS — Ground reference (second pin) |
| Pin 17 | VDD — Positive supply |
| Pin 18 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 19 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 20 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 21 | RB3/CCP2 — PORTB bit 3 / CCP2 alternate |
| Pin 22 | RB4 — PORTB bit 4 |
| Pin 23 | RB5/PGM — PORTB bit 5 / LVP programming |
| Pin 24 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 25 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 26 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 27 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 28 | MCLR/VPP/RA5 — Reset (active low) / programming voltage / PORTA bit 5 alternate |
Typical Applications
PIC18LF2221-I/SS is suitable for 6 applications: Consumer Appliance Control, Battery-Powered Sensor Node, USB HID / Human-Interface Device, Low-Cost Motor Control (DC / Stepper), Industrial Telemetry / Remote Monitoring, Educational / Maker / Hobby Electronics.
Consumer Appliance Control
The PIC18LF2221-I/SS is a natural fit for consumer appliances (coffee makers, washing machines, microwaves) because its 2.0 V-5.5 V VDD range handles both rectified 5 V rails and 3.3 V sensor rails without level shifting. The 40 MHz core executes PID-style control loops in well under 1 ms per iteration, while the 10-bit ADC reads temperature, pressure, and current-sensor outputs simultaneously. With 25 I/O pins, the MCU can drive triac/relay drivers, keypads, and seven-segment or character LCDs directly, and the on-chip ECCP generates the precise zero-crossing switching waveforms that dimmer and induction-cooktop stages require. Industrial -40C to +85C operation covers behind-the-panel heat-rise conditions. The 256-byte EEPROM stores user preferences and last-state memory across power cycles, avoiding a separate non-volatile chip.
Recommended
Battery-Powered Sensor Node
For 2xAA alkaline or single-cell Li-ion sensor nodes, the PIC18LF2221-I/SS gives true 2.0 V operation, preserving usable capacity all the way to brownout. nanoWatt technology drops quiescent current to the microamp range in sleep, and the internal 31 kHz oscillator eliminates an external RTC chip. The PIC18 core wakes on interrupt, samples a thermistor or load-cell through the 10-bit ADC, and transmits the reading via USART or MSSP to an external radio. The 4 KB Flash accommodates small over-the-air update bootloaders, while 256 bytes of EEPROM holds calibration constants. SSOP-28 keeps the PCB under 10x10 mm for wearable or remote-telemetry form factors.
Recommended
USB HID / Human-Interface Device
The PIC18LF2221-I/SS handles USB HID class devices such as keyboards, mice, game controllers, and custom input peripherals when paired with an external USB transceiver or used with a software USB stack on PORTB. Its 10 MIPS throughput is more than enough for HID polling rates above 125 Hz, and the USART can drive a Bluetooth/Wi-Fi co-processor for wireless HID products. The 25 I/O pins read large matrix keypads (8x8) directly, and ECCP generates the PWM signal driving vibration motors or RGB backlights. Industrial temperature grade suits automotive cabin environments, and the LF voltage range lets a single design run from either a USB 5 V rail or a 3.3 V regulator downstream of a switching converter.
Recommended
Low-Cost Motor Control (DC / Stepper)
For small brushed DC and unipolar/bipolar stepper drives, the PIC18LF2221-I/SS uses its ECCP module to generate precise PWM up to 40 MHz, while timers handle back-EMF and current sensing. The 10-bit ADC samples shunt-resistor voltage across H-bridges at high duty, and the 2.0 V minimum supply permits operation from a single Li-ion cell. With SSOP-28 the entire controller can fit under 100 mm square, leaving room for gate drivers and power stages on the same board. The 25 I/O pins drive enable, direction, brake, fault, and encoder signals simultaneously.
Recommended
Industrial Telemetry / Remote Monitoring
Industrial telemetry units (RTUs, remote sensors, process transmitters) lean on the PIC18LF2221-I/SS for its -40C to +85C industrial range, 4 KB Flash for MODBUS or proprietary protocol stacks, and 256-byte EEPROM for parameter storage. The 10-bit ADC captures 4-20 mA current loops through a sense resistor, and the USART talks to RS-485 transceivers. nanoWatt sleep modes extend battery life in field-mounted wireless units; the internal oscillator eliminates two external crystals. The 2.0 V-5.5 V range lets a single board accept either 24 V industrial loops (post-regulation) or 3.3 V coin-cell backup.
Recommended
Educational / Maker / Hobby Electronics
Hobbyists and students value the PIC18LF2221-I/SS for its MPLAB X IDE support, free XC8 compiler, and ICD/ICSP programming that lets a single tool both debug and burn Flash. The 28-pin SSOP package breaks out 25 I/O lines on a 0.65 mm pitch that hobbyists can hand-solder with fine-tip irons. Peripherals (ADC, PWM, USART, I2C/SPI) cover nearly every introductory project from blinking LEDs to I2C sensors. The LF voltage range tolerates loose benchtop wiring mistakes that pull rails below 5 V, and the 40 MHz headroom runs small RTOS kernels for advanced learners.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2221-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2221-I/SS | PIC18LF2221-I/SP | PIC18LF2221-I/ML | PIC18LF2220-I/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SSOP-28 | SSOP-28 (same) | SPDIP-28 (through-hole) | QFN-28 | SSOP-28 (same) |
| Core / Architecture | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC18 8-bit RISC | PIC18 8-bit RISC |
| Program Memory (Flash) | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB |
| Data SRAM | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 512 bytes |
| Data EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Maximum CPU Speed | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) |
| Supply Voltage | 2.0 V - 5.5 V | 4.2 V - 5.5 V (5 V only) | 2.0 V - 5.5 V | 2.0 V - 5.5 V | 2.0 V - 5.5 V |
| I/O Pins | 25 | 25 | 25 | 25 | 25 |
| ECCP / Enhanced PWM | Yes | Yes | Yes | Yes | No (smaller pinout) |
Key Differentiators
- Wide 2.0 V-5.5 V VDD range supports battery-powered and 3.3 V designs (vs PIC18F2221-I/SS)
- Surface-mount SSOP-28 footprint with 208-mil body (vs PIC18LF2221-I/SP)
- Enhanced CCP module with full-bridge PWM support (vs PIC18LF2220-I/SS)
- Industrial -40C to +85C temperature range standard (vs PIC18LF1320T-I/SS)
Design Notes
Estimated: At 40 MHz and 5 V VDD, the PIC18LF2221-I/SS core draws approximately 11 mA per Microchip datasheet DC characteristics. For 3.3 V operation, the figure drops to roughly 5-6 mA. Add a 100 nF ceramic decoupling cap directly across VDD/VSS (within 5 mm of the pins), plus a 10 uF bulk cap on the same rail. For noise-sensitive analog reads, a separate AVDD pin should be tied through a ferrite bead or small resistor to VDD.
Always configure CONFIG3H.LVP correctly: enabling low-voltage programming on RB5/PGM makes RB5 unavailable as general I/O, while disabling LVP frees RB5 but requires 12 V on MCLR for ICSP. The MCLR pin must be pulled high through a 10 kohm resistor; leaving it floating causes random resets. Avoid using RA0-RA3 as digital inputs when VREF+ is tied to VDD - the input buffer can latch up at VDD-0.3 V or above.
Keep the 28-pin SSOP trace length for the oscillator pins (OSC1/OSC2) under 10 mm and surround them with a ground guard ring to reduce EMI susceptibility. Place the ICSP connector footprint (PGC/PGD/MCLR/VSS/VDD) on the board edge for programming access. For QFN variants (PIC18LF2221-I/ML), connect the central thermal/exposed pad to VSS for mechanical and thermal relief; floating it is a common defect.
When driving capacitive loads from PWM outputs, place a 100 ohm series resistor within 5 mm of the pin to slow edges and reduce ringing. For I2C lines (RC3/RC4), use 4.7 kohm pull-ups at 100 kHz and 2.2 kohm at 400 kHz; pull-ups above 50 mm of trace should be checked for signal integrity with an oscilloscope. USART lines benefit from a 100 ohm series damping resistor for cable lengths above 200 mm.
Compliance Information
RoHS and REACH compliance confirmed per Microchip product page and distributor listings. No AEC-Q100 variant in this family - this is industrial-grade only. Halogen-free status not specified in the available data.
