PIC18LF2221T-I/ML - 8-bit PIC MCU, 4KB Flash, 28-QFN | Microchip
MPN: PIC18LF2221T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.05 | $30.50 |
| 100 | $2.61 | $261.00 |
| 500 | $2.34 | $1,170.00 |
| 1,000 | $2.1 | $2,100.00 |
| 3,000 | $1.84 | $5,520.00 |
PIC18LF2221T-I/ML Overview
An 8-bit PIC microcontroller is a CISC-style, Harvard-architecture CMOS device that executes one instruction per instruction cycle (4 clock cycles) and uses a RISC-like, fixed-length instruction word to balance code density with deterministic timing. Within the broader taxonomy, the PIC18 sits between Microchip's baseline PIC10/12/16 family and the enhanced PIC24/dsPIC33 line: 8-bit core, but with linear memory, hardware multiply, and C-friendly extensions. PIC18F variants are the Flash-based mainstream; the 'LF' prefix designates the lower-voltage (2.0-5.5V) cell that replaces the older PIC18F 4.2-5.5V range for battery and energy-harvesting designs.
Key differentiating features of the PIC18LF2221 include the PIC18 instruction set (77 single-word instructions, hardware 8x8 multiply), a 10-bit ADC with up to 10 channels, two 8-bit timers plus one 16-bit timer, a Capture/Compare/PWM module, nanoWatt power management with multiple idle and sleep modes, an ICD-friendly in-circuit debug header, and an on-chip EEPROM emulation region in Flash. The integrated POR/BOR/WDT supervisory set reduces external component count.
The silicon uses a low-power CMOS process and a 4-phase internal clock derived from the user-selected oscillator block (HS, XT, LP, RC, internal 8 MHz/31 kHz), enabling either crystal-accurate timing or low-Iq operation down to a few microamps in sleep. Two priority levels of interrupt, a hardware stack, and a deterministic interrupt response make it well-suited to motor control and sensor sampling loops.
Typical applications include industrial sensor nodes, low-power handheld instruments, consumer appliances with HMI, USB/HID-free embedded controllers, and small motor or lighting controllers. It is well-matched wherever a deterministic 8-bit core, small Flash footprint, and 2-5.5V battery operation are needed.
A key design consideration when laying out the 28-QFN is the exposed thermal pad: it must be soldered to the board ground pour both for thermal dissipation and for the package's electrical ground reference, otherwise supply return impedance rises and analog readings drift. Decoupling should use a 100 nF X7R close to each VDD/VSS pair plus a bulk 4.7 uF on the main rail.
This page synthesizes Microchip datasheet specifications, current distributor pricing, drop-in QFN-28 alternatives from the same PIC18 family and competing vendors, and practical design notes that are not bundled on the manufacturer's product page.
Drop-in alternatives for PIC18LF2221T-I/ML — 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 PIC18LF2221T-I/ML (same form factor and footprint) — differing in Operating Temperature, Package, Communication, Timers, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF2221-I/ML
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.4 / Unit
View Datasheet →PIC18F2221-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2321-I/ML
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.1 / Unit
View Datasheet →PIC18F2321-I/ML
✅ Drop-In✓ In Stock
$3.17 / Unit
View Datasheet →PIC18LF2220-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF2221T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F (8-bit, Harvard, RISC-like) |
| Instruction Set Width | 16-bit (77 single-word instructions) |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Program Memory (Flash) | 4 KB (2K x 16) |
| Data SRAM | 512 bytes |
| Data EEPROM | 256 bytes (emulated in Flash per family) |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| I/O Pins | 16 |
| Timers | Two 8-bit + one 16-bit (TMR0/TMR1/TMR2) |
| Capture/Compare/PWM | 1 CCP module |
| ADC | 10-bit, up to 10 channels |
| Serial Interfaces | I2C (MSSP), SPI (MSSP), Enhanced USART |
| Operating Temperature | -40 C to +85 C (Industrial, 'I' suffix) |
| Package | 28-pin QFN (6x6 mm), 'ML' suffix |
| Mounting Type | Surface Mount |
| Packaging | Tape and Reel ('T' suffix) |
| RoHS Status | Compliant (LEAD FREE per digchip listing) |
| Oscillator Modes | HS, XT, LP, RC, internal 8 MHz, internal 31 kHz |
| Power-Saving Modes | nanoWatt: Sleep, Idle, multiple Run modes |
| Debug | In-Circuit Debug (ICD) via PGD/PGC pins |
PIC18LF2221T-I/ML Pin Configuration
| Pin 1 | RA2/AN2/VREF- — GPIO port A bit 2 / Analog input 2 / ADC negative reference |
| Pin 2 | RA3/AN3/VREF+ — GPIO port A bit 3 / Analog input 3 / ADC positive reference |
| Pin 3 | RA4/T0CKI/C1OUT — GPIO port A bit 4 / Timer0 clock input / Comparator 1 output |
| Pin 4 | RA5/AN4/SS/HLVDIN — GPIO port A bit 5 / Analog input 4 / SPI slave select / High-low voltage detect input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | OSC1/RA7 — External oscillator input / GPIO port A bit 7 |
| Pin 7 | OSC2/RA6 — External oscillator output / GPIO port A bit 6 |
| Pin 8 | RC0/T1OSO/T1CKI — GPIO port C bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 9 | RC1/T1OSI/CCP2 — GPIO port C bit 1 / Timer1 oscillator input / CCP2 |
| Pin 10 | RC2/CCP1 — GPIO port C bit 2 / CCP1 PWM module |
| Pin 11 | RC3/SCK/SCL — GPIO port C bit 3 / SPI clock / I2C clock |
| Pin 12 | RC4/SDI/SDA — GPIO port C bit 4 / SPI data in / I2C data |
| Pin 13 | RC5/SDO — GPIO port C bit 5 / SPI data out |
| Pin 14 | RC6/TX/CK — GPIO port C bit 6 / USART transmit / USART clock |
| Pin 15 | RC7/RX/DT — GPIO port C bit 7 / USART receive / USART data |
| Pin 16 | VSS — Ground reference (second VSS pin) |
| Pin 17 | VDD — Positive supply voltage 2.0V to 5.5V |
| Pin 18 | RB0/INT0/FLT0 — GPIO port B bit 0 / External interrupt 0 / PWM fault input |
| Pin 19 | RB1/INT1 — GPIO port B bit 1 / External interrupt 1 |
| Pin 20 | RB2/INT2 — GPIO port B bit 2 / External interrupt 2 |
| Pin 21 | RB3/CCP2 — GPIO port B bit 3 / CCP2 (alternate pin) |
| Pin 22 | RB4 — GPIO port B bit 4 |
| Pin 23 | RB5/PGM — GPIO port B bit 5 / LVP programming input |
| Pin 24 | RB6/PGC — GPIO port B bit 6 / ICD clock |
| Pin 25 | RB7/PGD — GPIO port B bit 7 / ICD data |
| Pin 26 | RA0/AN0 — GPIO port A bit 0 / Analog input 0 |
| Pin 27 | RA1/AN1 — GPIO port A bit 1 / Analog input 1 |
| Pin 28 | VDD — Positive supply voltage (second VDD pin) |
Typical Applications
PIC18LF2221T-I/ML is suitable for 6 applications: Battery-Powered Sensor Node, Industrial Control and Appliance HMI, Small Motor and Lighting Controller, Consumer Remote Control and Wireless Sensor, Smart Energy Meter and Sub-Metering, Educational and Maker Development Platform.
Battery-Powered Sensor Node
The PIC18LF2221T-I/ML is purpose-built for 2.0-5.5V battery-powered sensor nodes that need deterministic, low-Iq operation across long sleep intervals. Its 2.0V minimum VDD lets a 2x AA alkaline pack or end-of-life Li-ion cell still drive the MCU without a boost converter, while the nanoWatt sleep mode drops Iq into the microamp range. The 10-bit ADC with up to 10 channels handles temperature, humidity, and battery-monitor inputs without external muxing, and the 4 KB Flash is sufficient for periodic-sampling firmware with on-chip EEPROM emulation for nonvolatile log storage. Unlike a Cortex-M0+, the PIC18F core guarantees deterministic interrupt latency critical for sensor timing budgets. Place the QFN exposed pad on the board ground pour to keep the analog reference clean.
Recommended
Industrial Control and Appliance HMI
In industrial control panels and white-goods human-machine interfaces, the PIC18LF2221T-I/ML drives keypad scanning, LED multiplexing, and UART-to-master links within a 28-QFN footprint that survives the -40 to +85 C industrial temperature range. Its Enhanced USART handles RS-485 or RS-232 communication to a main controller, while the MSSP port runs an SPI or I2C keypad/display module. The 16 GPIOs are sufficient for a 4x4 keypad plus seven-segment or character-LCD drive. The CCP module generates PWM for backlight dimming or buzzer tones, and nanoWatt modes let the controller idle between user interactions to meet ENERGY STAR standby budgets. The LF cell supports 24V industrial bus rails stepped down to 5V or 3.3V without concern for 4.2V brown-out.
Recommended
Small Motor and Lighting Controller
The PIC18LF2221T-I/ML drives small brushed DC motors, stepper logic sequencers, and LED lighting strips using its 16-bit Timer1 plus the CCP PWM module. With one CCP channel it can produce center-aligned or edge-aligned PWM at programmable frequency and duty cycle, perfect for fan-speed control, solenoid PWM, or constant-current LED dimming. The 10 MIPS instruction throughput is fast enough for software PI control loops at 1 kHz update rate, while 512 bytes of SRAM hold control variables and lookup tables for non-linear LED gamma correction. The 2.0-5.5V LF cell lets a single-cell Li-ion or 3.3V regulated rail drive both the MCU and the power stage directly, simplifying BOM cost.
Recommended
Consumer Remote Control and Wireless Sensor
For handheld remote controls, key fobs, and wireless sensor end-nodes, the PIC18LF2221T-I/ML provides deterministic low-power control of a sub-GHz transceiver or IR LED over SPI/I2C. Its nanoWatt sleep currents below 1 uA combined with LF 2.0V operation maximize battery life on coin cells or 2x AAA. The Enhanced USART or MSSP bus interfaces directly with common 433/868 MHz transceivers, while 16 GPIOs handle keypad matrix, LED indicators, and wake interrupts. The 4 KB Flash is ample for proprietary RF protocol stacks or IR RC-5/RC-6 encoders, and the in-circuit debugger allows code development without expensive emulator tools.
Recommended
Smart Energy Meter and Sub-Metering
In single-phase smart energy meters and submetering modules, the PIC18LF2221T-I/ML samples current and voltage via its 10-bit ADC, computes energy on-chip, and reports results over UART to a concentrator or display driver. The CCP module times precise sampling windows synchronized to the AC line via Timer1 with capture, while nanoWatt modes keep standby consumption below the 1W budget mandated by EU standby regulations. The 4 KB Flash holds calibration tables and IEC 62053-21 reference algorithms. The LF 2.0-5.5V range lets the meter work from a 3.3V auxiliary rail fed by a transformerless capacitive-drop supply or a small switching supply, simplifying isolation design.
Recommended
Educational and Maker Development Platform
The PIC18LF2221T-I/ML is a popular teaching microcontroller in universities and maker communities because the PIC18 instruction set is well-documented in textbooks, and Microchip's MPLAB X IDE with XC8 compiler is free. Its 28-QFN package is breadboard-adaptable via breakout boards, and the on-chip ICD allows step-through debugging without a separate emulator. With 4 KB Flash, 512 bytes SRAM, and a 10-bit ADC, students learn timer interrupts, ADC conversion, USART communication, and PWM motor control on a single chip. The 2.0-5.5V LF cell tolerates the wide range of USB-derived bench supplies and battery packs used in classrooms, and the low cost encourages hands-on experimentation.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2221T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF2221-I/ML | PIC18F2221-I/ML | PIC18LF2321-I/ML | PIC18F2321-I/ML | PIC18LF2220-I/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-QFN (6x6 mm) | 28-QFN (6x6 mm) - same | 28-QFN (6x6 mm) - same | 28-QFN (6x6 mm) - same | 28-QFN (6x6 mm) - same | 28-QFN (6x6 mm) - same |
| Core | PIC18F 8-bit | PIC18F 8-bit | PIC18F 8-bit | PIC18F 8-bit | PIC18F 8-bit | PIC18F 8-bit |
| Flash Memory | 4 KB | 4 KB | 4 KB | 8 KB (+100%) | 8 KB (+100%) | 4 KB |
| SRAM | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 512 bytes |
| VDD Range | 2.0 V to 5.5 V (LF) | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V |
| ADC | 10-bit, 10 channels | 10-bit, 10 channels | 10-bit, 10 channels | 10-bit, 10 channels | 10-bit, 10 channels | No ADC |
| I/O Pins | 16 | 16 | 16 | 16 | 16 | 16 |
| Max CPU Speed | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) |
| Pricing (qty 100) | $2.61 | $2.65 (est., no T suffix premium) | $2.40 (est.) | $2.95 (est.) | $2.80 (est.) | $2.40 (est., no ADC) |
Key Differentiators
- Low-voltage 2.0-5.5V operation with 4 KB Flash (vs PIC18F2221-I/ML)
- Tape-and-reel 'T' packaging for high-volume SMD assembly (vs PIC18LF2221-I/ML (non-T suffix))
- 10-bit ADC with 10 analog channels integrated (vs PIC18LF2220-I/ML)
- Lower cost than 8 KB Flash variants (vs PIC18LF2321-I/ML)
Design Notes
Solder the 28-QFN exposed thermal pad directly to a continuous ground pour on the top layer. The pad serves both as the package ground reference (improving ADC noise immunity) and as the primary thermal dissipation route. Per Microchip QFN PCB design guidelines, place at least 4 thermal vias in a 1.2 mm pitch array under the pad to the inner ground plane. Decoupling: 100 nF X7R placed within 2 mm of each VDD pin (pins 17 and 28) plus a bulk 4.7 uF X5R on the main supply rail. Estimated: input impedance at pin 17 should be below 1 ohm up to 100 MHz.
Choose a 3.3V LDO with at least 100 mA headroom over the MCU peak consumption. The PIC18LF2221 with all peripherals active at 40 MHz draws approximately 10-15 mA from VDD; in Sleep mode with WDT disabled it drops below 1 uA. Estimated: at 3.3V VDD and 40 MHz, MCU active current is 12 mA; add 30% margin for transients. Brown-out reset (BOR) should be enabled in configuration bits to avoid undefined behavior during supply collapse below 2.0V; use the BOR voltage set to 2.0V for LF cell designs.
Do not confuse the 'LF' low-voltage cell (2.0-5.5V) with the standard PIC18F2221 (4.2-5.5V). Programming a 'LF' firmware image into a standard 'F' part will fail when VDD drops below 4.2V. Configuration bits must enable the internal 8 MHz oscillator block (INTOSC) for low-cost designs without a crystal; do not leave OSC1/OSC2 floating in such cases. RB5/PGM, RB6/PGC, RB7/PGD must not be pulled to VDD during device reset if using low-voltage programming (LVP) mode, or the part will fail to enter run mode.
The 28-QFN package has only 16 GPIO available, so analog and digital signals must share pins. Route analog traces (AN0-AN4) away from switching signals like PWM outputs (CCP1/CCP2) and high-speed USART traces (RC6/RC7). Keep ADC reference pins (RA2/VREF-, RA3/VREF+) short and bypassed with 100 nF + 10 uF capacitors. For I2C lines (RC3/SCL, RC4/SDA), use 4.7 kohm pull-ups to VDD and place the bus capacitance below 400 pF for reliable 400 kHz operation.
Compliance Information
RoHS compliant and lead-free per digchip listing ('LEAD FREE, PLASTIC, QFN-28'). Microchip publishes REACH and conflict-minerals compliance statements on its corporate responsibility page. The 'LF' cell is not AEC-Q100 qualified; use the AEC-Q100-qualified PIC18F counterpart for automotive applications.
