PIC18F2221T-I/ML - 4KB Flash 8-bit MCU, 28-QFN | Microchip
MPN: PIC18F2221T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.1 | $4.10 |
| 10 | $3.68 | $36.80 |
| 100 | $3.27 | $327.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.62 | $2,620.00 |
PIC18F2221T-I/ML Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data bus, integrating CPU core, program memory (Flash), data memory (RAM), peripheral set, and I/O ports. The PIC18F family is the enhanced 8-bit tier within Microchip's PIC architecture, sitting above PIC16F and below the dsPIC/PIC24 16-bit families, and is upward-compatible with PIC16C5X, PIC12CXXX, PIC16CXX, and PIC17CXX devices for portable firmware. Within the broader semiconductor hierarchy, an 8-bit MCU belongs to integrated circuits, then microcontrollers, then embedded controllers, and finally the category of embedded processing.
Key features include 4 KB (2K x 16) Flash program memory, 512 bytes SRAM, 256 bytes EEPROM, ten 10-bit ADC channels with nanoWatt Technology power management, and enhanced Capture/Compare/PWM (ECCP) plus CCP modules. The part operates from 2.0 V to 5.5 V across the industrial temperature window, supports internal 31 kHz to 8 MHz oscillator blocks, and provides up to 22 I/O pins with high-current sink/source capability.
The device is built on a low-power CMOS process with nanoWatt Technology dynamic power switching, idle/sleep modes, and oscillator start-up timer. Hardware peripherals include a master synchronous serial port (MSSP) configurable as SPI or I2C, an enhanced USART with LIN support, and a 10-bit ADC with auto-acquisition and 8 input-mux channels convertible in groups.
Typical applications include consumer white goods, motor-control sensor interfaces, low-power remote sensing nodes, industrial control panels, and battery-charging accessory controllers where Flash re-programmability, low sleep current, and small footprint matter. The QFN-28 package suits hand-held and space-constrained designs. Program development is supported by MPLAB X IDE, MPLAB XC8 compiler, and PICkit or ICD programmer tools for in-circuit debug.
When designing with this part, note that the QFN-28 PCB footprint requires a 6x6 mm land pattern with a central thermal pad for ground and thermal dissipation - omitting the thermal pad will force current limits. Decouple VDD with a 0.1 uF and bulk 1-10 uF capacitor pair close to the pins, and follow Microchip's QFN landing-pattern guideline for via stitching under the e-pad.
This page synthesizes distributor pricing, tape-and-reel drop-in alternatives from the same Microchip PIC18F family, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18F2221T-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 PIC18F2221T-I/ML (same form factor and footprint) — differing in ADC, Core Architecture, Maximum CPU Speed, Package, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2221-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F2321T-I/ML
✅ Drop-In✓ In Stock
$2.96 / Unit
View Datasheet →PIC18F2221T-E/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF2221T-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F1320T-I/ML
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.4 / Unit
View Datasheet →PIC18F2221T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F (Enhanced 8-bit RISC) |
| Program Memory (Flash) | 4 KB (2K x 16) |
| Data Memory (SRAM) | 512 bytes |
| Data EEPROM | 256 bytes |
| Maximum CPU Speed | 40 MHz / 10 MIPS |
| Operating Voltage | 2.0 V to 5.5 V |
| I/O Pins | Up to 22 |
| ADC | 10-bit, up to 10 channels |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | QFN-28 (ML) 6x6 mm with exposed pad |
| Mounting Type | Surface Mount |
| Instruction Set | 77 instructions (single-word) |
| Hardware Multiply | Yes (8x8 single cycle) |
| PWM Channels | Enhanced CCP + CCP modules |
| Communication | MSSP (SPI/I2C), Enhanced USART |
| Power-Saving Modes | nanoWatt Technology (idle/sleep) |
| RoHS Status | Compliant |
PIC18F2221T-I/ML Pin Configuration
| Pin 1 | RA2/AN2/VREF-/CVREF — PORTA bit 2 / Analog input 2 / VREF- / Comparator VREF output |
| Pin 2 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / VREF+ |
| Pin 3 | RA4/AN4/T0CKI/C1OUT — PORTA bit 4 / Analog input 4 / Timer0 clock / Comparator1 output |
| Pin 4 | RA5/AN5/SS/HLVDIN/C2OUT — PORTA bit 5 / Analog input 5 / SPI slave select / HLVD input / Comparator2 output |
| Pin 5 | VDD — Positive supply voltage |
| Pin 6 | VSS — Ground reference |
| Pin 7 | RA7/OSC1/CLKI — PORTA bit 7 / Oscillator crystal input / External clock in |
| Pin 8 | RA6/OSC2/CLKO — PORTA bit 6 / Oscillator crystal output / Clock out |
| Pin 9 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 10 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 I/O |
| Pin 11 | RC2/CCP1 — PORTC bit 2 / Enhanced CCP1 I/O |
| Pin 12 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 13 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 14 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 15 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 16 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 17 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 18 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 19 | RB5/PGM — PORTB bit 5 / ICSP programming low-voltage |
| Pin 20 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 21 | RB3/AN9 — PORTB bit 3 / Analog input 9 |
| Pin 22 | RB2/AN8 — PORTB bit 2 / Analog input 8 |
| Pin 23 | RB1/AN10 — PORTB bit 1 / Analog input 10 |
| Pin 24 | RB0/AN12/INT0/FLT0 — PORTB bit 0 / Analog input 12 / External interrupt 0 / ECCP fault input |
| Pin 25 | MCLR/VPP/RE3 — Master clear reset / Programming voltage / PORTE bit 3 |
| Pin 26 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 27 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 28 | VSS — Ground reference (second ground pin) |
Typical Applications
PIC18F2221T-I/ML is suitable for 6 applications: Industrial Sensor Interface Board, Battery-Powered Remote Sensor Node, Low-Volume Motor Control (Fan/Pump Driver), Consumer White Goods Control Panel, USB HID / CDC Adapter Dongle, Educational / Hobby Development Platform.
Industrial Sensor Interface Board
The PIC18F2221T-I/ML fits industrial 4-20 mA sensor interfaces because its 10-bit ADC with 10 input channels digitizes multiple analog sensor signals while 4 KB Flash hosts the linearization, calibration, and HART-like protocol state machine. Its 2.0-5.5 V operating range accepts 3.3 V and 5 V rails commonly found in industrial field-side loops, and the -40C to +85C industrial window covers most factory environments. The MSSP provides SPI for digital sensor readout (e.g., external temperature ICs) while the enhanced USART handles RS-485 sensor-network wiring. At 10 MIPS, the device can sustain 100 Hz acquisition with on-the-fly FIR filtering before pushing results to a host.
Recommended
Battery-Powered Remote Sensor Node
The PIC18F2221T-I/ML suits battery-powered remote sensing because its nanoWatt Technology power management offers idle/sleep modes that drop quiescent current into the sub-microamp range. The 4 KB Flash holds periodic wake-up measurement routines, time-stamping, and low-power RF packet handlers, while 512 B SRAM buffers the latest sample before transmission. Operating at 2.0-5.5 V supports direct connection to a single-cell Li-ion or two AA cells without a boost converter, simplifying BOM. The QFN-28 6x6 mm package fits sub-1 square inch sensor-node PCBs common in environmental and asset-monitoring deployments.
Recommended
Low-Volume Motor Control (Fan/Pump Driver)
The PIC18F2221T-I/ML drives small brushed DC or BLDC fan and pump controllers thanks to its Enhanced CCP + CCP dual-PWM modules that can generate complementary drive signals for low-side MOSFET bridges. The 10-bit ADC samples back-EMF, current sense, or tachometer feedback for closed-loop speed control, while 4 KB Flash fits PID loop, soft-start, and fault-handler code. Hardware timer resources support a 25 kHz PWM typical switching frequency without CPU overhead. The QFN-28 footprint is small enough to fit inside the motor housing for integrated driver PCBs used in appliance fans.
Recommended
Consumer White Goods Control Panel
The PIC18F2221T-I/ML fits white-goods control panels (washing machines, dishwashers, microwave ovens) because 4 KB Flash holds the user-interface state machine plus sensor processing, and the 10-bit ADC reads keypad/encoder inputs and temperature sensors. The Enhanced USART drives a serial LCD or links to the main appliance MCU, while the MSSP (SPI) drives an LED or segment-display controller. Industrial -40C to +85C tolerates the hot environment inside an appliance chassis near the heater element. Low-cost tape-and-reel QFN-28 supports high-volume SMT assembly lines.
Recommended
USB HID / CDC Adapter Dongle
The PIC18F2221T-I/ML with the Microchip USB stack implements a low-cost USB HID or CDC adapter (keyboard, mouse, COM port). The MSSP can drive a SPI Flash for HID descriptor storage, while 4 KB Flash fits class-compliant USB stacks. The internal 31 kHz to 8 MHz oscillator block generates the 48 MHz USB clock via PLL, eliminating external crystals in many designs. The QFN-28 footprint fits inside compact dongle enclosures. This is a common use case for the PIC18F2xK20 family when more memory is needed, but the PIC18F2221T-I/ML works for minimal HID-only dongles.
Recommended
Educational / Hobby Development Platform
The PIC18F2221T-I/ML is a strong teaching MCU because the PIC18F family is the standard teaching platform in most university embedded-systems curricula, with 4 KB Flash large enough for multi-module student projects yet small enough to teach linker optimization. The QFN-28 surface-mount form factor exercises modern PCB-design skills, while the easy-to-program PICkit-3/4 in-circuit debug workflow reduces classroom setup time. The 77-instruction RISC core provides a clean introduction to assembly and C programming for embedded learners. The wide software ecosystem - MPLAB X, XC8 compiler, and free Microchip libraries - lowers the adoption barrier for hobbyist and student projects.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F2221T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2221-I/ML | PIC18F2321T-I/ML | PIC18F2221T-E/ML | PIC18LF2221T-I/ML | PIC18F1320T-I/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Package | QFN-28 (ML) 6x6 mm | QFN-28 (ML) 6x6 mm - same | QFN-28 (ML) 6x6 mm - same | QFN-28 (ML) 6x6 mm - same | QFN-28 (ML) 6x6 mm - same | QFN-28 (ML) 6x6 mm - same |
| Flash Memory | 4 KB | 4 KB - same | 8 KB (+100%) | 4 KB - same | 4 KB - same | 4 KB - same |
| SRAM | 512 bytes | 512 bytes - same | 512 bytes - same | 512 bytes - same | 512 bytes - same | 512 bytes - same |
| ADC Channels / Resolution | 10 ch / 10-bit | 10 ch / 10-bit - same | 10 ch / 10-bit - same | 10 ch / 10-bit - same | 10 ch / 10-bit - same | 8 ch / 10-bit (-20%) |
| Operating Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V - same | 2.0 V to 5.5 V - same | 2.0 V to 5.5 V - same | 1.8 V to 3.6 V (lower upper rail) | 2.0 V to 5.5 V - same |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C - same | -40C to +85C - same | -40C to +125C (Extended) | -40C to +85C - same | -40C to +85C - same |
| nanoWatt Technology | Yes | Yes - same | Yes - same | Yes - same | Yes - same | No |
| Packaging | Tape & Reel (T) | Tray (no T) | Tape & Reel - same | Tape & Reel - same | Tape & Reel - same | Tape & Reel - same |
Key Differentiators
- Enhanced 8-bit PIC18F core with 4 KB Flash in smallest QFN-28 package (vs PIC18F1320T-I/ML)
- Firmware-upgradable to PIC18F2321T-I/ML on same PCB (vs PIC18F2321T-I/ML)
- Industrial-grade vs Extended-grade temperature variants in same package (vs PIC18F2221T-E/ML)
Design Notes
The QFN-28 (ML) package exposes a thermal/ground pad on the underside. This pad MUST be soldered to the PCB thermal land for electrical ground and heat dissipation. Per Microchip application note AN2042, use a 4.0x4.0 mm thermal pad with a via array (4 to 8 thermal vias) stitching to the ground plane. Omitting the thermal pad increases thermal resistance from 31 C/W to >80 C/W and degrades ADC and oscillator performance.
Decouple VDD (pin 5) with both a 0.1 uF ceramic capacitor (high-frequency bypass) and a 1-10 uF bulk capacitor (low-frequency transient), placed within 5 mm of the IC. Use VSS (pins 6 and 28) as a low-impedance ground return path with a continuous ground plane under the QFN footprint. Add a 10-100 ohm ferrite bead if the supply is shared with an analog ADC rail. Verify on the datasheet that your decoupling matches VDD-VSS pair impedance requirements.
When migrating from PIC18F2221 to PIC18F2321, you get 8 KB Flash but the device ID changes - update your MPLAB project linker script or ICSP device selection. The PIC18F2221T-I/ML industrial temperature range is -40C to +85C; for automotive or extended-industrial (-40C to +125C) you need PIC18F2221T-E/ML. Also note that the T-suffix denotes tape-and-reel - if you order non-T (PIC18F2221-I/ML) you receive tray parts not compatible with SMT pick-and-place reels.
Compliance Information
RoHS compliant per Microchip product page. Lead-free matte-tin QFN plating per ML suffix. Industrial temperature grade - AEC-Q100 not applicable for this part. REACH compliant per Microchip regulatory statement.
