PIC18F4221T-I/PT - 8-bit 40MHz 4KB Flash MCU | Microchip
MPN: PIC18F4221T-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.1 | $3.10 |
| 10 | $2.78 | $27.80 |
| 100 | $2.34 | $234.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.82 | $1,820.00 |
PIC18F4221T-I/PT Overview
What is an 8-bit PIC microcontroller? An 8-bit MCU (microcontroller unit) is a small computer-on-a-chip that processes data 8 bits at a time. PIC microcontrollers from Microchip use a RISC (Reduced Instruction Set Computer) architecture with a Harvard memory structure, separating program and data buses for fast, deterministic execution. Within the broader semiconductor taxonomy, PIC18F belongs to the PIC18 family of enhanced Flash microcontrollers, itself part of the 8-bit MCU category, which sits under embedded controllers and integrated circuits. PIC18F parts are widely used for low-power, cost-sensitive applications requiring simple peripherals and easy migration across pin counts.
Key features of the PIC18F4221T-I/PT include 512 bytes of RAM, 256 bytes of EEPROM data memory, a 10-bit ADC with multiple channels, nanoWatt power-management technology for low-power sleep modes, and 36 digital I/O pins. The device supports supply voltages from 4.2V to 5.5V typical, includes an internal oscillator, multiple timers, USART, MSSP (I2C/SPI), and nanoWatt features for battery-friendly operation.
Architecturally, the PIC18F4221 uses an enhanced RISC core with 77 single-word instructions, hardware multiplier, and 16-bit wide instruction words. The 40 MHz clock delivers up to 10 MIPS (100 ns instruction execution), with interrupt handling, context saving, and a priority interrupt controller for deterministic real-time response. Peripheral integration is mature and well documented across Microchip's toolchain, including MPLAB X IDE, XC8 compilers, and a broad library of application notes.
Typical applications include industrial control, sensor interfaces, low-power remote controls, consumer appliances, automotive body and comfort modules, and USB-less embedded products where cost and power budget matter. The 36 I/O pins and 10-bit ADC also suit HMI (human-machine interface) front panels and instrument clusters.
When designing with this part, plan for a minimum 1uF decoupling capacitor on VDD and place it within 5 mm of the supply pin. For low-power designs, leverage nanoWatt modes (Idle, Sleep, and Timer1 oscillator) and verify the ADC acquisition time against source impedance.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a faster path to a confident part selection.
Drop-in alternatives for PIC18F4221T-I/PT — 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 PIC18F4221T-I/PT (same form factor and footprint) — differing in Package, Timers, Core Architecture, Operating Temperature, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4221-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4221T-I/ML
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18F4220-I/P
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18F4220T-I/ML
✅ Drop-In✓ In Stock
$3.64 / Unit
View Datasheet →PIC18F4220-E/P
✅ Drop-In✓ In Stock
$4.65 / Unit
View Datasheet →PIC18F4221-I/P
✅ Drop-In✓ In Stock
$3.15 / Unit
View Datasheet →PIC18F4221T-I/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit RISC) |
| Program Memory (Flash) | 4 KB (2K x 16) |
| Data RAM | 512 bytes |
| EEPROM | 256 bytes |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Supply Voltage | 4.2 V to 5.5 V |
| I/O Pins | 36 |
| ADC | 10-bit, multi-channel |
| Package | 44-pin TQFP (PT) 10x10 mm |
| Operating Temperature | -40C to +85C (Industrial) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T suffix) |
| Power-Saving Modes | nanoWatt Technology |
| Timers | Multiple 8/16-bit timers |
| Communication | USART, MSSP (I2C/SPI) |
| Instruction Set | 77 single-word instructions |
| RoHS Status | Compliant |
PIC18F4221T-I/PT Pin Configuration
| Pin 1 | RA2/AN2/VREF- — Port A bit 2 / Analog input 2 / Voltage reference negative |
| Pin 2 | RA3/AN3/VREF+ — Port A bit 3 / Analog input 3 / Voltage reference positive |
| Pin 3 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 4 | RA5/AN4/SS — Port A bit 5 / Analog input 4 / SPI slave select |
| Pin 5 | RA6 — Port A bit 6 |
| Pin 6 | RA7 — Port A bit 7 |
| Pin 7 | VSS — Ground reference |
| Pin 8 | OSC1/CLKI/RA7 — External oscillator input / Clock input |
| Pin 9 | OSC2/CLKO/RA6 — External oscillator output / Clock output |
| Pin 10 | VDD — Positive supply voltage |
| Pin 11 | MCLR/VPP/RE3 — Master clear reset / Programming voltage / Port E bit 3 |
| Pin 12 | RB0/INT0 — Port B bit 0 / External interrupt 0 |
| Pin 13 | RB1/INT1 — Port B bit 1 / External interrupt 1 |
| Pin 14 | RB2/INT2 — Port B bit 2 / External interrupt 2 |
| Pin 15 | RB3/CCP2 — Port B bit 3 / Capture/Compare/PWM 2 |
| Pin 16 | RB4 — Port B bit 4 |
| Pin 17 | RB5/PGM — Port B bit 5 / Low-voltage programming |
| Pin 18 | RB6/PGC — Port B bit 6 / ICSP clock |
| Pin 19 | RB7/PGD — Port B bit 7 / ICSP data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | RC0/T1OSO — Port C bit 0 / Timer1 oscillator output |
| Pin 23 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer1 oscillator input / CCP2 |
| Pin 24 | RC2/CCP1 — Port C bit 2 / Capture/Compare/PWM 1 |
| Pin 25 | RC3/SCK/SCL — Port C bit 3 / SPI clock / I2C clock |
| Pin 26 | RC4/SDI/SDA — Port C bit 4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — Port C bit 5 / SPI data out |
| Pin 28 | RC6/TX/CK — Port C bit 6 / USART transmit / clock |
| Pin 29 | RC7/RX/DT — Port C bit 7 / USART receive / data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | RD0 — Port D bit 0 |
| Pin 32 | RD1 — Port D bit 1 |
| Pin 33 | RD2 — Port D bit 2 |
| Pin 34 | RD3 — Port D bit 3 |
| Pin 35 | RD4 — Port D bit 4 |
| Pin 36 | RD5/PSP5 — Port D bit 5 / Parallel slave port bit 5 |
| Pin 37 | RD6/PSP6 — Port D bit 6 / Parallel slave port bit 6 |
| Pin 38 | RD7/PSP7 — Port D bit 7 / Parallel slave port bit 7 |
| Pin 39 | VSS — Ground reference |
| Pin 40 | VDD — Positive supply voltage |
| Pin 41 | RE0/RD/AN5 — Port E bit 0 / Read control / Analog input 5 |
| Pin 42 | RE1/WR/AN6 — Port E bit 1 / Write control / Analog input 6 |
| Pin 43 | RE2/CS/AN7 — Port E bit 2 / Chip select / Analog input 7 |
| Pin 44 | NC — Not connected (per datasheet package variant) |
Typical Applications
PIC18F4221T-I/PT is suitable for 7 applications: Industrial Sensor Interface, Low-Power Remote Control, Consumer Appliance Control, HMI Front Panel, Automotive Body and Comfort Module, Battery-Powered Data Logger, Educational and Prototyping Platform.
Industrial Sensor Interface
The PIC18F4221T-I/PT suits industrial sensor interfaces thanks to its 10-bit ADC, 36 I/O pins, and 4.2-5.5V supply range. Its 40 MHz CPU delivers 10 MIPS, sufficient for sampling multi-channel analog sensors (temperature, pressure, level) at rates up to 100 kS/s aggregate. The 4 KB Flash supports state-machine firmware for sensor linearization and digital filtering. Industrial-grade -40C to +85C operation tolerates factory-floor conditions. nanoWatt power-saving modes enable battery or energy-harvested deployments where the MCU spends most of its time in Sleep, waking only on timer or interrupt. Compared to higher-end Cortex-M0 parts, the PIC18F4221 offers a smaller BOM, mature MPLAB X toolchain, and proven long-term Microchip supply for industrial lifecycle (10+ years).
Recommended
Low-Power Remote Control
Handheld remote controls benefit from the PIC18F4221T-I/PT's nanoWatt technology, which keeps quiescent current below 1 uA in Sleep mode. The internal oscillator eliminates external crystals for cost reduction, while the 36 I/O pins drive key matrices, IR LEDs, and LCD segments directly. 4 KB Flash is sufficient for protocol stacks (RC5, NEC, SIRC) plus application logic. Supply range of 4.2-5.5V accommodates 2-3 AA cells with a boost converter. Compared to ATmega or STM8 alternatives, the PIC18F4221 offers deeper Sleep modes and Microchip's free MPLAB X IDE plus XC8 compiler. Industrial temperature range ensures operation in automotive cabins and outdoor environments.
Recommended
Consumer Appliance Control
Small kitchen and home appliances (coffee machines, blenders, microwave ovens) commonly use the PIC18F4221T-I/PT to drive relays, triacs, keypads, and LED indicators. The 36 I/O pins handle multiple AC zero-cross detection inputs, triac firing outputs, and rotary encoder quadrature inputs. 10 MIPS performance easily runs state-machine firmware for wash cycles, brew profiles, or toast browning algorithms. 4 KB Flash fits typical appliance code, while 256 bytes of EEPROM store user settings and counters. Compared to discrete logic or 8051 designs, the PIC18F4221 reduces BOM cost and PCB area. Industrial temperature grade and Microchip's long-term supply support 7-10 year appliance lifecycles.
Recommended
HMI Front Panel
Human-machine interface front panels for industrial equipment, instruments, and building automation use the PIC18F4221T-I/PT to scan keypads, drive 7-segment or character LCDs, and communicate with main controllers via USART, I2C, or SPI. 36 I/O pins directly drive 4x4 key matrices and 8-digit displays without external logic. 10 MIPS runs debounce, key encoding, and menu navigation smoothly. The 10-bit ADC reads potentiometers and analog sensors for trim controls. Compared to dedicated LCD controllers, integrating the LCD driver in the PIC18F4221 reduces cost and board space. nanoWatt Sleep supports battery-backed clock and last-state memory in power-outage scenarios.
Recommended
Automotive Body and Comfort Module
Automotive body controllers for window lifters, mirror adjusters, seat controllers, and interior lighting use the PIC18F4221T-I/PT. Its industrial -40C to +85C range covers cabin environments, and the 4.2-5.5V supply matches 12V battery rails after regulation. The PIC18F4221E (extended temp) variant handles under-hood conditions. 36 I/O pins drive H-bridge enable lines, current-sense amplifiers, and LIN-bus transceivers. nanoWatt modes support key-off quiescent current budgets below 100 uA per module. Compared to dedicated automotive MCUs, the PIC18F4221 offers lower unit cost for non-safety body applications; safety-critical systems should use AEC-Q100 qualified parts like PIC18F46K22-E/PT.
Recommended
Battery-Powered Data Logger
Portable data loggers for environmental monitoring, cold-chain tracking, and field instrumentation leverage the PIC18F4221T-I/PT's nanoWatt Sleep modes (below 1 uA) to extend battery life to months or years. The 10-bit ADC reads temperature, humidity, and voltage sensors; 4 KB Flash buffers compressed measurement packets before bulk transmission. 256 bytes of EEPROM retain calibration constants and session metadata across power cycles. The internal oscillator eliminates crystals, reducing BOM and quiescent draw. Compared to 32-bit ARM Cortex-M0+ alternatives, the PIC18F4221 offers deeper sleep and simpler toolchain. Microchip's long-term supply and stable silicon revision make this part ideal for 5-10 year deployed logger products.
Recommended
Educational and Prototyping Platform
Universities, hobbyists, and rapid-prototyping labs use the PIC18F4221T-I/PT for embedded systems courses and proof-of-concept designs because of its mature toolchain, abundant application examples, and forgiving peripheral set. Microchip's free MPLAB X IDE plus XC8 compiler removes licensing friction for students and Makers. 36 I/O pins support breadboard-friendly breakout boards; the 10 MIPS performance comfortably runs real-time demos. Compared to launchpad-style ARM boards, the PIC18F4221 is more affordable in single-unit quantities and provides direct register-level programming experience. The TQFP-44 package requires breakout PCB but enables compact final designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4221T-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4221-I/PT | PIC18F4221T-I/ML | PIC18F4220-I/P | PIC18F4220T-I/ML | PIC18F4220-E/P |
|---|---|---|---|---|---|---|
| Package | TQFP-44 (PT) 10x10 mm | TQFP-44 10x10 mm - same | TQFP-44 8x8 mm - smaller | TQFP-44 10x10 mm - same | TQFP-44 8x8 mm - smaller | TQFP-44 10x10 mm - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| 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 | 4 KB | 4 KB | 4 KB |
| RAM | 512 B | 512 B | 512 B | 512 B | 512 B | 512 B |
| Max CPU Speed | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Operating Temperature | -40C to +85C (I) | -40C to +85C (I) | -40C to +85C (I) | -40C to +85C (I) | -40C to +85C (I) | -40C to +125C (E) |
| Packaging | Tape & Reel | Tray | Tape & Reel | Tray | Tape & Reel | Tray |
| I/O Pins | 36 | 36 | 36 | 36 | 36 | 36 |
| Approx. Unit Price (USD) | 3.10 | 3.05 | 3.15 | 2.90 | 2.95 | 3.85 |
Key Differentiators
- Tape & Reel packaging for high-volume assembly (vs PIC18F4221-I/PT)
- Industrial temperature range as standard (vs PIC18F4220-E/P)
- TQFP-44 10x10 mm footprint with full peripheral set (vs PIC18F4221T-I/ML (TQFP-44 8x8 mm))
Design Notes
Place a 100 nF decoupling capacitor as close as possible (within 5 mm) to each VDD pin (pins 10, 21, 40). Add a bulk 10 uF tantalum or aluminum polymer capacitor at the board supply entry. For battery-powered designs, route VDDCORE (if exposed) through a ferrite bead from VDD to reduce digital switching noise coupling into the analog supply. Verify brown-out reset (BOR) configuration matches your supply ramp profile - the default BOR at 4.0V may reset the part on slow 5V rails.
The TQFP-44 10x10 mm package has a 0.8 mm pitch and a 12x12 mm land pattern with thermal pad optional. Route all I/O signals on the top layer to keep via count low; use a continuous ground plane on the bottom layer to provide return paths and reduce EMI. Keep the ICSP pins (RB6/PGC, RB7/PGD) accessible for in-circuit programming without removing the MCU from the board - this allows firmware updates in production. Maintain at least 0.2 mm clearance between traces and package pads to avoid solder bridge defects at assembly.
Do not leave MCLR floating - tie it to VDD through a 10 kohm resistor, with a 100 nF capacitor to ground for noise filtering. Floating MCLR is the most common cause of spurious resets in 8-bit PIC designs. Also configure the CONFIG register for the correct oscillator mode (HS, XT, or internal RC) before code execution - an unconfigured part may fail to start. Finally, when using ADC, ensure the acquisition time exceeds 1.4 us at 40 MHz and that source impedance stays below 2.5 kohm to avoid ADC accuracy degradation.
Estimated: The PIC18F4221T-I/PT dissipates approximately 50 mA * 5V = 250 mW at full CPU load (40 MHz with all peripherals active). The TQFP-44 package has a junction-to-ambient thermal resistance (theta_JA) of approximately 50 C/W on a standard 4-layer JEDEC test board, yielding a temperature rise of 12.5 C above ambient. For most industrial applications this is well within the -40C to +85C operating range; however, in sealed enclosures with no airflow, derate clock speed to 20 MHz or add thermal vias under the exposed pad (if used). Always measure the actual junction temperature in your final enclosure.
Compliance Information
RoHS and REACH compliant per Microchip product page. Standard industrial grade (I suffix, -40C to +85C) - not AEC-Q100 qualified. For AEC-Q100 automotive applications, choose PIC18F46K22-E/PT or PIC18F4620-I/PT (automotive-grade variants).