PIC18LF4321T-I/PT - 8-bit 40MHz 8KB Flash MCU 44-TQFP | Microchip
MPN: PIC18LF4321T-I/PT ✓ نشطPIC18LF4321T-I/PT نظرة عامة
A PIC18 microcontroller is a modified Harvard RISC architecture 8-bit MCU built around an enhanced instruction set with 16-bit instructions and an 8-bit data path. PIC18 devices sit within the broader PIC family hierarchy: PIC10/12/16/18 -> 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. The PIC18 line specifically targets high-performance applications with up to 40 MHz operation, integrated peripherals such as ADC, PWM, I2C, SPI, UART, and USB (where applicable), and self-programming Flash memory. Compared to baseline PIC16 parts, PIC18 adds linear program memory addressing, a hardware multiplier, and a richer interrupt controller.
Key features of the PIC18LF4321 include 8 KB of self-programmable Flash, 256 bytes of EEPROM, 34 digital I/O pins, a 10-bit ADC with multiple channels, two analog comparators, two 8-bit timers plus three 16-bit timers, an enhanced USART, MSSP (I2C/SPI), and the standard PIC18 nanoWatt power-managed feature set. The Flash endurance is rated for a minimum of 10K erase/write cycles and data EEPROM for 100K cycles, supporting frequent in-field firmware updates.
The LF family uses Microchip's nanoWatt technology with multiple power-managed operating modes including run, idle, sleep, deep sleep, and RTCC from a low-power oscillator. This architecture reduces quiescent current to microampere levels in sleep, enabling battery-powered designs that wake on interrupts and resume execution within microseconds.
Typical applications include industrial sensor interfaces, home appliances and white goods, low-cost motor control, USB peripherals on the PIC18F/LF4321 family, battery-powered metering, and consumer electronics. The 44-pin TQFP footprint and Microchip's free MPLAB X IDE with XC8 compiler create a low-cost entry point for embedded engineers.
When designing with this part, verify the core supply voltage and analog reference setup; the LF variant does not include a 5V-only regulator and requires proper decoupling on AVDD/AVSS pins. Engineers upgrading from the PIC18F4321 (F = standard voltage, 4.2V-5.5V) must verify that their firmware operates correctly across the LF's wider 2.0V-5.5V range.
This page synthesizes distributor pricing, drop-in same-package alternatives (PIC18LF4321, PIC18LF4320T-I/PT), and practical design notes not consolidated in the manufacturer datasheet.
بدائل مباشرة لـ PIC18LF4321T-I/PT — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع PIC18LF4321T-I/PT (نفس عامل الشكل والبصمة) — يختلف في Timers, Package, Operating Temperature, ADC, Core Architecture.
PIC18LF4321-I/PT
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
PIC18LF4320T-I/PT
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←PIC18LF4221-I/PT
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←PIC18LF4220T-I/PT
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←PIC18LF4321-I/ML
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منهاتواصل لمعرفة السعر
عرض ورقة البيانات ←PIC18LF4321T-I/PT الحدود القصوى والخصائص الكهربائية
| Core Architecture | PIC18 (8-bit RISC, enhanced Harvard) |
| Program Memory | 8 KB (4K x 16) Flash |
| Data SRAM | 512 bytes |
| Data EEPROM | 256 bytes |
| CPU Clock Speed | 40 MHz (max) |
| Supply Voltage (LF) | 2.0 V to 5.5 V |
| I/O Pins | 34 |
| Timers | 2 8-bit + 3 16-bit |
| درجة حرارة التشغيل | -40 C to +85 C (Industrial) |
| العلبة | 44-pin TQFP (10x10 mm) |
| نوع التركيب | Surface Mount |
| مستوى MSL | 3 (per JEDEC J-STD-020) |
| حالة RoHS | Compliant |
| Lead-Free | Yes |
| Flash Endurance | 10K erase/write cycles (typical) |
| EEPROM Endurance | 100K erase/write cycles (typical) |
تكوين أطراف PIC18LF4321T-I/PT
| دبوس 1 | RC2/CCP1 — Digital I/O RC2 or Capture/Compare/PWM 1 output |
| دبوس 2 | RC3/SCK/SCL — Digital I/O RC3 or SPI clock / I2C clock |
| دبوس 3 | RC4/SDI/SDA — Digital I/O RC4 or SPI data in / I2C data |
| دبوس 4 | RC5/SDO — Digital I/O RC5 or SPI data out |
| دبوس 5 | RC6/TX/CK — Digital I/O RC6 or EUSART TX / clock |
| دبوس 6 | RC7/RX/DT — Digital I/O RC7 or EUSART RX / data |
| دبوس 7 | RD0/PSP0 — Digital I/O RD0 or Parallel Slave Port bit 0 |
| دبوس 8 | RD1/PSP1 — Digital I/O RD1 or PSP bit 1 |
| دبوس 9 | RD2/PSP2 — Digital I/O RD2 or PSP bit 2 |
| دبوس 10 | RD3/PSP3 — Digital I/O RD3 or PSP bit 3 |
| دبوس 11 | RC0/T1OSO — Digital I/O RC0 or Timer1 oscillator output |
| دبوس 12 | RC1/T1OSI — Digital I/O RC1 or Timer1 oscillator input |
| دبوس 13 | Vss — Ground reference for logic and I/O pins |
| دبوس 14 | Vdd — Positive supply for logic and I/O pins (2.0V-5.5V) |
| دبوس 15 | RB0/INT0 — Digital I/O RB0 or external interrupt 0 |
| دبوس 16 | RB1/INT1 — Digital I/O RB1 or external interrupt 1 |
| دبوس 17 | RB2/INT2 — Digital I/O RB2 or external interrupt 2 |
| دبوس 18 | RB3/INT3 — Digital I/O RB3 or external interrupt 3 |
| دبوس 19 | RB4 — Digital I/O RB4 with interrupt-on-change |
| دبوس 20 | RB5 — Digital I/O RB5 with interrupt-on-change |
| دبوس 21 | RB6/PGC — Digital I/O RB6 or ICSP clock (programming/debug) |
| دبوس 22 | RB7/PGD — Digital I/O RB7 or ICSP data (programming/debug) |
| دبوس 23 | Vss — Ground reference |
| دبوس 24 | Vdd — Positive supply (2.0V-5.5V) |
| دبوس 25 | RD4/PSP4 — Digital I/O RD4 or PSP bit 4 |
| دبوس 26 | RD5/PSP5 — Digital I/O RD5 or PSP bit 5 |
| دبوس 27 | RD6/PSP6 — Digital I/O RD6 or PSP bit 6 |
| دبوس 28 | RD7/PSP7 — Digital I/O RD7 or PSP bit 7 |
| دبوس 29 | RE0/RD — Digital I/O RE0 or parallel port read |
| دبوس 30 | RE1/WR — Digital I/O RE1 or parallel port write |
| دبوس 31 | RE2/CS — Digital I/O RE2 or parallel port chip select |
| دبوس 32 | AVdd — Analog positive supply; tie to Vdd if ADC unused |
| دبوس 33 | AVss — Analog ground; tie to Vss |
| دبوس 34 | RA0/AN0 — Digital I/O RA0 or analog input 0 |
| دبوس 35 | RA1/AN1 — Digital I/O RA1 or analog input 1 |
| دبوس 36 | RA2/AN2/Vref- — Digital I/O RA2 or analog input 2 or ADC Vref- |
| دبوس 37 | RA3/AN3/Vref+ — Digital I/O RA3 or analog input 3 or ADC Vref+ |
| دبوس 38 | RA4/T0CKI — Digital I/O RA4 or Timer0 clock input (open-drain) |
| دبوس 39 | RA5/AN4 — Digital I/O RA5 or analog input 4 |
| دبوس 40 | OSC1/CLKI — Crystal/clock input or external clock in |
| دبوس 41 | OSC2/CLKO — Crystal output or clock output |
| دبوس 42 | D-/VM — USB D- or USB voltage monitor input |
| دبوس 43 | D+/VP — USB D+ or ADC programming voltage input |
| دبوس 44 | MCLR/Vpp — Master Clear (reset, active low) / programming voltage |
التطبيقات النموذجية
PIC18LF4321T-I/PT مناسب لـ 6 التطبيقs: USB HID Peripheral Devices, Industrial Sensor Conditioning and Logging, Battery-Powered Metering Devices, Home Appliance Control Boards, USB-to-UART Bridge Dongles, Consumer Electronics and Educational Kits.
USB HID Peripheral Devices
The PIC18LF4321T-I/PT is purpose-built for low-cost USB peripherals because it integrates a USB 2.0 full-speed SIE, 1.5 kB endpoint RAM, and an internal pull-up resistor on the D+ line. With 8 KB Flash and 512 B SRAM it can host HID class firmware (keyboards, mice, game controllers) or CDC class firmware (virtual COM ports) while running at 3.3V directly from the USB 5V rail through a 3.3V LDO. The 40 MHz CPU delivers 10 MIPS, sufficient for polling-rate firmware that processes USB transactions and HID reports in real time. The 44-TQFP footprint exposes the dedicated D+/D- pins and is industry standard for PIC18 USB development boards, allowing direct reuse of Microchip's PICDEM USB reference designs.
موصى به
Industrial Sensor Conditioning and Logging
The PIC18LF4321T-I/PT fits industrial 4-20 mA or 0-10V sensor conditioning boards thanks to its 10-bit ADC (multiple channels), 256 B EEPROM for calibration constants, and -40C to +85C industrial temperature rating. With 34 I/O it can interface 4-20 mA loops via op-amps, drive LED bar indicators, and read a keypad or rotary encoder simultaneously. The 256 B EEPROM is rated for 100K erase/write cycles, ideal for logging hour meters or tamper counters in deployed sensor nodes. The 2.0V-5.5V supply range supports both 3.3V logic from modern sensors and 5V from legacy industrial boards without level shifters, reducing BOM and PCB complexity.
موصى به
Battery-Powered Metering Devices
The PIC18LF4321T-I/PT's nanoWatt technology and 2.0V minimum supply make it ideal for battery-powered metering products such as gas, water, or electric meters running from a 3.6V Li-SOCl2 primary cell. The deep-sleep current drops to sub-microamp levels when the MCU is idle, waking on RTCC alarm or interrupt to record metering events. The 512 B SRAM is sufficient for averaging and rolling-window calculations, while the 256 B EEPROM persists accumulated consumption across power cycles. Running at 4 MHz from the internal oscillator in sleep, the average current draw is well within the budget of a 2.4 Ah primary cell, supporting 10+ year service life on a single battery.
موصى به
Home Appliance Control Boards
The PIC18LF4321T-I/PT is widely used in white-goods control boards (washing machines, dishwashers, refrigerators) where its 40 MHz core, 34 I/O, and PWM/CCP peripherals drive triac-controlled AC loads, brush DC motors, and solenoid valves. The 8 KB Flash accommodates motor sequencing and fault-detection state machines, while the EUSART links to a UI board or Bluetooth module for app connectivity. The -40C to +85C industrial range covers appliance cabinet environments and garage installations. The 44-TQFP package is robust to wave-solder profiles used in white-goods manufacturing, with MSL-3 moisture handling standard for production lines.
موصى به
USB-to-UART Bridge Dongles
The PIC18LF4321T-I/PT can implement a CDC-class USB-to-UART bridge (virtual COM port) using its integrated USB SIE and EUSART, eliminating an external USB-to-serial chip on field-service dongles, IoT gateways, or industrial debug adapters. The 8 KB Flash hosts the CDC ACM stack and a configuration channel, while the 512 B SRAM buffers CDC packets at 12 Mbps full-speed USB rates. Power is drawn directly from USB VBUS through a 3.3V LDO such as the MIC5205. This topology replaces the legacy FTDI FT232R with a Microchip-native single-chip solution, reducing BOM cost and PCB area while remaining drop-in compatible with PC-side CDC drivers across Windows, macOS, and Linux.
موصى به
Consumer Electronics and Educational Kits
The PIC18LF4321T-I/PT remains a popular choice for consumer electronics and educational kits because of its free MPLAB X toolchain support, free XC8 compiler, and abundant Microchip application notes and code examples. The 8 KB Flash and 512 B SRAM support C-compiled curricula covering timers, ADC, PWM, I2C, SPI, and USB, while the 44-TQFP package exposes enough I/O for breadboard-friendly breakout boards. Hobbyists and university labs reuse the same MCU across robotics, motor control, IoT, and audio projects because the PIC18 instruction set, registers, and peripheral library are stable across generations, making migration from PIC18F to PIC18LF or to PIC24/dsPIC painless.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ PIC18LF4321T-I/PT — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | PIC18LF4321-I/PT | PIC18LF4320T-I/PT | PIC18LF4221-I/PT | PIC18LF4220T-I/PT | PIC18LF4321-I/ML |
|---|---|---|---|---|---|---|
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-QFN - different land pattern |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 8 KB | 8 KB | 8 KB | 4 KB (-50%) | 4 KB (-50%) | 8 KB |
| Data SRAM | 512 B | 512 B | 512 B | 256 B (-50%) | 256 B (-50%) | 512 B |
| CPU Clock Speed | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage | 2.0V to 5.5V (LF) | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V |
| I/O Pins | 34 | 34 | 34 | 34 | 34 | 34 |
| USB 2.0 SIE | Yes (integrated, internal transceiver) | Yes | No (4320 lacks SIE) | Yes (4221 includes SIE) | No (4220 lacks SIE) | Yes |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
أبرز الفروقات
- Integrated USB 2.0 full-speed SIE with internal transceiver on a 44-TQFP LF package (مقابلPIC18LF4320T-I/PT)
- Low-voltage LF operation from 2.0V to 5.5V (مقابلPIC18F4321T-I/PT)
- Drop-in replacement on the same 44-TQFP land pattern with identical firmware image (مقابلPIC18LF4221-I/PT)
ملاحظات التصميم
Place 100 nF decoupling capacitors as close as possible to each VDD/VSS pair (44-TQFP has two VDD pins: 14 and 24; and two VSS pins: 13 and 23). Add a 10 uF bulk capacitor near the package to support USB inrush current. The AVdd/AVss pair (pins 32/33) must each have a 100 nF decoupling capacitor tied to quiet analog ground, and AVdd should be tied to Vdd even if the ADC is unused. For USB applications, place a 0.01 uF on Vbus and a ferrite bead between Vbus and the 3.3V LDO per Microchip's USB hardware design guidelines.
The 44-pin TQFP (10x10 mm, 0.8 mm pitch) requires a 4-layer PCB with a continuous ground plane beneath the package for thermal dissipation and EMC. Route the USB D+/D- pair as a 90-ohm differential, length-matched within 1 mm, with no stubs. The crystal traces (OSC1/OSC2) must be short and surrounded by ground, and the MCLR pin requires a 10 kohm pull-up to VDD plus a 100 nF to ground for noise filtering; omitting the MCLR capacitor allows spurious resets during USB plug events.
Do not confuse the LF suffix (2.0V-5.5V) with the F suffix (4.2V-5.5V) when migrating firmware between PIC18F4321 and PIC18LF4321 - the LF variant runs the ADC and PLL differently at low VDD, and code compiled assuming 5V may have ADC reference scaling errors at 3.3V. Also note that the 'T' in 'PIC18LF4321T-I/PT' refers to tape-and-reel, not a temperature grade; the 'I' in 'I/PT' is the -40C to +85C industrial range.
Estimated: at 40 MHz CPU clock with USB active, switching noise on VDD can reach 50 mVpp; an LC pi-filter (10 uH + 10 uF + 100 nF) on the VDD trace near the MCU reduces this to under 10 mVpp. For mixed-signal designs, separate the analog and digital VDD/AVDD traces to a single-point join near the MCU, and keep ADC traces short and away from the 40 MHz oscillator traces to minimize ADC crosstalk.
معلومات الامتثال
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - choose PIC18F4321-I/PT or PIC18F4321-E/PT for automotive applications. Halogen-free status not stated by Microchip for this part.