PIC18LF4321T-I/PT - 8-bit 40MHz 8KB Flash MCU 44-TQFP | Microchip
MPN: PIC18LF4321T-I/PT ✓ פעילPIC18LF4321T-I/PT סקירה
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.
חלופות תחליף ישיר עבור PIC18LF4321T-I/PT — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם PIC18LF4321T-I/PT (אותו גורם צורה וטביעת רגל) — שונים ב Timers, Package, Operating Temperature, ADC, Core Architecture.
PIC18LF4321-I/PT
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
PIC18LF4320T-I/PT
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←PIC18LF4221-I/PT
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←PIC18LF4220T-I/PT
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←PIC18LF4321-I/ML
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←PIC18LF4321T-I/PT דירוגים מרביים ומאפיינים חשמליים
| 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 |
| טמפרטורת פעולה | -40 C to +85 C (Industrial) |
| מארז | 44-pin TQFP (10x10 mm) |
| סוג הרכבה | Surface Mount |
| רמת MSL | 3 (per JEDEC J-STD-020) |
| סטטוס RoHS | Compliant |
| Lead-Free | Yes |
| Flash Endurance | 10K erase/write cycles (typical) |
| EEPROM Endurance | 100K erase/write cycles (typical) |
תצורת פינים של PIC18LF4321T-I/PT
| פין 1 | RC2/CCP1 — Digital I/O RC2 or Capture/Compare/PWM 1 output |
| פין 2 | RC3/SCK/SCL — Digital I/O RC3 or SPI clock / I2C clock |
| פין 3 | RC4/SDI/SDA — Digital I/O RC4 or SPI data in / I2C data |
| פין 4 | RC5/SDO — Digital I/O RC5 or SPI data out |
| פין 5 | RC6/TX/CK — Digital I/O RC6 or EUSART TX / clock |
| פין 6 | RC7/RX/DT — Digital I/O RC7 or EUSART RX / data |
| פין 7 | RD0/PSP0 — Digital I/O RD0 or Parallel Slave Port bit 0 |
| פין 8 | RD1/PSP1 — Digital I/O RD1 or PSP bit 1 |
| פין 9 | RD2/PSP2 — Digital I/O RD2 or PSP bit 2 |
| פין 10 | RD3/PSP3 — Digital I/O RD3 or PSP bit 3 |
| פין 11 | RC0/T1OSO — Digital I/O RC0 or Timer1 oscillator output |
| פין 12 | RC1/T1OSI — Digital I/O RC1 or Timer1 oscillator input |
| פין 13 | Vss — Ground reference for logic and I/O pins |
| פין 14 | Vdd — Positive supply for logic and I/O pins (2.0V-5.5V) |
| פין 15 | RB0/INT0 — Digital I/O RB0 or external interrupt 0 |
| פין 16 | RB1/INT1 — Digital I/O RB1 or external interrupt 1 |
| פין 17 | RB2/INT2 — Digital I/O RB2 or external interrupt 2 |
| פין 18 | RB3/INT3 — Digital I/O RB3 or external interrupt 3 |
| פין 19 | RB4 — Digital I/O RB4 with interrupt-on-change |
| פין 20 | RB5 — Digital I/O RB5 with interrupt-on-change |
| פין 21 | RB6/PGC — Digital I/O RB6 or ICSP clock (programming/debug) |
| פין 22 | RB7/PGD — Digital I/O RB7 or ICSP data (programming/debug) |
| פין 23 | Vss — Ground reference |
| פין 24 | Vdd — Positive supply (2.0V-5.5V) |
| פין 25 | RD4/PSP4 — Digital I/O RD4 or PSP bit 4 |
| פין 26 | RD5/PSP5 — Digital I/O RD5 or PSP bit 5 |
| פין 27 | RD6/PSP6 — Digital I/O RD6 or PSP bit 6 |
| פין 28 | RD7/PSP7 — Digital I/O RD7 or PSP bit 7 |
| פין 29 | RE0/RD — Digital I/O RE0 or parallel port read |
| פין 30 | RE1/WR — Digital I/O RE1 or parallel port write |
| פין 31 | RE2/CS — Digital I/O RE2 or parallel port chip select |
| פין 32 | AVdd — Analog positive supply; tie to Vdd if ADC unused |
| פין 33 | AVss — Analog ground; tie to Vss |
| פין 34 | RA0/AN0 — Digital I/O RA0 or analog input 0 |
| פין 35 | RA1/AN1 — Digital I/O RA1 or analog input 1 |
| פין 36 | RA2/AN2/Vref- — Digital I/O RA2 or analog input 2 or ADC Vref- |
| פין 37 | RA3/AN3/Vref+ — Digital I/O RA3 or analog input 3 or ADC Vref+ |
| פין 38 | RA4/T0CKI — Digital I/O RA4 or Timer0 clock input (open-drain) |
| פין 39 | RA5/AN4 — Digital I/O RA5 or analog input 4 |
| פין 40 | OSC1/CLKI — Crystal/clock input or external clock in |
| פין 41 | OSC2/CLKO — Crystal output or clock output |
| פין 42 | D-/VM — USB D- or USB voltage monitor input |
| פין 43 | D+/VP — USB D+ or ADC programming voltage input |
| פין 44 | MCLR/Vpp — Master Clear (reset, active low) / programming voltage |
יישומים טיפוסיים
PIC18LF4321T-I/PT מתאים עבור 6 יישוםs: 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.
מומלץ
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.
מומלץ
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.
מומלץ
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.
מומלץ
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.
מומלץ
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.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור PIC18LF4321T-I/PT — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | 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 |
מבדילים עיקריים
- Integrated USB 2.0 full-speed SIE with internal transceiver on a 44-TQFP LF package (לעומתPIC18LF4320T-I/PT)
- Low-voltage LF operation from 2.0V to 5.5V (לעומתPIC18F4321T-I/PT)
- Drop-in replacement on the same 44-TQFP land pattern with identical firmware image (לעומתPIC18LF4221-I/PT)
הערות תכנון
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.
מידע על תאימות
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.