PIC18F4320T-I/ML - 8KB Flash 8-bit MCU, 44-VQFN | Microchip
MPN: PIC18F4320T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.3 | $5.30 |
| 10 | $4.85 | $48.50 |
| 100 | $4.2 | $420.00 |
| 500 | $3.65 | $1,825.00 |
| 1,000 | $3.15 | $3,150.00 |
PIC18F4320T-I/ML Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program and data memory, peripheral interfaces and I/O onto one silicon die. Within the broader semiconductor taxonomy, the PIC18F4320 belongs to the 8-bit microcontroller class, which sits beneath 16-bit and 32-bit MCU families, and ultimately under the embedded processing branch of the power-management-and-control semiconductor hierarchy. The 'PIC' prefix denotes Microchip's Peripheral Interface Controller architecture - a Harvard RISC design with separate program and data buses that allows simultaneous fetch and execute cycles.
Key features include a 10-bit ADC with up to 13 input channels, a 16-bit enhanced capture/compare/PWM module, two USART ports, an SPI/I2C master/slave MSSP peripheral, and the nanoWatt Technology power-managed sleep modes that drop quiescent current into the nanoampere range. The integrated watchdog timer and brown-out reset provide field-grade robustness, while the 10-bit ADC supports touch-sensing and sensor-signal conditioning without an external analog front end.
Architecturally, the PIC18F4320 uses a 16-bit instruction word with 77 single-word instructions, of which most execute in a single instruction cycle. The Flash program memory supports self-programming via ICSP, allowing field firmware updates. The 36 high-current I/O pins can source/sink up to 25 mA each, directly driving LEDs and small relays.
Typical applications include industrial control panels, motor control drivers, sensor-interface boards, low-power battery instrumentation, USB-to-UART bridges, smart sensor nodes, and consumer white goods. The 44-VQFN package suits compact SMD layouts where board space is constrained.
When designing with this part, choose the 44-VQFN footprint when the PCB must stay compact and accept heat-sinking through the exposed pad; allocate the EPAD to a continuous copper pour for thermal dissipation and signal-return integrity. The 8 KB Flash ceiling is the primary constraint for code size.
This page synthesizes distributor pricing, drop-in alternative cross-references, and applied design notes not found in the manufacturer datasheet alone, giving engineers a one-stop reference for PIC18F4320T-I/ML sourcing and design decisions.
Drop-in alternatives for PIC18F4320T-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 PIC18F4320T-I/ML (same form factor and footprint) — differing in Communication, Package, ADC, Core Architecture, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4320-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4320-E/ML
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC18F4420-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4520-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4620-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F46K20-I/ML
✅ Drop-In✓ In Stock
$3.52 / Unit
View Datasheet →PIC18F4320T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory | 8 KB Flash |
| RAM | 512 bytes |
| EEPROM | 256 bytes |
| Instruction Set | 77 single-word instructions |
| Performance | 10 MIPS (100 ns instruction cycle) |
| Maximum Clock Frequency | 40 MHz |
| Operating Voltage | 2.0 V to 5.5 V |
| I/O Pins | 36 |
| ADC | 10-bit, up to 13 channels |
| Timers | 4 (Timer0/1/2/3) |
| Capture/Compare/PWM | 16-bit ECCP + CCP |
| Communication | 2x USART, MSSP (SPI/I2C) |
| Package | 44-VQFN with exposed pad (8x8 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| Power-Saving Modes | nanoWatt Technology |
| Programming Method | ICSP (In-Circuit Serial Programming) |
| RoHS Status | Compliant |
PIC18F4320T-I/ML Pin Configuration
| Pin 1 | NC — Not connected |
| Pin 2 | RA0/AN0 — PORTA bit 0 / ADC analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / ADC analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / ADC analog input 2 / DAC negative reference |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / ADC analog input 3 / DAC positive reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / ADC analog input 4 / SPI slave select |
| Pin 8 | AVSS — Analog ground |
| Pin 9 | AVDD — Analog positive supply |
| Pin 10 | OSC1/RA7 — Crystal oscillator input / PORTA bit 7 |
| Pin 11 | OSC2/RA6 — Crystal oscillator output / PORTA bit 6 |
| Pin 12 | RC0/T1OSO — PORTC bit 0 / Timer1 oscillator output |
| Pin 13 | RC1/T1OSI — PORTC bit 1 / Timer1 oscillator input |
| Pin 14 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM 1 |
| Pin 15 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 16 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 17 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 18 | RC6/TX/CK — PORTC bit 6 / USART async transmit / sync clock |
| Pin 19 | RC7/RX/DT — PORTC bit 7 / USART async receive / sync data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | MCLR/VPP/RE3 — Master clear reset / programming voltage / PORTE bit 3 |
| Pin 23 | RB0/INT0 — PORTB bit 0 / External interrupt 0 |
| Pin 24 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 25 | RB2/INT2 — PORTB bit 2 / External interrupt 2 |
| Pin 26 | RB3/CCP2 — PORTB bit 3 / Capture/Compare/PWM 2 |
| Pin 27 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 28 | RB5/PGM — PORTB bit 5 / ICSP low-voltage programming |
| Pin 29 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 30 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 31 | RD0 — PORTD bit 0 |
| Pin 32 | RD1 — PORTD bit 1 |
| Pin 33 | RD2 — PORTD bit 2 |
| Pin 34 | RD3 — PORTD bit 3 |
| Pin 35 | RD4 — PORTD bit 4 |
| Pin 36 | RD5 — PORTD bit 5 |
| Pin 37 | RD6 — PORTD bit 6 |
| Pin 38 | RD7 — PORTD bit 7 |
| Pin 39 | RE0/RD/AN5 — PORTE bit 0 / parallel-comm read / ADC AN5 |
| Pin 40 | RE1/WR/AN6 — PORTE bit 1 / parallel-comm write / ADC AN6 |
| Pin 41 | RE2/CS/AN7 — PORTE bit 2 / parallel-comm chip select / ADC AN7 |
| Pin 42 | VSS — Ground reference (secondary) |
| Pin 43 | VDD — Positive supply (secondary) |
| Pin 44 | NC — Not connected |
Typical Applications
PIC18F4320T-I/ML is suitable for 6 applications: Industrial Control Panel, Motor Control Driver Board, Sensor Interface Module, Battery-Powered Instrumentation, USB-to-UART Bridge, Consumer Appliance Control.
Industrial Control Panel
The PIC18F4320T-I/ML fits industrial control panels because its 8 KB Flash and 512 B RAM are sufficient for PID control loops, while the 36 I/O pins drive relays, indicator LEDs and keypads. The 10 MIPS throughput handles high-speed sequencing and the 10-bit ADC reads process variables such as temperature and pressure sensors. With -40C to +85C industrial temperature range and nanoWatt sleep modes, the part operates reliably in factory environments and drops into microamp quiescent current during idle periods to meet energy budgets.
Recommended
Motor Control Driver Board
The PIC18F4320T-I/ML suits BLDC and stepper motor driver boards because the 16-bit Enhanced CCP module delivers PWM at up to 40 MHz with fine resolution, while the 4 timers generate complementary PWM channels for three-phase control. The 10 MIPS instruction throughput closes current and velocity loops in real time without software bottlenecks. Operating from 2.0V to 5.5V supports both 3.3V logic interfaces and 5V gate-driver supplies, simplifying bill-of-material across mixed-voltage power stages.
Recommended
Sensor Interface Module
The PIC18F4320T-I/ML is well-matched to sensor-interface modules thanks to its 10-bit ADC with 13 input channels and the MSSP peripheral supporting both SPI and I2C for digital sensor buses. The 36 I/O pins route multiple analog and digital sensor inputs simultaneously, while the nanoWatt Technology reduces sleep current to the nanoampere range for battery-powered sensor nodes. The ICSP self-programming allows OTA-style firmware updates for calibration tables in deployed sensor networks.
Recommended
Battery-Powered Instrumentation
The PIC18F4320T-I/ML supports battery-powered instrumentation through nanoWatt Technology, which drops quiescent current into the nanoampere range during sleep, enabling multi-year coin-cell operation for measurement devices. The 2.0V minimum supply voltage lets the part run directly from two AA alkaline cells, while the 10 MIPS throughput wakes quickly to take measurements and return to sleep. The 8 KB Flash accommodates standard sensor libraries and user calibration data.
Recommended
USB-to-UART Bridge
Although the PIC18F4320 does not include native USB, the part can serve as a UART-to-SPI/I2C or UART-to-GPIO bridge in test fixtures and embedded debug accessories. The 2 USART ports provide simultaneous USB-CDC and external UART channels, while the MSSP peripheral converts between UART and SPI/I2C sensor buses. The 36 I/O and 8 KB Flash support custom protocol stacks for industrial gateways.
Recommended
Consumer Appliance Control
The PIC18F4320T-I/ML integrates well into consumer appliances such as washing machines, microwave ovens and coffee makers, where its 8 KB Flash stores user-interface state machines and the 36 I/O pins drive seven-segment displays, keypads, and triac-fired load switches. The 25 mA source/sink capability on each I/O eliminates driver transistors for indicator LEDs, while the 5V operation is compatible with legacy appliance supply rails. The ICSP interface allows production-line firmware updates.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4320T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4320-I/ML | PIC18F4520-I/ML | PIC18F4420-I/ML |
|---|---|---|---|---|
| Package | 44-VQFN with exposed pad (8x8 mm) | 44-VQFN with exposed pad (8x8 mm) | 44-VQFN with exposed pad (8x8 mm) | 44-VQFN with exposed pad (8x8 mm) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 8 KB | 8 KB | 32 KB | 8 KB |
| RAM | 512 bytes | 512 bytes | 1536 bytes | 512 bytes |
| Operating Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Maximum Clock Frequency | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) |
| I/O Pins | 36 | 36 | 36 | 36 |
| ADC Channels | 13 (10-bit) | 13 (10-bit) | 13 (10-bit) | 8 (10-bit) |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| Unit Price (qty 1) | $5.30 | $5.30 | $7.10 | $5.40 |
Key Differentiators
- Smaller Flash than PIC18F4520 but lowest-cost 44-VQFN variant (vs PIC18F4520-I/ML)
- Industrial -40C to +85C vs extended -40C to +125C of PIC18F4320-E/ML (vs PIC18F4320-E/ML)
- More ADC channels than PIC18F4420-I/ML (vs PIC18F4420-I/ML)
Design Notes
The 44-VQFN exposed thermal pad must be soldered to a continuous copper pour on the PCB to dissipate heat. At full I/O load (36 pins sourcing 25 mA each), internal dissipation can exceed 0.5 W. Estimate: P_dissipation = (VDD - V_IO) x I_OH x N_outputs. With VDD=5V, V_IO=3.4V (LED Vf), I_OH=10 mA and N=16 LEDs, dissipation is ~256 mW. Use at least 100 mm^2 of 1-oz copper plane beneath the EPAD to keep theta_JA below 30 C/W.
Place the 0.1 uF VDD decoupling capacitor within 3 mm of each VDD pin (pins 21 and 43) and a bulk 10 uF tantalum or ceramic cap on the same supply trace. The AVSS/AVDD pair (pins 8 and 9) must be filtered with a separate 10 uH ferrite bead from VDD to keep ADC reference noise below 1 LSB. Route AVSS as a star ground returning to a single point at the voltage regulator.
Do not leave MCLR floating - tie it to VDD through a 10 kohm resistor for normal operation. The ICSP connector (PGD/PGC/MCLR/VSS/VDD) must be accessible for in-field firmware updates. The oscillator pins (OSC1/OSC2) with a crystal need 22 pF load capacitors to GND; using HS_PLL mode for >25 MHz operation requires the PLL configuration bits to be set before increasing the oscillator frequency.
When using the MSSP peripheral in SPI master mode above 5 MHz, keep traces shorter than 50 mm and add 33 ohm series resistors near the source to dampen ringing. For I2C, the SDA/SCL lines (RC4/RC3) require pull-up resistors sized for the total capacitive load: R_pullup <= (VCC - 0.4 V) / (sum of sink currents). Standard mode (100 kHz) typically uses 4.7 kohm; fast mode (400 kHz) typically uses 2.2 kohm.
Configure unused I/O pins as outputs to minimize supply current. The nanoWatt Sleep mode draws typically less than 100 nA with the watchdog timer disabled. Estimate: average current = (I_active x t_active + I_sleep x t_sleep) / T_cycle. If the MCU is active for 1 ms every 100 ms at 10 MIPS (~1 mA active), the average current is approximately (1 mA x 0.001 + 0.0001 mA x 0.099) / 0.1 = ~10.1 uA - suitable for coin-cell applications.
Compliance Information
RoHS and REACH compliance per Microchip product declaration. Not AEC-Q100 qualified - choose PIC18F4320-E/ML or PIC18F4520-E/ML extended-temperature grades for automotive.
