PIC18F4331-I/PT - 8-bit 40MHz MCU 8KB Flash 44-TQFP | Microchip
MPN: PIC18F4331-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.77 | $4.77 |
| 10 | $4.3 | $43.00 |
| 100 | $3.85 | $385.00 |
| 500 | $3.45 | $1,725.00 |
| 1,000 | $3.05 | $3,050.00 |
PIC18F4331-I/PT Overview
A microcontroller (MCU) is a single-chip computer that combines a CPU core, program memory, data RAM, and peripherals on one integrated circuit. The PIC18F family represents Microchip's enhanced 8-bit architecture, positioned between the baseline PIC10/12/16 families and the 16-bit PIC24/dsPIC families. Within this hierarchy, the PIC18F4331 belongs to the PIC18F4331/4431 sub-family, which targets motor control and power conversion applications. These MCUs fall under the broader category of embedded microcontrollers -> microcontrollers -> integrated circuits -> semiconductors.
Key differentiating features include nanoWatt Technology for power-managed sleep modes, a 14-bit resolution Power Control PWM (PCPWM) module with up to 8 channels, a 10-bit A/D converter with up to 9 channels, and a hardware multiplier for 8x8 single-cycle operations. The 44-pin TQFP package provides 36 digital I/O pins plus dedicated analog, PWM, and communication peripheral pins. The integrated Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) and Master I2C/SPI interfaces enable communication with external sensors, motor drivers, and displays.
Architecturally, the PIC18F4331 uses a 16-bit instruction word modified Harvard architecture with separate program and data buses. The 40 MHz oscillator drives a four-phase instruction pipeline that delivers up to 10 MIPS throughput, sufficient for closed-loop motor control algorithms. The dedicated Power Control PWM block supports complementary PWM outputs with programmable dead-band delay, hardware fault inputs, and a 14-bit resolution suitable for variable-frequency drive and UPS applications. This combination of peripherals eliminates the need for external PWM controllers and reduces overall BOM cost in motor drive designs.
Typical applications include brushless DC (BLDC) motor drives, three-phase induction motor control, switched-mode power supplies with power-factor correction, uninterruptible power supplies (UPS), and industrial variable-frequency drives. The 8 KB flash is sufficient for small motor-control state machines, sensored or sensorless commutation algorithms, and basic power-supply control loops.
When designing with this MCU, ensure the decoupling network follows Microchip's reference design with at least one 100 nF ceramic capacitor per power pin and a 10 uF bulk capacitor on VDD. The PCPWM module requires careful configuration of the PWM period, dead-band delay, and fault input polarity to prevent shoot-through in the half-bridge. The In-Circuit Debugger (ICD) or MPLAB PICkit programmer should be reserved with the standard RJ-11 ICSP header.
This page synthesizes distributor pricing, same-brand drop-in alternatives from Microchip's PIC18F family, and practical design notes that go beyond the manufacturer datasheet. Engineers can use the comparison_table below to evaluate PIC18F4331-I/PT against same-package PIC18F4431-I/PT (more flash), PIC18F4321-I/PT, and PIC18F4320-I/PT substitutes for legacy designs.
Drop-in alternatives for PIC18F4331-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 PIC18F4331-I/PT (same form factor and footprint) — differing in Operating Temperature, Package, ADC, Timers, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4431-I/PT
✅ Drop-In✓ In Stock
$4.79 / Unit
View Datasheet →PIC18F4331-I/ML
✅ Drop-In✓ In Stock
$5.32 / Unit
View Datasheet →PIC18F4321-I/ML
✅ Drop-In✓ In Stock
$1.22 / Unit
View Datasheet →PIC18F4320-I/PT
✅ Drop-In✓ In Stock
$3.62 / Unit
View Datasheet →PIC18F4220-I/P
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18F4331-I/PT Maximum Ratings & Electrical Characteristics
| Core | PIC18F 8-bit |
| Program Memory | 8 KB (4K x 16) Flash |
| RAM | 768 bytes |
| EEPROM | 256 bytes |
| Maximum CPU Frequency | 40 MHz (10 MIPS) |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| I/O Pins | 36 |
| A/D Converter | 10-bit, up to 9 channels |
| PWM Module | Power Control PWM, 14-bit, up to 8 channels |
| Operating Temperature (I suffix) | -40 C to +85 C (industrial) |
| Package | 44-pin TQFP (PT) 10x10 mm |
| Mounting Type | Surface Mount |
| MSL Level | 3 (168 hours) |
| RoHS Status | Compliant |
| Communication Interfaces | EUSART, I2C, SPI |
PIC18F4331-I/PT Pin Configuration
| Pin 1 | RC0 — Digital I/O PORTC bit 0 / PWM output |
| Pin 2 | RC1 — Digital I/O PORTC bit 1 / PWM output |
| Pin 3 | RC2 — Digital I/O PORTC bit 2 / PWM output |
| Pin 4 | RC3 — Digital I/O PORTC bit 3 / PWM output |
| Pin 5 | RC4 — Digital I/O PORTC bit 4 |
| Pin 6 | RC5 — Digital I/O PORTC bit 5 |
| Pin 7 | RC6 — Digital I/O PORTC bit 6 / TX |
| Pin 8 | RC7 — Digital I/O PORTC bit 7 / RX |
| Pin 9 | VSS — Ground reference |
| Pin 10 | VDD — Positive supply voltage (4.2 V to 5.5 V) |
| Pin 11 | OSC1 — Oscillator input / external clock in |
| Pin 12 | OSC2 — Oscillator output / clock out |
| Pin 13 | RA0 — Digital I/O PORTA bit 0 / AN0 analog input |
| Pin 14 | RA1 — Digital I/O PORTA bit 1 / AN1 analog input |
| Pin 15 | RA2 — Digital I/O PORTA bit 2 / AN2 / VREF- |
| Pin 16 | RA3 — Digital I/O PORTA bit 3 / AN3 / VREF+ |
| Pin 17 | RA4 — Digital I/O PORTA bit 4 |
| Pin 18 | RA5 — Digital I/O PORTA bit 5 / AN4 |
| Pin 19 | VSS — Ground reference (second) |
| Pin 20 | VDD — Positive supply voltage (second) |
| Pin 21 | RB0 — Digital I/O PORTB bit 0 / INT0 |
| Pin 22 | RB1 — Digital I/O PORTB bit 1 / INT1 |
| Pin 23 | RB2 — Digital I/O PORTB bit 2 |
| Pin 24 | RB3 — Digital I/O PORTB bit 3 |
| Pin 25 | RB4 — Digital I/O PORTB bit 4 |
| Pin 26 | RB5 — Digital I/O PORTB bit 5 / PGM |
| Pin 27 | RB6 — Digital I/O PORTB bit 6 / PGC |
| Pin 28 | RB7 — Digital I/O PORTB bit 7 / PGD |
| Pin 29 | RD0 — Digital I/O PORTD bit 0 |
| Pin 30 | RD1 — Digital I/O PORTD bit 1 |
| Pin 31 | RD2 — Digital I/O PORTD bit 2 |
| Pin 32 | RD3 — Digital I/O PORTD bit 3 |
| Pin 33 | RD4 — Digital I/O PORTD bit 4 |
| Pin 34 | RD5 — Digital I/O PORTD bit 5 |
| Pin 35 | RD6 — Digital I/O PORTD bit 6 |
| Pin 36 | RD7 — Digital I/O PORTD bit 7 |
| Pin 37 | RE0 — Digital I/O PORTE bit 0 / AN5 |
| Pin 38 | RE1 — Digital I/O PORTE bit 1 / AN6 |
| Pin 39 | RE2 — Digital I/O PORTE bit 2 / AN7 |
| Pin 40 | RE3 — Digital I/O PORTE bit 3 / AN8 |
| Pin 41 | AVDD — Analog positive supply |
| Pin 42 | AVSS — Analog ground reference |
| Pin 43 | MCLR — Master clear (reset) input |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC18F4331-I/PT is suitable for 6 applications: Brushless DC (BLDC) Motor Drive, Three-Phase Induction Motor VFD, Switched-Mode Power Supply with PFC, Uninterruptible Power Supply (UPS) Control, Industrial Servo Drive, HID Lighting Ballast.
Brushless DC (BLDC) Motor Drive
The PIC18F4331-I/PT is widely used in sensored and sensorless brushless DC (BLDC) motor drives up to several hundred watts. The dedicated 14-bit Power Control PWM module generates three-phase complementary PWM outputs with programmable dead-band delay, eliminating the need for an external motor-control coprocessor. With 40 MHz CPU speed delivering 10 MIPS, the device runs commutation tables and PI speed/current loops at PWM frequencies up to 20 kHz. The integrated 10-bit A/D samples motor current and back-EMF, while 8 KB flash holds the commutation state machine. Hardware fault inputs to the PCPWM block shut down PWM outputs within one cycle, protecting the half-bridge from shoot-through.
Recommended
Three-Phase Induction Motor VFD
Variable-frequency drives (VFDs) for three-phase induction motors use the PIC18F4331-I/PT for scalar (V/Hz) and basic vector control. The 14-bit PCPWM produces a three-phase sine-modulated PWM with up to 8 channels, supporting both open-loop V/Hz and closed-loop slip compensation. The 40 MHz MIPS budget is sufficient for software-based Park/Clarke transforms at modest PWM rates, while the 10-bit A/D reads DC bus voltage and phase currents. The 256-byte EEPROM stores motor nameplate parameters and V/Hz profile, preserving settings across power cycles.
Recommended
Switched-Mode Power Supply with PFC
Active Power Factor Correction (PFC) boost pre-regulators for switch-mode power supplies use the PIC18F4331-I/PT for closed-loop current shaping at the AC mains. The 14-bit PCPWM produces the boost switch drive signal with frequency modulation, while the 10-bit A/D samples input voltage, input current, and output DC bus. The 40 MHz CPU runs average-current-mode control loops with update rates up to 100 kHz. The 8 KB flash holds firmware for soft-start, brownout protection, and AC line cycle handling. The 5 V supply rail matches typical PFC controller IC power requirements.
Recommended
Uninterruptible Power Supply (UPS) Control
Single-phase and three-phase UPS systems use the PIC18F4331-I/PT for inverter control, battery management, and AC line synchronization. The dedicated PCPWM generates the 50/60 Hz sine-modulated inverter output, while the 10-bit A/D reads battery voltage, output current, and grid voltage for transfer-switch decisions. With 8 KB flash, the device fits state machines for offline/online/charge modes plus RS-232 monitoring firmware. nanoWatt Technology allows the MCU to monitor the line continuously at low current draw, extending battery life in standby mode.
Recommended
Industrial Servo Drive
Industrial servo drives for stepper and small DC servo motors leverage the PIC18F4331-I/PT's PCPWM for precise current and velocity control. The 14-bit PWM resolution enables smooth torque output at low speeds, while the dedicated fault inputs provide hardware-level overcurrent protection within one PWM cycle. The EUSART and SPI peripherals communicate with HMI displays and encoder feedback ASICs. The 8 KB flash holds profile generation tables for trapezoidal and S-curve motion profiles, while 768 bytes RAM is sufficient for real-time position loop variables.
Recommended
HID Lighting Ballast
High-Intensity Discharge (HID) lamp ballasts for street and stadium lighting use the PIC18F4331-I/PT for full-bridge resonant inverter control. The dedicated PCPWM generates complementary high-frequency drive signals for the half-bridge MOSFETs, with programmable dead-band delay preventing shoot-through. The 40 MHz CPU runs the warm-up, ignition, and steady-state phases with adaptive frequency control to maintain lamp power across the operating range. The 10-bit A/D monitors lamp current, voltage, and temperature, while the 8 KB flash fits the ignition state machine and protection logic.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4331-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4431-I/PT | PIC18F4331-I/ML | PIC18F4321-I/ML | PIC18F4320-I/PT | PIC18F4220-I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin TQFP (PT) 10x10 mm | 44-pin TQFP (PT) - same | 44-pin QFN (ML) - same die | 44-pin QFN (ML) - same | 44-pin TQFP (PT) - same | 40-pin PDIP (P) - lower pin count |
| Program Memory | 8 KB Flash | 16 KB Flash (+100%) | 8 KB Flash | 8 KB Flash | 8 KB Flash | 4 KB Flash (-50%) |
| RAM | 768 bytes | 768 bytes | 768 bytes | 768 bytes | 768 bytes | 256 bytes (-66%) |
| Maximum Clock Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| PWM Module | Power Control PWM, 14-bit, 8 channels | Power Control PWM, 14-bit, 8 channels | Power Control PWM, 14-bit, 8 channels | CCP/ECCP PWM (different module) | CCP PWM (no PCPWM) | CCP PWM (no PCPWM) |
| A/D Converter | 10-bit, 9 channels | 10-bit, 9 channels | 10-bit, 9 channels | 10-bit, 13 channels | 10-bit, 13 channels | 10-bit, 8 channels |
| I/O Pins | 36 | 36 | 36 | 36 | 36 | 32 |
| Operating Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V (wider range) |
Key Differentiators
- Dedicated Power Control PWM (PCPWM) with hardware fault inputs (vs PIC18F4320-I/PT)
- Same package, same peripheral set, doubled flash for firmware growth (vs PIC18F4431-I/PT)
- QFN-44 footprint option with identical silicon (vs PIC18F4331-I/ML)
Design Notes
Estimated: Decoupling must follow Microchip's PIC18F reference layout. Place one 100 nF X7R ceramic capacitor within 5 mm of each VDD/AVDD pin, plus one bulk 10 uF tantalum or ceramic capacitor on the main VDD rail. The AVDD analog supply should be filtered with a ferrite bead from VDD, or sourced from a separate low-noise LDO if the digital supply is shared with switching converters. Failure to decouple the AVDD pin can introduce noise into the 10-bit A/D readings, degrading current-sense accuracy in motor control loops.
Route the ICSP signals PGC (RB6), PGD (RB7), and MCLR (pin 43) as short, well-isolated traces to a 6-pin RJ-11 or 6-pin PICkit header. Keep PGC and PGD routed as a differential pair to minimize skew and reject noise. Place a 4.7 kohm pull-up on MCLR. If RB6/RB7 are used as GPIO in the application, ensure the firmware disables the ICD/ICSP module in user code so the programming signals do not interfere with normal operation.
The Power Control PWM module requires explicit configuration of the PWM period register PTPER, duty cycle registers PDC, and dead-band delay registers DTCON. Forgetting to enable the PCPWM module via the PIE/PSTRT bits leaves the PWM outputs floating - never assume the default configuration. The fault inputs (FLTA, FLTB) must be configured with the correct polarity and response mode before driving the half-bridge, otherwise a fault event cannot disable the PWM outputs and shoot-through can occur in the power stage.
The 44-pin TQFP-44 (PT) package has theta_JA of approximately 50-60 C/W on a 4-layer JEDEC test board, depending on copper area. At 40 MHz CPU clock with all peripherals active, the MCU dissipates around 0.5-1 W, which is well within thermal limits. Estimated: worst-case operating junction temperature with TJ = TA + PD x theta_JA = 85 + 1 x 55 = 140 C, which exceeds the 125 C commercial maximum. For continuous high-temperature operation above 70 C ambient, either reduce CPU clock to 20 MHz or add a small copper pour under the exposed pad (TQFP-44 has no exposed pad - rely on top-layer copper area only).
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial temperature grade (-40 to +85 C). Not AEC-Q100 qualified - automotive designs should use AEC-Q100 qualified PIC18F alternatives or this part with extended qualification testing.