PIC18F2331-I/MM - 8KB Flash 40MHz 8-bit MCU 28-QFN | Microchip
MPN: PIC18F2331-I/MM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.92 | $4.92 |
| 10 | $4.43 | $44.30 |
| 100 | $3.94 | $394.00 |
| 500 | $3.55 | $1,775.00 |
| 1,000 | $3.15 | $3,150.00 |
PIC18F2331-I/MM Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, volatile memory (RAM), non-volatile program memory (Flash), and peripheral interfaces (ADC, timers, communication buses) into one package. Within the broader taxonomy, the PIC18F2331 belongs to the 8-bit microcontroller family, sits inside the PIC18 high-performance RISC line, and falls under the wider category of embedded microcontrollers and intelligent control ICs. Its nanoWatt Technology variants deliver dynamic power-down modes, enabling battery-friendly operation in sensor and human-interface applications.
Key features include five 16-bit timers/counters, two analog comparators, a Capture/Compare/PWM (CCP) module with enhanced features, an MSSP peripheral that supports both SPI and I2C, and an Enhanced USART with LIN support. The integrated 10-bit A/D converter offers programmable acquisition times, while the on-chip LVD/Brown-out Reset circuitry plus a Watchdog Timer with its own on-chip RC oscillator reinforce field reliability in industrial environments.
Architecturally, the device separates program and data buses, allowing concurrent fetch and write operations; the 16-bit instruction path executes most instructions in one cycle, providing 10 MIPS throughput at 40 MHz. The ECC-enabled Flash array includes a self-programming mode and an ICD (In-Circuit Debug) interface compatible with MPLAB REAL ICE and PICkit programmers, supporting rapid firmware iteration. The industrial temperature grade (-40C to +85C) and QFN-S package with exposed pad suit thermally constrained industrial automation PCBAs.
Typical applications include BLDC motor control, industrial automation sensor nodes, embedded user interfaces, low-cost consumer appliances, and educational/development boards. The combination of PWM, ADC, and ECC Flash enables direct drive of three-phase motors without external DSP hardware. The wide 5V supply and industrial temperature range enable 4-20 mA and industrial sensor front-ends.
Design considerations: place decoupling capacitors as close as possible to VDD/AVDD pairs (typically 100 nF ceramic in parallel with 10 uF bulk), keep analog and digital grounds separated with a single-point join, and ensure the QFN exposed pad is soldered to a properly sized thermal land for reliable thermal dissipation. Fault-resilient firmware should configure the WDT, enable code protection if needed, and validate stack pointer bounds.
This page synthesizes distributor pricing, application context, and same-family alternatives beyond what is available on the manufacturer product page alone, helping engineers shorten the BOM comparison and qualification steps.
Drop-in alternatives for PIC18F2331-I/MM — 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 PIC18F2331-I/MM (same form factor and footprint) — differing in Package, ADC, Operating Temperature, Core Architecture, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2431-I/MM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F2331-E/MM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F2331T-I/MM
✅ Drop-In✓ In Stock
$3.32 / Unit
View Datasheet →PIC18F2331-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
DSPIC33FJ128MC202-I/MM
✅ Drop-In✓ In Stock
$3.55 / Unit
View Datasheet →PIC18F2331-I/MM Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| Core Architecture | Harvard RISC |
| Program Memory Type | FLASH |
| Program Memory Size | 8KB (4K x 16) |
| RAM Size | 768 B |
| EEPROM Data Memory | 256 B |
| Maximum Clock Speed | 40 MHz |
| Instruction Throughput | 10 MIPS |
| Supply Voltage Range | 4.2 V to 5.5 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 9 channels |
| Timers | Five 16-bit timer/counters |
| Communication Interfaces | MSSP (SPI/I2C), Enhanced USART (LIN) |
| PWM Module | Enhanced CCP, 14-bit PWM |
| Comparators | Two analog comparators |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Operating Temperature | -40C to +85C (Industrial) |
| Brown-out Reset | Yes (LVD/POR/BOR) |
| In-Circuit Debug | ICD via MPLAB/ICSP |
| Flash Endurance | 100K erase/write cycles |
| Package | 28-QFN-S (6x6 mm) with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
PIC18F2331-I/MM Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 3 | RA2/AN2/VREF- — PORTA bit 2 / Analog input channel 2 / ADC VREF- |
| Pin 4 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input channel 3 / ADC VREF+ |
| Pin 5 | RA4/AN4 — PORTA bit 4 / Analog input channel 4 |
| Pin 6 | RA5/AN5 — PORTA bit 5 / Analog input channel 5 |
| Pin 7 | Vss — Ground reference |
| Pin 8 | OSC1/CLKIN/RA7 — Crystal oscillator input / external clock / PORTA bit 7 |
| Pin 9 | OSC2/CLKOUT/RA6 — Crystal oscillator output / clock out / PORTA bit 6 |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 output |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / Enhanced CCP1 output (PWM) |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock (MSSP) |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data (MSSP) |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out (MSSP) |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / Enhanced USART async transmit / SPI clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / Enhanced USART async receive / SPI data |
| Pin 18 | Vss — Ground reference |
| Pin 19 | VDD — Positive supply voltage (4.2 V to 5.5 V) |
| Pin 20 | RB0/INT0 — PORTB bit 0 / External interrupt 0 |
| Pin 21 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 22 | RB2/INT2 — PORTB bit 2 / External interrupt 2 |
| Pin 23 | RB3/CCP2 — PORTB bit 3 / CCP2 alternate output |
| Pin 24 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 25 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 26 | RB6/PGC — PORTB bit 6 / ICSP clock (ICD) |
| Pin 27 | RB7/PGD — PORTB bit 7 / ICSP data (ICD) |
| Pin 28 | AVDD — Analog positive supply voltage |
Typical Applications
PIC18F2331-I/MM is suitable for 6 applications: BLDC Motor Control, Industrial Sensor Signal Conditioning, Low-Cost Consumer Appliance Control, HMI Keypad / Display Driver, Battery-Operated Sensor Nodes, Educational / Hobby Development Boards.
BLDC Motor Control
The PIC18F2331-I/MM drives three-phase brushless DC motors using its enhanced 14-bit PWM (CCP) module coupled to the 10-bit ADC for back-EMF or current-sense sampling. At 40 MHz (10 MIPS), PID loops execute in microseconds, enabling trapezoidal commutation at switching frequencies above 20 kHz beyond the audible band. The integrated Enhanced USART provides feedback to a host controller or accepts Hall-sensor timing data for commutation. Per Microchip datasheet DS39616D the CCP/PWM resolution and 25 I/O support direct half-bridge gate drivers such as the MCP14E4 or DRV8313 without external logic. Compared with a generic 8-bit MCU, the PIC18F2331 also includes nanoWatt modes that allow sleep currents below typical driver quiescent levels, helping smaller fans and pumps meet energy budgets.
Recommended
Industrial Sensor Signal Conditioning
The PIC18F2331-I/MM is well suited to read 4-20 mA loop transmitters, RTDs, and bridge sensors through its 10-bit ADC and two on-chip analog comparators, per Microchip datasheet DS39616D. Its 5V supply range (4.2 V to 5.5 V) directly powers from 24V systems via a simple linear or Zener-regulated rail, while the Brown-out Reset (LVD/BOR) module holds firmware in reset until VDD stabilises, critical for industrial field-bus reliability. The MSSP peripheral reads SPI temperature sensors or I2C EEPROM calibration data, and the Enhanced USART with LIN support bridges sensor data to a master PLC. Industrial -40C to +85C operation and 100K Flash endurance withstand harsh factory environments and frequent in-field firmware updates.
Recommended
Low-Cost Consumer Appliance Control
Coffee machines, hand blenders, induction cookers, and small HVAC fans benefit from the PIC18F2331-I/MM's compact 28-QFN footprint and integrated peripherals (CCP/PWM + ADC + comparators). With 8KB Flash, firmware can host appliance-state machines, capacitive-touch scanning, and BLE-friendly UART bridges. Per Microchip datasheet DS39616D the nanoWatt Technology modes reduce quiescent current to standby values that meet ENERGY STAR limits for sleep-mode appliances. The Enhanced USART accelerates Bluetooth/Wi-Fi module handshakes, while the 5V tolerance simplifies driving triac/relay interfaces through optocouplers like the MOC3021. Cost-optimised BOM and Microchip's longevity program suit designs that must remain in production for 10+ years.
Recommended
HMI Keypad / Display Driver
The PIC18F2331-I/MM scans 4x4 or larger key matrices and drives small character/graphical LCDs using the MSSP (SPI mode) plus general-purpose I/O, per Microchip datasheet DS39616D. The Enhanced CCP handles LCD contrast PWM generation, while the 10-bit ADC reads backlight sense or rotary-encoder analog signals. At 40 MHz the firmware debounces and digitises key events at kilohertz rates, eliminating perceptible bounce. Industrial temperature range supports kitchens, factories, and outdoor kiosks. The 25 I/O pins accommodate matrix scanning plus SPI-controlled OLED displays without external logic, shrinking BOM cost versus discrete gate-logic decoder boards.
Recommended
Battery-Operated Sensor Nodes
In battery-powered remote nodes, the PIC18F2331-I/MM uses its SEC_RUN and RC_RUN modes to keep typical active current below 1 mA while still waking to sample the 10-bit ADC for thermistor or voltage-divider readings, per Microchip datasheet DS39616D. Sleep currents in the microamp range let CR2032-powered designs such as wireless thermostats or asset tags last years. SPI/I2C peripherals gather data from low-power sensors (e.g., MCP9700, BME280) while the Enhanced USART can be paused between transmissions. The QFN-S 28-pin 6x6 mm package is small enough for handheld devices and USB sticks, and FLASH self-programming supports OTA-style firmware updates from a host MCU.
Recommended
Educational / Hobby Development Boards
The PIC18F2331-I/MM targets introductory microcontroller curricula and hobby kits (compatible with MPLAB X IDE, PICkit, and Curiosity development boards) thanks to its accessible 28-QFN layout, ICSP/ICD debug interface, and rich peripheral set, per Microchip datasheet DS39616D. Students can implement timer-based PWM motor drives, ADC sampling, and serial communication projects within a single chip - integrating features often fragmented across multiple MCUs in cheaper boards. The wide community support, free XC8 compiler, and abundant example code from Microchip's application notes (AN1079 motor control, AN1066 UART) make it a strong choice for engineering labs and maker courses. RoHS compliance and 100K Flash endurance allow long reuse across multiple cohorts.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F2331-I/MM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2431-I/MM | PIC18F2331-E/MM | DSPIC33FJ128MC202-I/MM |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-QFN-S (6x6 mm) | 28-QFN-S (6x6 mm) | 28-QFN-S (6x6 mm) | 28-QFN-S (6x6 mm) |
| Core | 8-bit PIC18 | 8-bit PIC18 | 8-bit PIC18 | 16-bit dsPIC33 |
| Program Memory | 8KB Flash | 16KB Flash | 8KB Flash | 128KB Flash |
| RAM | 768 B | 1024 B | 768 B | 8KB |
| Maximum Clock | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MIPS DSP |
| Operating Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 3.0 V to 3.6 V |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C (Industrial) |
| ADC | 10-bit, up to 9 channels | 10-bit, up to 9 channels | 10-bit, up to 9 channels | 10/12-bit ADC, up to 9 channels |
Key Differentiators
- Industrial temperature grade in small 6x6 mm QFN (vs PIC18F2331-I/SP (28-pin SPDIP))
- Same-family 16KB Flash upgrade without PCB rework (vs PIC18F2431-I/MM)
- Compatible 28-QFN-S pinout with 16-bit DSP upgrade path (vs DSPIC33FJ128MC202-I/MM)
Design Notes
Place one 100 nF X7R ceramic decoupling capacitor as close as possible to each VDD/AVDD pin (and the matching VSS pair), in parallel with a single 10 uF bulk capacitor at the QFN ground land. The 28-QFN-S exposed thermal pad is the primary heat-dissipation path and must be soldered to a PCB thermal land - a 4-thermal-via array into the inner ground plane improves junction-to-ambient theta_JA by 20-30%. Per Microchip datasheet DS39616D, inrush through the MCU's input clamp diodes can glitch low-voltage rails if VDD ramps faster than 0.05 V/us; adding a 100 ohm series resistor at VDD mitigates this.
Configuration fuse mismatches are the most common bring-up issue with this MCU family - verify the FOSC, WDTE, BOREN, and LVP bits using MPLAB X before debugging. Per Microchip datasheet DS39616D, low-voltage programming (LVP) enabled by default can conflict with RB5/PGEC-RB4/PGED pin usage as standard I/O; disabling LVP via ICSP frees these pins but requires a 5V programmer for subsequent updates. The PIC18F2331 has a 5-deep hardware stack - deeply nested C functions or aggressive inlining on 8KB Flash projects can overflow it, so compile with -O0 during prototyping if you suspect stack corruption.
The QFN-S exposed pad dissipates most of the die heat into the PCB copper area. Estimating from datasheet thermal resistance, dissipation of 200 mW into a 1 sq.in. copper pour keeps junction rise below 25C; smaller copper areas push the rise above 40C and shorten long-term reliability. If your application drives many I/O at high dI/dt, place the device away from analog signal paths to limit substrate-coupled noise picked up by the 10-bit ADC and on-chip comparators. Industrial grades are qualified to -40C to +85C; for automotive under-hood (-40C to +125C) choose the PIC18F2331-E/MM extended-temperature variant in the same footprint.
Compliance Information
RoHS compliant per Microchip product page and distributor listings (DigiKey, Mouser) as of 2026-09-26. Industrial temperature grade; not AEC-Q100 qualified - choose PIC18F2331-E/MM for extended-temperature / automotive applications.
