PIC18LF2331T-I/MM - 8-bit 40MHz MCU, 8KB Flash, 22 I/O | Microchip
MPN: PIC18LF2331T-I/MM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.18 | $5.18 |
| 10 | $4.68 | $46.80 |
| 100 | $4.1 | $410.00 |
| 500 | $3.62 | $1,810.00 |
| 1,000 | $3.18 | $3,180.00 |
PIC18LF2331T-I/MM Overview
An 8-bit PIC microcontroller is a Harvard-architecture RISC device that executes one instruction per clock cycle (except branches) and provides deterministic interrupt latency, which is essential in real-time embedded control. The PIC18 family sits within Microchip's broader 8-bit portfolio, alongside PIC10, PIC12, PIC16 and the newer PIC18 K-series, and forms the upper performance tier with the largest instruction set (77 instructions) and the richest peripheral mix. These MCUs typically replace discrete logic and analog circuitry in cost-sensitive industrial and consumer products by integrating CPU, non-volatile program memory, data EEPROM, RAM and configurable I/O on a single die.
Key features of the PIC18LF2331T-I/MM include an industrial temperature range of -40C to +85C, low-power sleep modes with nanoWatt technology, an enhanced flash program memory rated for typical endurance of 100K erase/write cycles, and on-chip data EEPROM of 256 bytes. The 28-QFN-S package reduces board footprint versus 28-pin SOIC while still exposing 22 general-purpose I/O lines and supports up to 10 MHz operation at 2.0V and 40 MHz at 4.2V-5.5V.
The device uses a 16-bit instruction word with a 21-bit program counter that can address 2 MB of linear program space, plus a hardware multiplier and 8x8 single-cycle hardware multiply. Peripheral integration includes up to five CCP/PWM channels, two analog comparators, two enhanced USART modules and a 10-bit A/D converter with up to 9 channels, enabling compact BLDC motor control, UPS, power-supply feedback and instrumentation front-ends.
Typical applications include sensorless and sensored BLDC/PMSM motor drives, switched-mode power supply digital feedback, industrial process control, HVAC fan control, small appliance motor control and battery chargers. Its wide operating voltage also makes it a fit for portable measurement and consumer appliances.
When designing with this part, ensure VDDCORE/VDD decoupling uses 100 nF and bulk caps placed within 5 mm of the pins, that unused I/O are configured as outputs low to minimize shoot-through current, and that the in-circuit serial programming (ICSP) pins (PGC/PGD) are accessible for firmware updates.
This page consolidates distributor pricing, drop-in alternatives drawn from Microchip's PIC18LF2331/2431 family and the broader PIC18F low-voltage portfolio, plus practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18LF2331T-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 PIC18LF2331T-I/MM (same form factor and footprint) — differing in Operating Temperature, Package, ADC, I/O Pins, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF2431T-I/MM
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF2331T-I/ML
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC18F2331-I/MM
✅ Drop-In✓ In Stock
$3.15 / Unit
View Datasheet →PIC18F2331-I/SP
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF2331-I/SO
✅ Drop-In✓ In Stock
$4.88 / Unit
View Datasheet →PIC18LF4331T-I/MM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF2539T-I/MM
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LF2331T-I/MM Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC18F |
| CPU Core | PIC18 |
| Program Memory Size | 8 KB (4K x 16) Flash |
| RAM Size | 768 bytes |
| EEPROM Size | 256 bytes |
| Maximum CPU Frequency | 40 MHz |
| Operating Voltage Range (LF) | 2.0 V to 5.5 V |
| I/O Pins | 22 |
| ADC | 10-bit, up to 9 channels |
| PWM / CCP | 5 CCP/PWM channels |
| Communication | Enhanced USART, MSSP (SPI/I2C) |
| Operating Temperature | -40C to +85C (Industrial, 'I') |
| Package | 28-pin QFN-S (6x6 mm) |
| Mounting Type | Surface Mount |
| MSL Level | MSL1 |
| RoHS Status | Compliant |
PIC18LF2331T-I/MM Pin Configuration
| Pin 1 | MCLR/RA5 — Master Clear (reset) input / RA5 GPIO |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / ADC VREF+ |
| Pin 6 | RA4/AN4 — PORTA bit 4 / analog input 4 |
| Pin 7 | VDD — Positive supply (2.0V-5.5V for LF variant) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/RA7 — Crystal oscillator input / RA7 GPIO |
| Pin 10 | OSC2/RA6 — Crystal oscillator output / RA6 GPIO |
| Pin 11 | RC0/T1OSO — PORTC bit 0 / Timer1 oscillator output |
| Pin 12 | RC1/T1OSI — PORTC bit 1 / Timer1 oscillator input |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / Capture-Compare-PWM 1 |
| Pin 14 | RC3/CCP2 — PORTC bit 3 / Capture-Compare-PWM 2 |
| Pin 15 | RC4/CCP3 — PORTC bit 4 / Capture-Compare-PWM 3 |
| Pin 16 | RC5/CCP4 — PORTC bit 5 / Capture-Compare-PWM 4 |
| Pin 17 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 18 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 19 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 20 | RB3/CCP5 — PORTB bit 3 / Capture-Compare-PWM 5 |
| Pin 21 | RB4 — PORTB bit 4 |
| Pin 22 | RB5/PGM — PORTB bit 5 / low-voltage ICSP programming |
| Pin 23 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 24 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 25 | RC6/TX — PORTC bit 6 / EUSART transmit |
| Pin 26 | RC7/RX — PORTC bit 7 / EUSART receive |
| Pin 27 | VDD — Positive supply (second VDD pin) |
| Pin 28 | VSS — Ground reference (second VSS pin) |
| Pin EP | EP — Exposed thermal pad - tie to VSS |
Typical Applications
PIC18LF2331T-I/MM is suitable for 7 applications: Sensorless BLDC Motor Control, Switched-Mode Power Supply Digital Feedback, HVAC Fan and Blower Control, Portable Battery-Powered Measurement, Small Appliance Motor Control (Food Processors, Mixers), Industrial Process Control and Instrumentation, Sensorless Bidirectional Pump Control.
Sensorless BLDC Motor Control
The PIC18LF2331T-I/MM is purpose-built for sensorless brushless DC motor control thanks to its integrated Motion Feedback Module (MFM) and 5-channel CCP/PWM. The MFM samples back-EMF zero-cross events and the 10-bit ADC converts phase currents while the PWM module drives a 3-phase inverter at up to 40 MIPS. The 2.0V-5.5V Vdd range enables direct operation from a single Li-ion cell via a boost converter, removing the need for a 5V rail. Code is portable across the PIC18F2331 family, so engineers can scale to PIC18F4431 for higher-end 3-phase systems without rewriting the control loop.
Recommended
Switched-Mode Power Supply Digital Feedback
The PIC18LF2331T-I/MM provides digital control loop compensation for isolated and non-isolated DC-DC converters. Its 40 MIPS throughput supports average-current-mode control at 200 kHz switching frequency while the 10-bit ADC samples Vout and inductor current each switching cycle. The enhanced USART enables PMBus or UART telemetry, and the 8KB Flash holds lookup tables and PID coefficients. Compared to a pure analog UC3842 implementation, the PIC18LF2331T-I/MM adds adaptive dead-time, soft-start profiling and OVP/UVP/OCP diagnostics with no external glue logic.
Recommended
HVAC Fan and Blower Control
In HVAC variable-speed fan and blower drives, the PIC18LF2331T-I/MM directly drives a 3-phase inverter or a single-phase AC fan motor via its CCP/PWM channels. The MFM block detects rotor position from back-EMF for sensorless operation, eliminating Hall-effect sensors and reducing wiring harness cost. Industrial -40C to +85C operation tolerates rooftop unit environments, while the 28-QFN 6x6 mm footprint fits inside a 30 mm diameter motor stator assembly. The PIC18 nanoWatt technology drops idle power below 1 uA for sleep-mode standby required by EnergyStar HVAC equipment.
Recommended
Portable Battery-Powered Measurement
The PIC18LF2331T-I/MM 'LF' variant operates directly from a single Li-ion cell (3.0V-4.2V) without a boost regulator, ideal for handheld multimeters, insulation testers and clamp meters. The 10-bit ADC handles voltage, current and temperature sensing while the enhanced USART streams results to a Bluetooth or USB module. nanoWatt sleep currents below 100 nA extend battery life to >1000 hours of standby, and the 256-byte EEPROM stores calibration tables permanently. Industrial temperature grade ensures accuracy from -40C to +85C ambient.
Recommended
Small Appliance Motor Control (Food Processors, Mixers)
In food processors, blenders and stand mixers, the PIC18LF2331T-I/MM provides closed-loop torque and speed control via its MFM and PWM peripherals. The 40 MIPS core updates the PWM duty every 25 us, delivering smooth start-up ramps and current limiting that protects the universal motor from stall damage. Cost-sensitive small appliances benefit from the 28-QFN footprint that fits a 25 mm x 25 mm controller PCB, and the 8KB Flash is sufficient for sensorless back-EMF firmware plus look-up tables. The /MM tape-and-reel format supports high-volume SMT assembly lines.
Recommended
Industrial Process Control and Instrumentation
The PIC18LF2331T-I/MM supports industrial process loops requiring deterministic real-time response, such as 4-20 mA loop controllers, solenoid drivers and indicator panels. The 22 I/O pins drive multiplexed 7-segment displays and accept digital inputs from limit switches, while the 10-bit ADC reads bridge sensors for pressure or flow. The MSSP peripheral supports SPI for a 24-bit sigma-delta ADC like the MCP3551, upgrading loop resolution to 22 bits effective. The -40C to +85C industrial grade and 100K Flash endurance ensure 10+ year field life in PLC and SCADA modules.
Recommended
Sensorless Bidirectional Pump Control
The PIC18LF2331T-I/MM implements bidirectional pump control for medical infusion and metering pumps by reading back-EMF in the inactive phase to determine rotor position. The CCP/PWM channels generate complementary 20 kHz drive signals with programmable dead-time to prevent shoot-through, while the analog comparators provide hardware overcurrent protection independent of the ADC. 8KB Flash fits the state-machine firmware plus flow-vs-PWM calibration, and the 256-byte EEPROM stores per-pump trim values. Compared to a 16-bit DSP-based design, the 8-bit PIC18 core is dramatically cheaper while still meeting IEC 60601 timing requirements.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF2331T-I/MM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF2431T-I/MM | PIC18F2331-I/MM | PIC18LF4331T-I/MM | PIC18LF2539T-I/MM |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-QFN-S (6x6 mm) | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same | 28-QFN-S (6x6 mm) - same |
| Program Memory (Flash) | 8 KB | 8 KB | 8 KB | 16 KB | 24 KB |
| RAM | 768 bytes | 768 bytes | 768 bytes | 768 bytes | 1.5 KB |
| Operating Voltage | 2.0 V - 5.5 V (LF) | 2.0 V - 5.5 V (LF) | 4.2 V - 5.5 V (F only) | 2.0 V - 5.5 V (LF) | 2.0 V - 5.5 V (LF) |
| Max CPU Frequency | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS |
| I/O Pins | 22 | 24 | 22 | 22 | 22 |
| ADC Channels | 9 channels, 10-bit | 11 channels, 10-bit | 9 channels, 10-bit | 9 channels, 10-bit | 9 channels, 10-bit |
| Motion Feedback Module | Yes (1 unit) | Yes (1 unit) | Yes (1 unit) | Yes (1 unit) | Yes (2 units) |
Key Differentiators
- Integrated Motion Feedback Module for sensorless motor control (vs PIC18F2331-I/MM (standard-voltage variant))
- Low-voltage LF operation down to 2.0V (vs PIC18F2331-I/MM (standard-voltage variant))
- Same die across /MM, /ML, /SP, /SO packages (vs PIC18LF2331T-I/ML (tape-and-reel alternative))
Design Notes
Estimated: at Vdd=5.0V, 40 MHz clock, all peripherals enabled, the PIC18LF2331T-I/MM draws roughly 16-22 mA active and ~0.1 uA in sleep. Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD/VSS pin pair (pins 7/8 and 27/28 in the 28-QFN), plus a 10 uF bulk capacitor at the board supply input. Use a ferrite bead between the analog VDD and digital VDD if separating power planes. AVDD (if not bonded internally) must be tied to VDD directly; AVSS to VSS.
The 28-QFN 6x6 mm package has a thermal pad that MUST be soldered to a 5 mm x 5 mm copper pour on the PCB for both thermal dissipation and electrical ground. The exposed pad is internally bonded to VSS; connecting it to a ground plane reduces die-to-ambient thermal resistance theta_JA from ~85 C/W (no pad solder) to ~28 C/W. Maintain a 0.2 mm solder mask dam between the thermal pad and adjacent signal pads, and use a via-array (0.3 mm holes, 0.6 mm pitch) underneath the pad for heat conduction to inner ground layers.
Two common pitfalls when designing with PIC18LF2331T-I/MM: (1) The ICSP pins PGC (RB6) and PGD (RB7) are also general-purpose I/O - if pulled low at power-up the device enters ICSP mode instead of running user code. Add 10 kohm pull-ups on PGC and PGD or sequence your hardware to keep them high during reset. (2) When migrating between LF (2.0V) and F (4.2V) variants in the same design, verify the brown-out reset and low-voltage programming voltage thresholds in the configuration words; LF parts tolerate lower Vdd but need adjusted BOR settings to avoid spurious resets at 2.5V-3.0V.
The analog inputs AN0-AN4 share PORTA pins with digital I/O. To achieve 10-bit ADC accuracy, configure the TRISA register to set unused analog channels as digital outputs (not inputs) and add a 100 nF bypass on VREF+ if used. The ADC clock period TAD must be at least 1.6 us - at 40 MHz Fosc use a divide-by-16 ADC clock (Fosc/16 = 2.5 MHz, TAD = 0.4 us is too fast; use Fosc/64 = 625 kHz, TAD = 1.6 us). Acquisition time is approximately 19.7 us with 100 ohm source impedance and 5 pS sample capacitor.
Compliance Information
RoHS compliant and lead-free per Microchip product page; the 28-QFN package is Pb-free matte-tin plating. Industrial temperature grade (-40C to +85C), not AEC-Q100 qualified - for automotive motor control, choose a Q-graded PIC18 variant.
