PIC18F66K40-I/MR - 64KB Flash 8-bit MCU 64-VQFN | Microchip
MPN: PIC18F66K40-I/MR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.0862 | $4.09 |
| 10 | $3.85 | $38.50 |
| 100 | $3.45 | $345.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.68 | $2,680.00 |
PIC18F66K40-I/MR Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory (Flash), working memory (RAM), and integrated peripherals. The PIC18F family sits in Microchip's 8-bit portfolio, balancing computational performance with low power consumption. The K40 sub-family adds XLP technology, enabling nanoWatt sleep currents for battery-powered designs.
Key features include 64KB Flash program memory, 4KB RAM, 1KB EEPROM, 64MHz operation, up to 12-bit ADC, multiple communication peripherals (UART, SPI, I2C), Core Independent Peripherals such as Configurable Logic Cells (CLC), Complementary Waveform Generator (CWG), and Windowed Watchdog Timer (WWDT). The device operates from 2.3V to 5.5V, with some variants supporting 1.8V minimum for low-voltage applications.
The PIC18F66K40 uses a RISC Harvard-architecture CPU with a 16-bit instruction word and 8-bit data path. Its CIPs (Core Independent Peripherals) allow hardware-based state machines without CPU intervention, reducing firmware complexity and enabling deterministic real-time behavior. The 64-VQFN package integrates a thermal pad for improved heat dissipation in space-constrained designs.
Typical applications include industrial control, IoT sensor nodes, consumer electronics, automotive body controllers, home automation, and low-power wireless sensor hubs. The XLP feature set makes it especially suitable for battery-backed or energy-harvesting designs.
Design consideration: Use the MPLAB X IDE with XC8 compiler. Ensure decoupling capacitors (100nF + 10uF) are placed close to VDD pins, and connect the exposed thermal pad to a ground plane for thermal management.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the manufacturer datasheet alone, providing unique value for engineers selecting the PIC18F66K40-I/MR.
Drop-in alternatives for PIC18F66K40-I/MR — 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 PIC18F66K40-I/MR (same form factor and footprint) — differing in Package, ADC, Core Architecture, Core Independent Peripherals, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F65K40-I/MR
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →PIC18LF66K40-I/MR
✅ Drop-In✓ In Stock
$2.81 / Unit
View Datasheet →PIC18F66K40-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F66K40-E/MR
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$3.18 / Unit
View Datasheet →PIC18F66K40T-I/MR
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.46 / Unit
View Datasheet →PIC18F66K40-I/MR Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 8-bit RISC |
| Program Memory (Flash) | 64 KB (32K x 16) |
| RAM | 4 KB |
| EEPROM | 1 KB |
| Maximum CPU Speed | 64 MHz |
| Operating Voltage | 2.3 V to 5.5 V |
| I/O Pins | 60 (approx.) |
| Package | 64-pin VQFN (9x9 mm) with exposed thermal pad |
| Temperature Range (Industrial) | -40C to +85C |
| Mounting Type | Surface Mount |
| Low-Power Technology | XLP (eXtreme Low Power) |
| RoHS Status | Compliant |
| Core Independent Peripherals | CLC, CWG, WWDT, CRC, DSM, NCO |
PIC18F66K40-I/MR Pin Configuration
| Pin 1 | RA0 — GPIO / analog input |
| Pin 2 | RA1 — GPIO / analog input |
| Pin 3 | RA2 — GPIO / analog input |
| Pin 4 | RA3 — GPIO / analog input |
| Pin 5 | RA4 — GPIO / analog input |
| Pin 6 | RA5 — GPIO / analog input |
| Pin 7 | RA6 — GPIO / analog input |
| Pin 8 | RA7 — GPIO / analog input |
| Pin 9 | VSS — Ground |
| Pin 10 | VDD — Positive supply voltage |
| Pin 11 | RB0 — GPIO / interrupt-on-change |
| Pin 12 | RB1 — GPIO / interrupt-on-change |
| Pin 13 | RB2 — GPIO / interrupt-on-change |
| Pin 14 | RB3 — GPIO / interrupt-on-change |
| Pin 15 | RB4 — GPIO / interrupt-on-change |
| Pin 16 | RB5 — GPIO / interrupt-on-change |
| Pin 17 | RB6 — GPIO / interrupt-on-change / ICD PGC |
| Pin 18 | RB7 — GPIO / interrupt-on-change / ICD PGD |
| Pin 19 | RC0 — GPIO / analog input |
| Pin 20 | RC1 — GPIO / analog input |
| Pin 21 | RC2 — GPIO / analog input |
| Pin 22 | RC3 — GPIO / analog input |
| Pin 23 | RC4 — GPIO / analog input |
| Pin 24 | RC5 — GPIO / analog input |
| Pin 25 | RC6 — GPIO / analog input |
| Pin 26 | RC7 — GPIO / analog input |
| Pin 27 | VSS — Ground |
| Pin 28 | VDD — Positive supply voltage |
| Pin 29 | RD0 — GPIO |
| Pin 30 | RD1 — GPIO |
| Pin 31 | RD2 — GPIO |
| Pin 32 | RD3 — GPIO |
| Pin 33 | RD4 — GPIO |
| Pin 34 | RD5 — GPIO |
| Pin 35 | RD6 — GPIO |
| Pin 36 | RD7 — GPIO |
| Pin 37 | RE0 — GPIO |
| Pin 38 | RE1 — GPIO |
| Pin 39 | RE2 — GPIO |
| Pin 40 | RE3 — GPIO |
| Pin 41 | VSS — Ground |
| Pin 42 | VDD — Positive supply voltage |
| Pin 43 | RF0 — GPIO / analog input |
| Pin 44 | RF1 — GPIO / analog input |
| Pin 45 | RF2 — GPIO / analog input |
| Pin 46 | RF3 — GPIO / analog input |
| Pin 47 | RF4 — GPIO / analog input |
| Pin 48 | RF5 — GPIO / analog input |
| Pin 49 | RF6 — GPIO / analog input |
| Pin 50 | RF7 — GPIO / analog input |
| Pin 51 | RG0 — GPIO |
| Pin 52 | RG1 — GPIO |
| Pin 53 | RG2 — GPIO |
| Pin 54 | RG3 — GPIO |
| Pin 55 | RG4 — GPIO |
| Pin 56 | RG5 — GPIO |
| Pin 57 | RG6 — GPIO |
| Pin 58 | RG7 — GPIO |
| Pin 59 | VSS — Ground |
| Pin 60 | VDD — Positive supply voltage |
| Pin 61 | RH0 — GPIO / analog input |
| Pin 62 | RH1 — GPIO / analog input |
| Pin 63 | RH2 — GPIO / analog input |
| Pin 64 | RH3 — GPIO / analog input |
Typical Applications
PIC18F66K40-I/MR is suitable for 7 applications: Industrial Sensor Interface, IoT Edge Sensor Node, Consumer Home Appliance Control, Automotive Body Control Module, Medical Monitoring Device, Smart Energy Meter, HMI Touch Interface.
Industrial Sensor Interface
The PIC18F66K40-I/MR excels in industrial sensor interface applications due to its 12-bit ADC, multiple communication peripherals (UART/SPI/I2C), and XLP low-power features. With 64KB Flash and 4KB RAM, it can run MODBUS RTU protocol stacks while managing multiple analog and digital sensors. The 64-pin VQFN package provides ample I/O for connecting to temperature, pressure, and flow sensors simultaneously, while the extended industrial temperature range (-40C to +85C) ensures reliable operation in factory environments.
Recommended
IoT Edge Sensor Node
For battery-powered IoT edge devices, the PIC18F66K40-I/MR's XLP technology delivers nanoWatt sleep currents, enabling multi-year battery life. Its 64KB Flash accommodates LoRaWAN or BLE firmware stacks, while the 4KB RAM handles sensor buffering and encryption. The 2.3V-5.5V operating range supports direct connection to Li-ion or 3.3V regulated supplies. CIPs (CLC, WWDT) provide hardware-based sensor monitoring without waking the CPU, dramatically reducing average power consumption.
Recommended
Consumer Home Appliance Control
The PIC18F66K40-I/MR is ideal for consumer home appliance control boards including washing machines, microwave ovens, and HVAC controllers. Its 64KB Flash stores user interface state machines and fault logs, while the CWG peripheral drives motor control PWM signals directly. The integrated CRC and WWDT peripherals provide functional safety features required by IEC 60730 household appliance standards, and the 64-VQFN package fits compact PCB layouts behind control panels.
Recommended
Automotive Body Control Module
For non-safety-critical automotive body electronics (interior lighting, seat controls, door modules), the PIC18F66K40-I/MR provides robust peripheral integration. Its multiple PWM outputs drive LED drivers and small motors, while LIN-compatible UART interfaces connect to body networks. Although this part is industrial-grade (-40C to +85C), the extended variant supports +125C operation. The 64KB Flash comfortably hosts CAN/LIN protocol stacks plus application logic.
Recommended
Medical Monitoring Device
The PIC18F66K40-I/MR suits portable medical monitoring devices such as pulse oximeters, glucose meters, and digital thermometers. Its low-power XLP features extend battery life in handheld applications, while the 12-bit ADC provides sufficient resolution for biosignal acquisition. The 4KB RAM accommodates signal buffering and display refresh. Although not medical-grade qualified, it serves well in consumer health devices where IEC 60601 is not required.
Recommended
Smart Energy Meter
For smart electricity, water, or gas meters, the PIC18F66K40-I/MR combines the computational power needed for energy calculation algorithms with the low-power features required for battery-backed metering. Its 64KB Flash stores metering firmware and calibration constants in EEPROM, while the 12-bit ADC measures sensor outputs from current transformers or flow sensors. The MSSP peripheral supports SPI-based metrology ICs, and the RTC capability enables time-of-use billing functions.
Recommended
HMI Touch Interface
The PIC18F66K40-I/MR powers small HMI (Human-Machine Interface) panels with TFT displays and touch buttons in industrial equipment. Its 64KB Flash hosts display drivers and menu state machines, while the CLC peripherals implement capacitive touch sensing without CPU load. The 64-pin VQFN package provides sufficient I/O for display parallel interfaces and multiple input buttons, and the 64MHz speed enables smooth screen updates without flicker.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F66K40-I/MR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F65K40-I/MR | PIC18LF66K40-I/MR | PIC18F66K40-I/PT | PIC18F66K40-E/MR | PIC18F66K40T-I/MR |
|---|---|---|---|---|---|---|
| Package | 64-VQFN (9x9) | 64-VQFN (9x9) - same | 64-VQFN (9x9) - same | 64-TQFP (10x10) - different footprint | 64-VQFN (9x9) - same | 64-VQFN (9x9) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64 KB | 32 KB (-50%) | 64 KB (same) | 64 KB (same) | 64 KB (same) | 64 KB (same) |
| RAM | 4 KB | 2 KB (-50%) | 4 KB (same) | 4 KB (same) | 4 KB (same) | 4 KB (same) |
| Maximum Frequency | 64 MHz | 64 MHz (same) | 64 MHz (same) | 64 MHz (same) | 64 MHz (same) | 64 MHz (same) |
| Operating Voltage | 2.3V to 5.5V | 2.3V to 5.5V (same) | 1.8V to 3.6V (lower min) | 2.3V to 5.5V (same) | 2.3V to 5.5V (same) | 2.3V to 5.5V (same) |
| Temperature Range | -40C to +85C (Industrial) | -40C to +85C (same) | -40C to +85C (same) | -40C to +85C (same) | -40C to +125C (Extended) | -40C to +85C (same) |
| Core Independent Peripherals | CLC, CWG, WWDT, CRC, DSM, NCO | Same CIP set | Same CIP set | Same CIP set | Same CIP set | Same CIP set |
Key Differentiators
- Higher Flash density than PIC18F65K40 (vs PIC18F65K40-I/MR)
- Standard voltage range vs low-voltage LF variant (vs PIC18LF66K40-I/MR)
- Compact VQFN footprint with thermal pad (vs PIC18F66K40-I/PT (TQFP package))
Design Notes
The PIC18F66K40-I/MR has multiple VDD/VSS pin pairs that must all be connected to ensure proper operation. Place a 100nF ceramic decoupling capacitor close to each VDD pin and a bulk 10uF capacitor near the IC. Use a ground plane for the VSS connections to minimize noise. In XLP sleep modes, current consumption drops to nanoAmpere levels - ensure no floating inputs and configure unused pins as outputs to minimize leakage.
The 64-VQFN package features an exposed thermal pad (EP) on the underside that MUST be soldered to the PCB ground plane for proper thermal dissipation. Without proper EP soldering, junction temperature can rise significantly under high I/O switching loads. Use thermal vias in a 3x3 grid pattern beneath the EP to conduct heat to inner PCB layers. The 9x9 mm VQFN provides better thermal performance than equivalent TQFP packages.
Route the ICSP (In-Circuit Serial Programming) pins RB6/PGC and RB7/PGD as short, direct traces to the programming connector header to avoid programming failures. Keep analog signals (ADC inputs, VREF+) routed away from high-frequency digital lines (PWM, clock outputs) to minimize crosstalk. The 0.65mm pitch of the VQFN package requires fine-pitch PCB manufacturing (4/4 mil trace/space minimum recommended).
Common pitfalls when using the PIC18F66K40-I/MR: (1) Forgetting to configure the CONFIG words in source code - the device will not operate correctly with default configuration; (2) Not enabling the WDT or WWDT during development, causing firmware hangs to be undetectable; (3) Using the internal oscillator without calibration - the HFINTOSC can vary ±5% across temperature; (4) Driving LED or relay loads directly from GPIO pins without current-limiting resistors or driver transistors.
For optimal EMI performance, place the MCU crystal or external clock components within 5mm of the OSC1/OSC2 pins. Use a guard ring around the crystal traces connected to ground. If using the internal HFINTOSC, no external crystal is required but the PLL configuration must follow the datasheet guidance to achieve 64MHz operation. Keep switching regulator components away from the MCU analog sections to prevent conducted noise on ADC readings.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - choose automotive-grade PIC18 variants for vehicle applications. Lead-free and halogen-free packaging.
