PIC18F4685-I/P - 8-bit MCU 96KB Flash ECAN 40-PDIP | Microchip
MPN: PIC18F4685-I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.4 | $8.40 |
| 10 | $7.55 | $75.50 |
| 100 | $6.72 | $672.00 |
| 500 | $6.05 | $3,025.00 |
| 1,000 | $5.4 | $5,400.00 |
PIC18F4685-I/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program and data memory, peripherals, and I/O. The PIC18F family represents Microchip's high-performance 8-bit architecture with a 16-bit instruction word and 8-bit data path, optimized for deterministic real-time control. Within the MCU hierarchy, the PIC18F4685 sits in the ECAN-equipped automotive/industrial subgroup, adding Controller Area Network 2.0B hardware acceleration critical for in-vehicle networking, factory automation, and distributed sensor systems.
Key features include an integrated ECAN module supporting CAN 2.0B active with eight acceptance filters and three acceptance masks, an 11-channel 10-bit ADC with up to 100 ksps conversion, multiple PWM and Capture/Compare modules, and nanoWatt power-saving modes that drop quiescent current below 100 nA in sleep. Up to 36 digital I/O pins are available with interrupt-on-change capability on several ports.
The PIC18F4685 architecture uses a RISC-like instruction set with hardware multiply, an 8 × 8 single-cycle multiplier, and a 31-level hardware stack. The 40 MHz oscillator yields a 100 ns instruction cycle, making the device well-suited to time-critical control loops. On-chip in-circuit debug (ICD) and self-programmability support field upgrades via the standard 2-wire ICSP interface.
Typical applications include automotive body and powertrain ECUs, industrial CAN nodes, building automation gateways, HVAC fan/blower controllers, sensor hubs with local decision-making, and embedded control boards where a robust 8-bit core plus CAN bus simplifies system partitioning. The wide operating temperature range of -40 °C to +85 °C covers industrial and automotive interiors.
When designing with the PIC18F4685-I/P, choose the PDIP package only when through-hole assembly, easy breadboarding, or hand-prototyping is required - otherwise select the TQFP-44 (PT), QFN-44 (ML), or SOIC-40 (SP) variants for SMD production. Ensure the CAN bus is terminated with 120 Ω at each end and that the ECAN baud rate prescaler matches the oscillator frequency.
This page synthesizes distributor pricing, drop-in same-package alternatives, ICSP debug notes, and application-specific guidance not present in the bare Microchip datasheet.
Drop-in alternatives for PIC18F4685-I/P — 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 PIC18F4685-I/P (same form factor and footprint) — differing in Package, Program Memory (Flash), Operating Temperature, Core Architecture, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4680-I/P
✅ Drop-In✓ In Stock
$5.78 / Unit
View Datasheet →PIC18F4585-I/PT
✅ Drop-In✓ In Stock
$5.73 / Unit
View Datasheet →PIC18F4682-I/P
✅ Drop-In✓ In Stock
$5.3 / Unit
View Datasheet →PIC18F4525-I/PT
✅ Drop-In✓ In Stock
$4.18 / Unit
View Datasheet →PIC18F4580-I/P
✅ Drop-In✓ In Stock
$5.1 / Unit
View Datasheet →PIC18F4480-I/P
✅ Drop-In✓ In Stock
$6.62 / Unit
View Datasheet →PIC18F4515-I/P
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18F4685-I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit, 16-bit instruction word) |
| Program Memory (Flash) | 96 KB (48K x 16) |
| SRAM | 3,328 bytes |
| EEPROM | 1 KB |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Operating Voltage | 2.0 V to 5.5 V |
| I/O Pins | 36 |
| ADC | 11 x 10-bit, up to 100 ksps |
| CAN Module | ECAN 2.0B active |
| PWM Outputs | 5 (ECCP + CCP) |
| Timers | 4 (Timer0/1/2/3) |
| Communication | ECAN, USART, SPI, I2C (MSSP) |
| Package | 40-pin PDIP (600 mil) |
| Mounting Type | Through-Hole |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| ICSP / ICD | Yes (2-wire In-Circuit Serial Programming) |
| RoHS Status | Compliant |
PIC18F4685-I/P Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear (Reset) input / digital I/O |
| Pin 2 | RA0/AN0 — Digital I/O / Analog input 0 |
| Pin 3 | RA1/AN1 — Digital I/O / Analog input 1 |
| Pin 4 | RA2/AN2/VREF- — Digital I/O / Analog input 2 / ADC negative reference |
| Pin 5 | RA3/AN3/VREF+ — Digital I/O / Analog input 3 / ADC positive reference |
| Pin 6 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Pin 7 | RA5/AN4/SS/HLVDIN — Digital I/O / Analog input 4 / SPI Slave Select / High-Low Voltage Detect input |
| Pin 8 | RE0/RD/AN5 — Digital I/O / Parallel port read / Analog input 5 |
| Pin 9 | RE1/WR/AN6 — Digital I/O / Parallel port write / Analog input 6 |
| Pin 10 | RE2/CS/AN7 — Digital I/O / Parallel port chip select / Analog input 7 |
| Pin 11 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKI/RA7 — Crystal oscillator input / external clock input / digital I/O |
| Pin 14 | OSC2/CLKO/RA6 — Crystal oscillator output / clock output / digital I/O |
| Pin 15 | RC0/T1OSO/T13CKI — Digital I/O / Timer1 oscillator output / Timer1/3 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — Digital I/O / Timer1 oscillator input / Capture/Compare/PWM 2 |
| Pin 17 | RC2/CCP1 — Digital I/O / Capture/Compare/PWM 1 |
| Pin 18 | RC3/SCK/SCL — Digital I/O / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0 — Digital I/O / Parallel Slave Port bit 0 |
| Pin 20 | RD1/PSP1 — Digital I/O / Parallel Slave Port bit 1 |
| Pin 21 | RD2/PSP2 — Digital I/O / Parallel Slave Port bit 2 |
| Pin 22 | RD3/PSP3 — Digital I/O / Parallel Slave Port bit 3 |
| Pin 23 | RC4/SDI/SDA — Digital I/O / SPI data in / I2C data |
| Pin 24 | RC5/SDO — Digital I/O / SPI data out |
| Pin 25 | RC6/TX/CK — Digital I/O / USART transmit / USART clock / CAN TX |
| Pin 26 | RC7/RX/DT — Digital I/O / USART receive / USART data / CAN RX |
| Pin 27 | RD4/PSP4 — Digital I/O / Parallel Slave Port bit 4 |
| Pin 28 | RD5/PSP5 — Digital I/O / Parallel Slave Port bit 5 |
| Pin 29 | RD6/PSP6 — Digital I/O / Parallel Slave Port bit 6 |
| Pin 30 | RD7/PSP7 — Digital I/O / Parallel Slave Port bit 7 |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin 33 | RB0/INT0/FLT0 — Digital I/O / External interrupt 0 / PWM Fault input |
| Pin 34 | RB1/INT1 — Digital I/O / External interrupt 1 |
| Pin 35 | RB2/INT2/CANTX — Digital I/O / External interrupt 2 / CAN TX alternate |
| Pin 36 | RB3/INT3/CANRX — Digital I/O / External interrupt 3 / CAN RX alternate |
| Pin 37 | RB4/KBI0 — Digital I/O / Interrupt-on-change bit 0 |
| Pin 38 | RB5/KBI1/PGM — Digital I/O / Interrupt-on-change bit 1 / LVP programming |
| Pin 39 | RB6/KBI2/PGC — Digital I/O / Interrupt-on-change bit 2 / ICSP clock |
| Pin 40 | RB7/KBI3/PGD — Digital I/O / Interrupt-on-change bit 3 / ICSP data |
Typical Applications
PIC18F4685-I/P is suitable for 6 applications: Industrial CAN Node / Fieldbus Gateway, Automotive Body Control Module, HVAC Fan / Blower Controller, Building Automation Sensor Hub, Educational Microcontroller Trainer, Embedded Data Acquisition Module.
Industrial CAN Node / Fieldbus Gateway
The PIC18F4685-I/P is purpose-built for CAN 2.0B industrial networking. Its integrated ECAN module with eight acceptance filters and three acceptance masks offloads message filtering from the CPU, allowing the 10 MIPS core to focus on application logic. The 96 KB Flash fits full CANopen or DeviceNet protocol stacks, and 3,328 bytes of SRAM handles incoming CAN frames comfortably. Operating from 2.0 V to 5.5 V supports both 24 V bus-powered (post-regulator) and 3.3 V logic designs without re-spin. The 40-pin PDIP package makes this part easy to prototype and rework, which is critical for industrial gateway designs that iterate across multiple protocols.
Recommended
Automotive Body Control Module
The PIC18F4685-I/P is widely used in automotive body controllers managing lighting, door modules, mirror controls, and seat positioning. The ECAN module handles the vehicle body CAN bus, while the 11-channel 10-bit ADC reads multiple sensors (temperature, position, current) simultaneously. The 5 PWM outputs drive LED dimming, mirror actuators, and motor speed control. With industrial -40 °C to +85 °C temperature range and nanoWatt sleep modes drawing less than 100 nA, it supports always-on body networks with battery-friendly quiescent current. The 40-PDIP package simplifies early prototype builds for bench validation before transitioning to TQFP-44 for production.
Recommended
HVAC Fan / Blower Controller
The PIC18F4685-I/P drives variable-speed blower motors in HVAC systems using its ECCP module with hardware PWM and the 11-channel ADC for closed-loop speed feedback. The 40 MHz clock and 10 MIPS throughput handle real-time PID control loops with sub-millisecond update rates, while the 96 KB Flash holds complex control algorithms including soft-start, stall detection, and adaptive filtering. nanoWatt idle modes reduce quiescent current when the blower is off, supporting Energy Star efficiency targets. The 40-PDIP package is ideal for through-hole industrial controllers that must withstand vibration and high humidity in plenums and air-handler units.
Recommended
Building Automation Sensor Hub
The PIC18F4685-I/P serves as a distributed sensor hub in BACnet or Modbus building automation networks. It aggregates data from multiple sensor types via the 11-channel ADC and digital I/O, performs local threshold logic, and reports consolidated readings over CAN or USART. The 3,328 bytes of SRAM buffer incoming sensor data, while the ECAN module publishes to a central building management system. nanoWatt sleep modes extend battery life in wireless hybrid nodes that transmit periodically. The 40-PDIP form factor is preferred for retrofit installations where through-hole replacement simplifies service and field upgrades without disturbing existing wiring.
Recommended
Educational Microcontroller Trainer
The PIC18F4685-I/P is a popular choice in university and vocational training labs because the 40-pin PDIP package fits standard 0.6-inch-wide DIP sockets, the breadboard-friendly footprint simplifies student lab work, and the PIC18 architecture's orthogonal instruction set makes assembly language teaching tractable. The 96 KB Flash accommodates large student projects including CAN protocol stacks, ADC sampling exercises, and PWM motor control labs. ICSP support via the 2-wire PGC/PGD interface on RB6/RB7 allows real-time in-circuit debugging using the PICkit 5 or ICD 4, so instructors can pause execution and inspect registers during lab sessions.
Recommended
Embedded Data Acquisition Module
The PIC18F4685-I/P is well-suited for stand-alone data loggers and process monitoring modules. The 11-channel 10-bit ADC at 100 ksps samples analog inputs at rates sufficient for vibration, temperature, and pressure monitoring. The 3,328-byte SRAM acts as a circular buffer for time-stamped events, while the 96 KB Flash stores user configuration and custom calibration tables. The 1 KB EEPROM retains logged data through power cycles. ECAN enables the logger to publish events to a plant-wide SCADA network. The 40-PDIP through-hole package provides mechanical robustness in industrial cabinet installations subject to vibration and thermal cycling.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4685-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4680-I/P | PIC18F4585-I/P | PIC18F4682-I/P | PIC18F4525-I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-pin PDIP | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same |
| Program Memory (Flash) | 96 KB | 64 KB | 48 KB | 80 KB | 48 KB |
| SRAM | 3,328 bytes | 3,328 bytes | 3,328 bytes | 3,328 bytes | 3,984 bytes |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| CAN Module | ECAN 2.0B | ECAN 2.0B | CAN 1.0B | CAN 1.0B | None |
| ADC | 11 x 10-bit | 11 x 10-bit | 11 x 10-bit | 11 x 10-bit | 13 x 10-bit |
| Maximum Clock | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS | 40 MHz / 10 MIPS |
| 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 | 2.0 V to 5.5 V |
Key Differentiators
- Largest Flash in the ECAN 2.0B PIC18F 40-PDIP family (vs PIC18F4680-I/P)
- True ECAN 2.0B active with 8 acceptance filters (vs PIC18F4585-I/P)
- CAN bus + full 96 KB Flash in 40-PDIP (vs PIC18F4525-I/P)
Design Notes
The PIC18F4685-I/P requires decoupling on each VDD/VSS pair. Place a 100 nF ceramic capacitor as close as possible to each of the two VDD pins (11 and 32) and a single 10 µF tantalum or ceramic bulk capacitor near the MCU. nanoWatt sleep modes draw less than 100 nA at 2 V, so a clean supply is essential for sleep-current measurements to reflect real application draw. Avoid switching the VDD rail near the crystal oscillator pins to prevent jitter on timer1 or the ECAN baud rate clock.
The ECAN bus must be terminated with 120 Ω resistors at each physical end of the bus segment, NOT at every node. Use twisted-pair cable with characteristic impedance of 120 Ω and keep stub lengths under 30 cm. Common-mode choke and TVS protection (such as PESD1CAN) are recommended for industrial environments. The PIC18F4685-I/P CAN bit timing must be configured per the CiA 601-1 recommendation: sample point at 87.5% of the bit time for 1 Mbit/s and 80% for lower baud rates.
Three common PIC18F4685-I/P pitfalls: (1) configuring PGC/PGD on RB6/RB7 in standard I/O mode disables ICSP - always leave CONFIG bits LVP and DEBUG in default unless alternate configuration is intentional; (2) the ECAN module must be switched to configuration mode (REQOP = 100) before writing to acceptance filter registers; (3) the ADC requires the acquisition time TACQ to elapse before starting conversion - failure to wait causes reduced accuracy especially on high-impedance sources above 10 kΩ.
The PIC18F4685-I/P in 40-PDIP package has excellent thermal dissipation due to the through-hole leads. Estimated: at 40 MHz with full I/O switching (36 outputs at 20 pF each), internal dissipation is approximately 90 mW, well within the 1 W package limit. For SMD variants (TQFP-44, QFN-44), reduce switching frequency or output load to stay within the lower ~700 mW SMD thermal budget.
Compliance Information
RoHS and REACH compliance per Microchip product page. The -I/P industrial grade carries -40 °C to +85 °C rating; AEC-Q100 automotive qualification requires the dedicated -EQ or automotive suffix part numbers.
