PIC18F4685-E/P - 8-bit 40MHz MCU 96KB Flash w/ECAN | Microchip
MPN: PIC18F4685-E/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.13 | $9.13 |
| 10 | $8.45 | $84.50 |
| 100 | $7.62 | $762.00 |
| 500 | $6.85 | $3,425.00 |
| 1,000 | $6.2 | $6,200.00 |
PIC18F4685-E/P Overview
Key features include 36 digital I/O pins, 1KB of EEPROM, an integrated 10-bit ADC with multiple channels, and the enhanced ECAN controller that brings automotive-grade CAN 2.0B networking to cost-sensitive embedded designs. The wide 4.2V to 5.5V operating voltage range aligns with legacy 5V system buses, easing integration with analog front-ends and older peripherals that have not migrated to 3.3V logic.
The PIC18F4685 uses Microchip's enhanced Harvard RISC architecture with 16-bit instructions and 8-bit data, delivering approximately 10 MIPS at 40MHz. The ECAN module supports both standard and extended identifiers, multiple transmit/receive buffers, and filtering masks that reduce host CPU load. On-chip peripherals include USART, MSSP (SPI/I2C), PWM, capture/compare, and an 8-bit parallel port, providing enough flexibility for industrial control nodes without external expansion chips.
Typical applications include industrial CAN nodes, automotive body and chassis ECUs, building automation gateways, sensor data loggers, and HVAC controllers. The large 96KB flash accommodates full CANopen or DeviceNet stacks plus application firmware, and the -E temperature grade allows deployment in unconditioned enclosures.
When designing with this part, allocate adequate decoupling on VDD/AVDD pairs and follow Microchip's AN1245 layout guidelines for ECAN signal integrity. The 40-pin PDIP footprint is breadboard-friendly for prototyping, simplifying firmware bring-up before committing to a TQFP/MLF surface-mount variant.
Drop-in alternatives for PIC18F4685-E/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-E/P (same form factor and footprint) — differing in Package, ADC, Program Memory (Flash), CAN Module, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4685-I/P
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC18F4682-I/P
✅ Drop-In✓ In Stock
$5.3 / Unit
View Datasheet →PIC18F4585-E/P
✅ Drop-In✓ In Stock
$5.07 / Unit
View Datasheet →PIC18F4680-E/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F46K80-I/P
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18F4685-E/P Maximum Ratings & Electrical Characteristics
| Series | PIC 18F |
| Core | PIC18 (8-bit Harvard RISC) |
| Program Memory (Flash) | 96 KB (48K x 16) |
| Data RAM | 3.25 KB |
| EEPROM | 1 KB |
| Maximum Clock Frequency | 40 MHz |
| Instruction Set Width | 16-bit instructions, 8-bit data |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| I/O Pins | 36 |
| CAN Module | Enhanced CAN (ECAN) 2.0B |
| Communication Peripherals | ECAN, USART, MSSP (SPI/I2C) |
| Timers/PWM/Capture-Compare | Yes (multiple, see datasheet) |
| Operating Temperature | -40 C to +125 C (Extended -E grade) |
| Package | 40-pin PDIP (DIP-40) |
| Mounting Type | Through-Hole |
| MSL Level | Not Applicable (through-hole) |
| RoHS Status | Compliant (Pb-free) |
PIC18F4685-E/P Pin Configuration
| Pin 1 | MCLR/VPP/RE3 — Master Clear (reset) input / Programming voltage / Digital input only |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / Analog input / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input / ADC VREF+ |
| Pin 6 | RA4/T0CKI/C1OUT — PORTA bit 4 / Timer0 clock input / Comparator 1 output |
| Pin 7 | RA5/AN4/SS/HLVDIN/C2OUT — PORTA bit 5 / Analog input / SPI Slave Select / HLVD input / Comparator 2 output |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / Read control for parallel port / Analog input |
| Pin 9 | RE1/WR/AN6/C1OUT — PORTE bit 1 / Write control / Analog input / Comparator 1 output |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / Chip Select for parallel port / Analog input |
| Pin 11 | VDD — Positive supply voltage (5V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKI/RA7 — Oscillator input / External clock input / PORTA bit 7 |
| Pin 14 | OSC2/CLKO/RA6 — Oscillator output / Clock output / PORTA bit 6 |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 module |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / CCP1 module (PWM/Capture/Compare) |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0/C1IN+ — PORTD bit 0 / Parallel Slave Port data / Comparator 1 input |
| Pin 20 | RD1/PSP1/C1IN- — PORTD bit 1 / Parallel Slave Port / Comparator 1 input |
| Pin 21 | RD2/PSP2/C2IN+ — PORTD bit 2 / Parallel Slave Port / Comparator 2 input |
| Pin 22 | RD3/PSP3/C2IN- — PORTD bit 3 / Parallel Slave Port / Comparator 2 input |
| Pin 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 25 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 27 | RD4/PSP4/ECANRX — PORTD bit 4 / Parallel Slave Port / ECAN receive |
| Pin 28 | RD5/PSP5/CANTX — PORTD bit 5 / Parallel Slave Port / CAN transmit |
| Pin 29 | RD6/PSP6/TX2/CK2 — PORTD bit 6 / Parallel Slave Port / USART2 TX / USART2 clock |
| Pin 30 | RD7/PSP7/RX2/DT2 — PORTD bit 7 / Parallel Slave Port / USART2 RX / USART2 data |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply voltage (5V) |
| Pin 33 | RB0/INT0/FLT0 — PORTB bit 0 / External interrupt 0 / PWM fault input |
| Pin 34 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 35 | RB2/INT2/CANTX — PORTB bit 2 / External interrupt 2 / CAN transmit (alternate) |
| Pin 36 | RB3/INT3/CANRX — PORTB bit 3 / External interrupt 3 / CAN receive (alternate) |
| Pin 37 | RB4/KBI0 — PORTB bit 4 / Keyboard interrupt |
| Pin 38 | RB5/KBI1/PGM — PORTB bit 5 / Keyboard interrupt / LVP programming |
| Pin 39 | RB6/KBI2/PGC — PORTB bit 6 / Keyboard interrupt / ICSP clock |
| Pin 40 | RB7/KBI3/PGD — PORTB bit 7 / Keyboard interrupt / ICSP data |
Typical Applications
PIC18F4685-E/P is suitable for 6 applications: Industrial CAN Bus Nodes, Automotive Body Control Modules, Building Automation Gateways, Industrial Sensor Data Loggers, HVAC Controller Boards, CAN-Based Motor Control Nodes.
Industrial CAN Bus Nodes
The PIC18F4685-E/P's integrated Enhanced CAN (ECAN) 2.0B controller and 96KB flash make it a strong fit for industrial CAN nodes running CANopen or DeviceNet stacks. The 96KB program memory accommodates a full CANopen CIA 401/402/301 stack plus application firmware, while ECAN's hardware acceptance filtering and 8 transmit/receive buffers offload message routing from the CPU. The -40C to +125C extended temperature grade supports deployment in unconditioned factory cabinets and outdoor installations. A typical node reads 10-bit ADC channels for sensor data, transmits via ECAN at 250 kbps, and runs the application loop at 40MHz (10 MIPS). Unlike external CAN controllers, the on-chip ECAN reduces BOM cost and PCB area in modular PLC I/O slices.
Recommended
Automotive Body Control Modules
The PIC18F4685-E/P suits automotive body and chassis ECUs (lighting controllers, door modules, HVAC actuators) where ECAN networking and extended temperature are required. With 96KB flash and 3.25KB RAM, the firmware can include a CAN-based diagnostic layer (UDS over CAN) plus actuator control loops. The 36 digital I/O pins drive relays, MOSFET gates, and LED arrays directly, while PWM outputs control motor speed. The -40C to +125C range handles under-hood thermal stress. Compared to 16-bit MCUs, this part offers lower BOM cost while still delivering real-time deterministic performance for body-domain control loops.
Recommended
Building Automation Gateways
The PIC18F4685-E/P bridges building automation protocols (BACnet MS-TP, Modbus RTU) to higher-level networks via CAN or serial links. Its 96KB flash stores full protocol stacks plus gateway routing logic, and the ECAN module can be repurposed for proprietary building-bus communications. The 40-pin PDIP package simplifies installation in DIN-rail gateway enclosures and field-replaceable modules. Multiple serial interfaces (USART, MSSP SPI/I2C) allow concurrent connection to sensor buses and the upstream IP gateway. The extended temperature range ensures reliable operation in mechanical rooms and unheated basements.
Recommended
Industrial Sensor Data Loggers
The PIC18F4685-E/P powers multi-channel sensor data loggers that capture ADC samples, timestamps them, and forward data via CAN, RS-485, or USB. With 96KB flash, the firmware can include file-system drivers for SD card storage and USB mass-storage emulation alongside sampling logic. The 3.25KB RAM buffers ADC scan groups before CAN transmission. The -40C to +125C range supports outdoor deployment for weather stations, environmental monitors, and renewable-energy inverter telemetry. Compared to higher-end ARM Cortex-M0 parts, the PIC18F4685 offers deterministic interrupt latency critical for time-stamped CAN data frames.
Recommended
HVAC Controller Boards
The PIC18F4685-E/P fits HVAC control boards where multiple temperature sensors, fan PWM outputs, and communication interfaces are required. The 36 I/O pins interface with NTC thermistors via 10-bit ADC, drive triac gates for compressor control, and provide PWM outputs for variable-speed fans. The ECAN module can connect to building automation networks for centralized control. With -40C to +125C operating range, the part withstands rooftop unit enclosures in summer. Compared to ARM-based HVAC controllers, this PIC18 solution has a longer lifecycle and lower BOM cost for cost-sensitive consumer HVAC products.
Recommended
CAN-Based Motor Control Nodes
The PIC18F4685-E/P serves as a distributed motor control node receiving speed commands over CAN and driving local BLDC or stepper motors via PWM outputs. Its PWM and capture/compare peripherals generate the switching waveforms, while ECAN handles real-time command reception with sub-millisecond latency. The 96KB flash stores field-oriented control (FOC) or trapezoidal commutation algorithms. The 40-pin PDIP package simplifies development on breadboards and through-hole PCBs for prototyping. Compared to DSP-based motor controllers, this part offers a lower-cost path for low-to-mid power motor nodes in conveyor and pump applications.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4685-E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4685-I/P | PIC18F4682-I/P | PIC18F4585-E/P | PIC18F4680-E/P | PIC18F46K80-I/P |
|---|---|---|---|---|---|---|
| Package | 40-pin PDIP | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same | 40-pin PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Program Memory | 96 KB | 96 KB (same) | 80 KB (-17%) | 48 KB (-50%) | 48 KB (-50%) | 64 KB (-33%) |
| CAN Module | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B | CAN (not Enhanced) | ECAN 2.0B |
| 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 | 1.8 V to 5.5 V |
| Operating Temperature | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +125C (Extended) | -40C to +85C (Industrial) |
| Data RAM | 3.25 KB | 3.25 KB (same) | 3.25 KB (same) | 3.25 KB (same) | 3.25 KB (same) | 3.6 KB (+11%) |
| EEPROM | 1 KB | 1 KB (same) | 1 KB (same) | 1 KB (same) | 1 KB (same) | 1 KB (same) |
| I/O Pins | 36 | 36 (same) | 36 (same) | 36 (same) | 36 (same) | 36 (same) |
| Unit Price (qty 1, as of 2026-09-28) | ~$9.13 | ~$8.20 (slightly cheaper) | ~$7.50 | ~$8.00 | ~$7.20 | ~$5.50 |
Key Differentiators
- Extended -40C to +125C operating temperature range (vs PIC18F4685-I/P)
- Doubled Flash program memory vs PIC18F4585 and PIC18F4680 (vs PIC18F4585-E/P)
- Integrated Enhanced CAN (ECAN) 2.0B controller (vs PIC18F4680-E/P)
Design Notes
Decouple VDD/AVDD with a 100nF ceramic capacitor placed within 5mm of each supply pin; add a 10uF bulk capacitor near the MCU. The PIC18F4685-E/P has multiple VDD/VSS pairs (pins 11/12, 31/32) - bypass each pair individually to prevent digital switching noise from coupling into the analog reference. AVDD/VSS pins should be filtered with a ferrite bead from VDD if analog accuracy is critical (e.g., for ADC measurements below 1 LSB).
ECAN bus signals (CANTX/CANRX, pins 27/28 in default mapping or RB2/RB3 alternate) require careful PCB routing. Per Microchip AN1245, route CANH/CANRX as a differential pair with 100-ohm characteristic impedance, keep stubs under 25mm, and place the MCP2551 transceiver within 50mm of the MCU. Add TVS protection (e.g., NUP2105L) at the bus connector for ESD and transient immunity. ECAN bit timing must be calculated against the chosen baud rate (e.g., 250 kbps or 500 kbps) using the BRP, PRSEG, SEG1PH, and SEG2PH registers per CAN 2.0B specification.
Do not apply voltage above 5.5V to VDD - this part is not 3.3V tolerant on I/O pins when VDD is at 5V. For designs migrating to PIC18F46K80-I/P, the wider 1.8V-5.5V supply range allows 3.3V operation directly. The MCLR pin (pin 1) must have a pull-up to VDD and a 10-100nF cap to ground for proper reset; if left floating, the part may intermittently reset or fail to start. Avoid using the ICSP pins (RB6/RB7) as high-speed outputs during in-circuit programming, as the debugger drives these pins.
Estimated: at 40MHz clock, 5V supply, and full I/O toggling, the PIC18F4685-E/P consumes approximately 50mA (250mW). Through-hole PDIP packages have low thermal resistance (~50 C/W theta_JA), so the junction temperature rise at 25C ambient is only ~12.5C - well within the -40C to +125C operating range. However, in enclosed industrial cabinets at 70C ambient, the junction can reach 82.5C; verify the maximum ambient plus self-heating stays below 125C with a thermal margin of at least 10C.
Compliance Information
RoHS and Pb-free compliant per Microchip product page. PIC18F4685 family is not AEC-Q100 qualified - for AEC-Q100 automotive requirements, consult Microchip automotive-grade PIC18 portfolio (separate part numbers). REACH status compliant per Microchip environmental compliance documentation.
