PIC18F2685-E/SO - 8-bit MCU 96KB Flash ECAN 28-SOIC | Microchip
MPN: PIC18F2685-E/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.9 | $8.90 |
| 10 | $7.95 | $79.50 |
| 100 | $7.1 | $710.00 |
| 500 | $6.45 | $3,225.00 |
| 1,000 | $5.8 | $5,800.00 |
PIC18F2685-E/SO Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, program memory (Flash/ROM), data memory (RAM/EEPROM), and a rich set of programmable peripherals. The PIC18 family is Microchip's 8-bit RISC architecture positioned above PIC16, offering C-friendly Harvard architecture, linear memory model, and interrupt-driven I/O. Within that hierarchy, the PIC18F2685 belongs to the PIC18F2x85 sub-family that adds an integrated ECAN peripheral, making it a frequent choice for automotive body, gateway, and industrial CAN nodes where a separate CAN transceiver IC is the only external companion needed.
Key features include 25 digital I/O pins, 11-channel 10-bit ADC, two analog comparators, two 8-bit timers plus three 16-bit timers, 9 PWM outputs, and a hardware ECAN engine that handles CAN 2.0A/B frame transmission and reception with acceptance filters. The 'E' suffix denotes the extended industrial temperature grade of -40C to +125C; the 'SO' package suffix indicates 28-pin SOIC (300-mil). nanoWatt technology delivers multiple idle/sleep modes with current consumption under 1 uA in sleep, suitable for always-on automotive nodes.
The device is built on an enhanced Harvard RISC core with a hardware multiplier (8x8 single-cycle), 16-bit instructions, and up to 10 MIPS sustained throughput. The integrated ECAN block implements the Bosch CAN 2.0B active specification including extended identifiers, programmable bit rates up to 1 Mbit/s, and 6 hardware acceptance-filter masks, offloading the CPU entirely from bit-stuffing and arbitration tasks.
Typical applications include automotive body-control modules, HVAC and instrument-cluster nodes, LIN master/slave gateways, industrial CANopen sensors and motor controllers, building-automation fieldbus nodes, and any 5V-tolerant embedded system requiring on-chip CAN plus 10-bit analog sensing without an external ADC. When migrating legacy PIC18F2585 firmware, the PIC18F2685 is code-compatible while doubling program memory and adding dedicated ECAN hardware.
When designing with this device, ensure that the ECAN module is configured before the bus is enabled and that the CAN transceiver (e.g. MCP2551) supply ramps in a valid sequence. Use the on-chip 10-bit ADC with an external Vref for ratiometric measurements, and place a 0.1 uF decoupling cap as close to VDD as the SOIC pin pitch allows.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical ECAN/PCB design notes not consolidated in the manufacturer datasheet, going beyond the typical parametric listing.
Drop-in alternatives for PIC18F2685-E/SO — 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 PIC18F2685-E/SO (same form factor and footprint) — differing in Package, Timers, ADC, Mounting Type, EEPROM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F2682-E/SO
✅ Drop-In✓ In Stock
$5.95 / Unit
View Datasheet →PIC18F2682-I/SP
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.31 / Unit
View Datasheet →PIC18F2585-E/SO
✅ Drop-In✓ In Stock
$5.3 / Unit
View Datasheet →PIC18F2585-I/SO
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.35 / Unit
View Datasheet →PIC18F2680-E/SP
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$7.75 / Unit
View Datasheet →PIC18F2685-E/SO Maximum Ratings & Electrical Characteristics
| Product Family | PIC18Fxx8x Enhanced Flash MCU with ECAN |
| Core | 8-bit PIC18 RISC (Harvard, 16-bit instructions) |
| Max CPU Frequency | 40 MHz (10 MIPS) |
| Program Memory (Flash) | 96 KB (48K x 16 words) |
| Data Memory (RAM) | 3328 bytes |
| Data EEPROM | 1024 bytes |
| I/O Pins | 25 |
| ADC | 10-bit, up to 11 channels |
| ECAN Module | CAN 2.0B active, 6 acceptance-filter masks |
| Timers | 2x 8-bit + 3x 16-bit |
| PWM Outputs | 9 |
| Comparators | 2 analog comparators |
| Serial Interfaces | ECAN + USART (LIN) + MSSP (SPI/I2C) |
| Package | 28-pin SOIC (300-mil) |
| Operating Temperature | -40C to +125C (Extended, 'E' suffix) |
| Supply Voltage | 4.2 V to 5.5 V (5V typical) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC18F2685-E/SO Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear (reset) input / digital input-only RE3 |
| 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/TOCKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/RA7 — Crystal oscillator input / PORTA bit 7 |
| Pin 10 | OSC2/RA6 — Crystal oscillator output / PORTA bit 6 |
| Pin 11 | RC0/T1OSO — PORTC bit 0 / Timer1 oscillator output |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply (4.2V to 5.5V) |
| Pin 21 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 22 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 23 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 24 | RB3/INT3 — PORTB bit 3 / external interrupt 3 |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data |
Typical Applications
PIC18F2685-E/SO is suitable for 6 applications: Automotive Body Control Module, Industrial CANopen Sensor Node, LIN Master Gateway, HVAC Control Node, Instrument Cluster Node, Building Automation Fieldbus Node.
Automotive Body Control Module
The PIC18F2685-E/SO fits automotive body-control modules because its integrated ECAN controller implements CAN 2.0B active, eliminating the need for an external SPI-to-CAN bridge and freeing the MCU for body-control logic. The 96 KB Flash supports OSEK/OSEKtime or AUTOSAR-style application code plus a CAN bootloader, while the extended -40C to +125C temperature grade handles under-dash thermal environments. The 11-channel 10-bit ADC reads multiplexed analog switches and the 9 PWM outputs drive LED dimming, mirror adjustment, and small DC loads via MOSFET drivers. Compared with a PIC18F25K22-based design, no external CAN controller IC is needed, cutting BOM cost, PCB area, and firmware complexity.
Recommended
Industrial CANopen Sensor Node
For industrial CANopen sensors, the PIC18F2685-E/SO delivers the integrated ECAN peripheral that maps directly onto the CANopen DS301 communication profile, supporting up to 1 Mbit/s bit rates and 6 hardware acceptance-filter masks for PDO filtering. The 3328 bytes of RAM comfortably hold CANopen object dictionaries for sensor-class devices, and the 1024-byte EEPROM stores non-volatile calibration constants. The 10-bit ADC with 11 channels handles multiple ratiometric sensor inputs (strain gauge, thermistor, potentiometer) when paired with an external Vref. nanoWatt sleep modes reduce average current below 1 uA for battery-powered remote sensor nodes, while the -40C to +125C range survives industrial enclosures.
Recommended
LIN Master Gateway
The PIC18F2685-E/SO works as a LIN master gateway because the USART module supports LIN 1.3/2.0 master mode with automatic break-generation and baud-rate detection, while ECAN connects upstream to a higher-speed CAN backbone. The 96 KB Flash holds both the LIN scheduler and CAN-to-LIN translation stack without external memory, and the 25 I/O pins drive local actuator loads. The extended temperature grade and 5V tolerance make it compatible with legacy 12V automotive wiring and 24V industrial truck buses. Compared with discrete LIN-only slaves, the dual-protocol capability removes a translator MCU from the BOM.
Recommended
HVAC Control Node
In HVAC control nodes the PIC18F2685-E/SO provides 9 PWM outputs sufficient to drive multiple fan speeds, damper servo controls, and LED status indicators while the 11-channel ADC reads mixed temperature, pressure, and humidity sensor inputs. The ECAN interface communicates with the building automation backbone, and the 25 I/O pins handle keypad scanning and 7-segment display multiplexing directly. nanoWatt idle/sleep modes keep idle-room controllers below 1 uA standby current. The extended -40C to +125C range ensures operation in plenum spaces, and the 5V supply is compatible with conventional 24V-AC-transformed HVAC power rails.
Recommended
Instrument Cluster Node
The PIC18F2685-E/SO suits instrument-cluster slave nodes because the hardware ECAN offloads CAN message traffic for gauge and warning-indicator data, leaving the CPU free to drive stepper motors for analog gauges via the PWM timers. The 10-bit ADC with 11 channels reads fuel-level, temperature, and battery-voltage sensors directly, while 96 KB of Flash stores cluster graphics and diagnostic firmware. Compared with PIC18F46K22-based designs lacking ECAN, no external MCP2515 SPI-CAN IC is needed, simplifying PCB layout and reducing interrupt load.
Recommended
Building Automation Fieldbus Node
In building-automation fieldbus nodes, the PIC18F2685-E/SO provides CANopen or DeviceNet compatibility via its integrated ECAN controller, while MSSP (SPI/I2C) connects to local sensor front-ends and the USART handles RS-485 fallback. The 96 KB Flash hosts full CANopen stack libraries, and the 3328 bytes of RAM accommodate PDO/TPDO buffers for sensor data. The 25 I/O lines drive relays and indicator LEDs, while the -40C to +125C temperature range tolerates rooftop mechanical-room environments. nanoWatt sleep modes let battery-backed nodes meet energy-harvesting duty cycles.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F2685-E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F2682-E/SO | PIC18F2585-E/SO | PIC18F2680-E/SP |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-pin SOIC | 28-pin SOIC - same | 28-pin SOIC - same | 28-pin SOIC - same |
| Flash Program Memory | 96 KB | 80 KB | 48 KB | 64 KB |
| RAM | 3328 bytes | 3328 bytes | 3328 bytes | 3328 bytes |
| EEPROM | 1024 bytes | 1024 bytes | 1024 bytes | 1024 bytes |
| ECAN Module | Yes (CAN 2.0B) | Yes (CAN 2.0B) | Yes (CAN 2.0B) | No (SPI bridge required) |
| Max CPU Frequency | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) | 40 MHz (10 MIPS) |
| Operating Temperature | -40C to +125C (Extended) | -40C to +125C (Extended) | -40C to +125C (Extended) | -40C to +125C (Extended) |
| I/O Pins | 25 | 25 | 25 | 25 |
| ADC | 10-bit, 11 channels | 10-bit, 11 channels | 10-bit, 11 channels | 10-bit, 11 channels |
Key Differentiators
- Largest Flash in the 28-pin SOIC PIC18F2x85 family (vs PIC18F2585-E/SO)
- Dedicated hardware ECAN vs external SPI-CAN bridge (vs PIC18F2680-E/SP)
- 5V-tolerant supply with extended industrial temperature (vs PIC18F25K22-I/SO)
Design Notes
Estimated: at 40 MHz active and 5.0 V VDD the PIC18F2685 draws roughly 12-15 mA per the Microchip 39761c DC characteristics, while sleep current with ECAN disabled is below 1 uA. Place a 100 nF decoupling capacitor as close to pin 20 (VDD) and pin 19 (VSS) as the SOIC lead pitch allows, and add a bulk 10 uF tantalum on the same supply rail. For CAN-bus nodes, keep the MCU supply and the MCP2551 VCC star-pointed at a single ferrite bead to isolate bus transients from the analog AVdd rail.
The 28-pin SOIC land pattern requires 0.05-inch (1.27 mm) pitch pads; route the crystal traces (OSC1/OSC2 on pins 9/10) as short, symmetrical traces with a ground guard ring to avoid injecting noise into the ADC. ECAN TX (RC6) and RX (RC7) traces to the MCP2551 should be kept under 25 mm and routed away from PWM outputs to minimize crosstalk. Avoid running ADC analog traces (RA0-RA5) parallel to digital switching traces for more than 10 mm to preserve 10-bit ADC linearity.
Do not enable the ECAN module until the oscillator is stable and the CAN bit-rate configuration matches the bus; misconfigured BRP/PrS bits cause bus-off error storms. Verify that RA3 (Vref+) and RA2 (Vref-) are tied to clean references before ADC conversion - leaving them floating injects crosstalk. Finally, ensure that the ICSP pins RB6/RB7 are not held low at reset, or the device will enter programming mode instead of running the application.
On CAN-bus nodes, terminate the bus with 120-ohm resistors at each end and use twisted-pair wiring per ISO 11898. The MCP2551 CANH/CANL pins should have common-mode chokes on bus-engineering designs to pass automotive transient tests (ISO 7637). Within the MCU firmware, configure the ECAN acceptance filters to mask out irrelevant message IDs to reduce interrupt load and improve real-time determinism.
Compliance Information
RoHS compliant per Microchip product page. Extended (-40C to +125C) temperature grade but NOT formally AEC-Q100 qualified; consult Microchip automotive PIC portfolio for AEC-Q100 grades. Lead-free matte-tin finish.
