PIC18LF4685-I/P - 8-bit 40MHz 96KB Flash MCU w/ECAN | Microchip
MPN: PIC18LF4685-I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $8.06 | $80.60 |
| 100 | $7.16 | $716.00 |
| 500 | $6.45 | $3,225.00 |
| 1,000 | $5.74 | $5,740.00 |
PIC18LF4685-I/P Overview
What is a PIC18F flash MCU? The PIC18F family is Microchip's high-end 8-bit microcontroller line, combining an enhanced RISC architecture with on-chip flash, nanoWatt power-saving modes, and integrated peripherals. PIC18 microcontrollers sit in the hierarchy as follows: 8-bit MCU -> microcontroller -> embedded controller -> semiconductor IC. They are widely deployed where deterministic performance, low power, and easy in-circuit reprogrammability are required.
Key features of the PIC18LF4685 include 75 instructions with 16-bit instruction width, hardware multiplier for 8x8 unsigned multiplication in one cycle, ECAN controller for automotive and industrial networking, and nanoWatt features such as alternate oscillator modes, sleep current in the microamp range, and selective peripheral disable. The 40-pin PDIP package exposes up to 36 I/O pins depending on peripheral configuration, with 13 ADC channels and 2 comparators on-chip.
Typical applications include CAN-based industrial automation nodes, automotive body and chassis modules running on 12 V rails, low-power sensor hubs, and small appliance controllers. The wide operating voltage and broad peripheral set also make it suitable for building automation and HVAC peripherals where robust field communication is required.
When designing with this part, ensure the supply stays within 2.0 V to 3.8 V for the 'LF' process; running above 3.8 V requires the PIC18F4685 (standard 'F' process). Decouple VDD with 100 nF plus bulk capacitance, and configure the ECAN baud-rate and oscillator carefully per the Microchip CAN bit-timing guide. In-circuit serial programming (ICSP) via PGD/PGC is supported through dedicated pins.
This page synthesizes distributor pricing, same-package drop-in alternatives drawn from the Site MPN list, comparison data, and practical design notes not found in the manufacturer datasheet alone, giving engineers a single reference for procurement and design decisions.
Drop-in alternatives for PIC18LF4685-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 PIC18LF4685-I/P (same form factor and footprint) — differing in ADC, Package, Program Memory (Flash), Mounting Type, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF4682-I/P
✅ Drop-In✓ In Stock
$4.41 / Unit
View Datasheet →PIC18F4685-I/P
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC18LF4585-I/PT
✅ Drop-In✓ In Stock
$6.34 / Unit
View Datasheet →PIC18LF4680-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F458-I/P
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →PIC18LF4685-I/P Maximum Ratings & Electrical Characteristics
| Core | PIC18F 8-bit RISC |
| CPU Speed (Max) | 40 MHz |
| Program Memory (Flash) | 96 KB (48K x 16) |
| Data SRAM | 3 KB |
| Data EEPROM | 1 KB |
| Supply Voltage (VDD) | 2.0 V to 3.8 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 40-pin PDIP (P) |
| I/O Pins | Up to 36 |
| ADC | 10-bit, 13 channels |
| CAN | ECAN (1 module) |
| UART/USART | 1 |
| SPI (MSSP) | 1 |
| I2C (MSSP) | 1 |
| Comparators | 2 |
| Timers (8/16-bit) | 2 x 8-bit, 3 x 16-bit |
| CCP/ECCP | Yes |
| nanoWatt Power Management | Yes |
| Mounting Type | Through-Hole (DIP) |
PIC18LF4685-I/P Pin Configuration
| Pin 1 | MCLR/RE3 — Reset input (active low) / digital input only |
| Pin 2 | RA0/AN0 — PORTA bit 0 / ADC input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / ADC input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / ADC input 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / ADC input 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / ADC input 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / CAN RX / ADC input 5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / CAN TX / ADC input 6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / CAN TX enable / ADC input 7 |
| Pin 11 | VDD — Positive supply (2.0V to 3.8V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1/CLKI/RA7 — External clock input / PORTA bit 7 |
| Pin 14 | OSC2/CLKO/RA6 — External clock output / PORTA bit 6 |
| Pin 15 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator / clock in |
| Pin 16 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator / CCP2 |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM |
| Pin 18 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 19 | RD0/PSP0/C1IN+ — PORTD bit 0 / Parallel Slave Port / Comparator 1 in+ |
| Pin 20 | RD1/PSP1/C1IN- — PORTD bit 1 / Parallel Slave Port / Comparator 1 in- |
| Pin 21 | RD2/PSP2/C2IN+ — PORTD bit 2 / Parallel Slave Port / Comparator 2 in+ |
| Pin 22 | RD3/PSP3/C2IN- — PORTD bit 3 / Parallel Slave Port / Comparator 2 in- |
| 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 TX or clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / USART RX or data |
| Pin 27 | RD4/PSP4/ECCP1 — PORTD bit 4 / Parallel Slave Port / Enhanced CCP1 |
| Pin 28 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port |
| Pin 29 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port |
| Pin 30 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply (2.0V to 3.8V) |
| Pin 33 | RB0/INT0/FLT0 — PORTB bit 0 / External interrupt 0 / PWM fault |
| Pin 34 | RB1/INT1 — PORTB bit 1 / External interrupt 1 |
| Pin 35 | RB2/INT2 — PORTB bit 2 / External interrupt 2 |
| Pin 36 | RB3/INT3/CCP2 — PORTB bit 3 / External interrupt 3 / CCP2 |
| Pin 37 | RB4/KBI0 — PORTB bit 4 / Keyboard interrupt 0 |
| Pin 38 | RB5/KBI1/PGM — PORTB bit 5 / Keyboard interrupt 1 / LVP program |
| Pin 39 | RB6/KBI2/PGC — PORTB bit 6 / Keyboard interrupt 2 / ICSP clock |
| Pin 40 | RB7/KBI3/PGD — PORTB bit 7 / Keyboard interrupt 3 / ICSP data |
Typical Applications
PIC18LF4685-I/P is suitable for 6 applications: CAN-Based Industrial Automation Nodes, Automotive Body and Chassis Modules, Low-Power Sensor Hubs, Small Appliance and HVAC Controllers, Building Automation Gateways, Industrial Sensor Signal Conditioning.
CAN-Based Industrial Automation Nodes
The PIC18LF4685-I/P's integrated Enhanced CAN (ECAN) module and 96 KB of flash make it a strong fit for industrial automation endpoints such as remote I/O blocks, motor controllers, and sensor bridges on CANopen or DeviceNet networks. With a 40 MHz CPU delivering 10 MIPS, it can service CAN interrupts while executing periodic control loops. The 2.0 V to 3.8 V supply range lets the MCU share a regulated 3.3 V rail with industrial transceivers like the MCP2562, simplifying power architecture. Compared with discrete CAN controllers, integrating the controller on-die reduces PCB area and BOM cost, while nanoWatt sleep modes drop average current to microamps for energy-harvested or battery-backed sensor nodes.
Recommended
Automotive Body and Chassis Modules
Body controllers, lighting modules, and chassis subsystems that require ECAN networking benefit from the PIC18LF4685-I/P's ECAN peripheral, 13-channel 10-bit ADC, and PWM outputs from CCP/ECCP. Operating from -40C to +85C industrial range, it is suitable for cabin-mounted modules on 12 V vehicle rails fed via a 3.3 V regulator. The 96 KB flash leaves room for CANopen, J1939, or OEM-specific stacks plus diagnostics. For AEC-Q100 qualified requirements in safety-critical modules, however, choose the automotive-grade PIC18F4685-I/P variant instead - the standard industrial version is not AEC-Q100 qualified.
Recommended
Low-Power Sensor Hubs
The PIC18LF4685-I/P's nanoWatt technology, including Sleep mode under 1 uA and selective peripheral disable, suits battery-fed wireless sensor hubs that wake periodically to read sensors and transmit data. Running on a regulated 2.0 V to 3.8 V supply from a Li-ion or 2x AA battery stack, the device can stay in sleep most of the time and burst-process on interrupt. The 10-bit ADC with 13 input channels handles multiple analog sensors in parallel. Pair the MCU with an SPI-based sensor front end and a sub-GHz or BLE radio to build a multi-year battery node.
Recommended
Small Appliance and HVAC Controllers
HVAC peripherals, washing-machine sub-boards, and small white-goods controllers benefit from the PIC18LF4685-I/P's 40 MHz throughput, PWM peripherals for motor control, and ECAN for networked appliances. The 40-pin through-hole PDIP simplifies hand prototyping and rework on legacy 8-bit designs. The 1 KB of internal EEPROM supports persistent storage of configuration, calibration, and fault logs across power cycles. Combined with the on-chip comparators and timers, the device can implement closed-loop fan, pump, or valve control without external analog circuitry.
Recommended
Building Automation Gateways
Building automation gateways that bridge ECAN to BACnet, Modbus, or proprietary fieldbuses can rely on the PIC18LF4685-I/P for protocol translation, local I/O aggregation, and store-and-forward buffering. The 96 KB flash fits BACnet/Modbus stacks plus a small web or serial configuration interface. The ECAN controller handles multiple building-automation messages per millisecond while USART/SPI provide additional fieldbus channels. Industrial temperature rating and the 40-pin PDIP simplify integration into legacy control cabinets where through-hole parts are still preferred.
Recommended
Industrial Sensor Signal Conditioning
The PIC18LF4685-I/P's 13-channel 10-bit ADC, dual comparators, and PWM outputs make it well suited to industrial signal-conditioning front ends that must digitize strain-gauge, thermocouple, or process-current (4-20 mA) signals and provide a CAN output. The integrated ECAN module pushes digitized sensor values onto a CAN network for PLC consumption, while the on-chip comparators implement window-detection for over-range/under-range alarms. nanoWatt modes reduce idle power in field-mounted instrumentation that runs on loop power or small batteries.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4685-I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF4682-I/P | PIC18F4685-I/P | PIC18LF4585-I/P | PIC18LF4680-I/P | PIC18F458-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 |
| Program Memory (Flash) | 96 KB | 80 KB | 96 KB | 48 KB | 64 KB | 32 KB |
| Data SRAM | 3 KB | 3 KB | 3 KB | 3 KB | 3 KB | 1.5 KB |
| Data EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB | 256 B |
| CPU Speed (Max) | 40 MHz / 10 MIPS | 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 3.8 V (LF) | 2.0 V to 3.8 V (LF) | 4.2 V to 5.5 V (F) | 2.0 V to 3.8 V (LF) | 2.0 V to 3.8 V (LF) | 4.2 V to 5.5 V (F) |
| CAN Module | ECAN | ECAN | ECAN | Legacy CAN (not ECAN) | None (no CAN) | None (no CAN) |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Lowest-cost ECAN + 96 KB flash in 40-pin PDIP on the Microchip PIC18F portfolio (vs PIC18LF4682-I/P)
- Low-voltage LF process supports 2.0-3.8 V rails for battery-powered designs (vs PIC18F4685-I/P)
- Enhanced CAN with hardware filtering for high-throughput industrial networks (vs PIC18LF4585-I/P)
- On-chip 1 KB EEPROM for persistent data with no external memory (vs PIC18F458-I/P)
Design Notes
The PIC18LF4685-I/P is a 2.0 V to 3.8 V 'LF' part; applying 5 V will damage it. Always pair with a low-dropout regulator such as the MCP1700-3302E (3.3V, 250 mA, 1.6 uA Iq) for 3.3 V system rails, or directly drive from 2x AA batteries for portable designs. Place 100 nF + 10 uF bulk + 10 uF bulk on each VDD pin and a single VSS star ground near the MCU. Verify VDD stays above the brown-out voltage threshold configured via BOREN/CONFIG for reliable startup in noisy industrial environments.
Do not confuse the 'LF' (low-voltage) part with the 'F' (4.2-5.5 V) PIC18F4685; they are NOT drop-in replacements for each other when VDD is 5 V. For 5 V rails, use PIC18F4685-I/P instead. ECAN requires a separate external transceiver - the on-chip ECAN module only handles digital protocol. Configure CAN bit timing per Microchip AN228 (CiA 102/DS301) or your specific higher-layer protocol. Always define unused I/O as outputs (low) to minimize current draw in sleep mode.
Keep the high-speed ECAN traces (RE0/RE1/RE2) short and matched within a few mm of each other; add 100 ohm +/- 1% termination resistors at the bus ends. Place the CAN transceiver (MCP2562) physically between the MCU and the bus connector. For ICSP, route PGC/PGD as short, parallel traces with no stubs; add a 4.7 kohm pull-up on MCLR to VDD if not already present, and a small 100 nF cap on VDD close to pin 11 to reduce programming noise.
The 40-pin PDIP package has good thermal dissipation for typical 8-bit MCU loads (typically <100 mW). At 40 MHz full activity with all peripherals enabled, expect roughly 25-30 mA core current at 3.3 V; verify that the LDO and traces can supply this with adequate margin. Estimated: VDD = 3.3 V x IDD = 30 mA = 99 mW - well within the PDIP's ~800 mW rating at room temperature. In a sealed enclosure, verify junction temperature stays below 85C using the package theta_JA from the datasheet.
Compliance Information
RoHS / REACH / lead-free status not explicitly stated in the verified distributor data and is marked as unknown - confirm with Microchip lot documentation. The standard industrial 'I' variant is not AEC-Q100 qualified; AEC-Q100 work requires automotive-grade Microchip PIC18F4685-I/P variants with specific part numbers. For critical automotive deployments, request the official material declaration from Microchip support.
