PIC18LF4685-I/ML - 8-bit 40MHz MCU 96KB Flash ECAN 44-QFN | Microchip
MPN: PIC18LF4685-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.8 | $8.80 |
| 10 | $7.92 | $79.20 |
| 100 | $7.04 | $704.00 |
| 500 | $6.34 | $3,170.00 |
| 1,000 | $5.63 | $5,630.00 |
PIC18LF4685-I/ML Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program and data memory, peripherals, and I/O. The 8-bit PIC® family sits in the low-power, deterministic-control segment of the MCU market, between 4-bit legacy controllers and 16/32-bit Cortex-M devices, and is widely used for cost-sensitive embedded control, sensor interfacing, and automotive/industrial communication via CAN. The PIC18LF4685 specifically targets low-voltage (LF = 2.0–3.3 V) designs that require CAN connectivity.
Key features include 10 MIPS throughput, hardware ECAN 2.0B, 10-bit ADC up to 100 ksps with up to 11 channels, nanoWatt Technology with multiple idle/sleep modes, an 8 x 8 hardware multiplier, and an ICD (In-Circuit Debug) interface. The wide operating voltage of 2.0–3.3 V and extended industrial temperature range (-40 °C to +85 °C) make the part suitable for battery-powered and automotive-grade designs.
The architecture is a Harvard-modified RISC core with separate program and data buses, 31-level hardware stack, and 75+ instructions including hardware multiply. The ECAN module supports both standard and extended identifiers with acceptance filters, while the 10-bit ADC uses an internal sample-and-hold and can be auto-triggered from timers or PWM edges, reducing CPU overhead in motor-control and sensor-conditioning loops.
Typical applications include automotive ECAN nodes (body control, instrument clusters, sensor interfacing), industrial CAN-based distributed control, low-power sensor hubs, and consumer appliances requiring CAN connectivity. The combination of Flash self-programmability and robust peripherals makes it suitable for designs that must be field-upgradable over the CAN bus.
When designing with this device, ensure that the CAN bus termination, transceiver (e.g. MCP2551), and stub length are matched to the chosen bit rate (up to 1 Mbps). For low-power operation, use nanoWatt sleep modes and verify ADC sampling times against the chosen analog source impedance to avoid linearity errors.
This page synthesizes distributor pricing, same-brand drop-in alternatives (notably PIC18LF4585-I/ML in the same 44-QFN footprint), and practical CAN/ECAN design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC18LF4685-I/ML — 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/ML (same form factor and footprint) — differing in Package, Timers, Operating Temperature, Program Memory (Flash), I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LF4682-I/ML
✅ Drop-In✓ In Stock
$4.4 / Unit
View Datasheet →PIC18LF4585-I/ML
✅ Drop-In✓ In Stock
$5.42 / Unit
View Datasheet →PIC18F4685-I/ML
✅ Drop-In✓ In Stock
$6.48 / Unit
View Datasheet →PIC18LF4580-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF4480-I/ML
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC18LF4685-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit RISC, Harvard) |
| Program Memory (Flash) | 96 KB (48K x 16) |
| Data Memory (SRAM) | 3 KB |
| EEPROM | 1 KB (1024 bytes) |
| Maximum CPU Speed | 40 MHz (10 MIPS) |
| Operating Voltage | 2.0 V to 3.3 V (LF variant) |
| I/O Pins | 36 (approx.) |
| ADC | 10-bit, up to 11 channels |
| CAN Module | ECAN 2.0B active (with filters) |
| PWM Outputs | Yes, ECCP + CCP |
| Timers | Timer0/1/2/3 + WDT |
| Communication | ECAN, UART, SPI, I2C |
| Package | 44-pin QFN (8 mm x 8 mm) with EP |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Debug Interface | ICD / ICSP |
PIC18LF4685-I/ML Pin Configuration
| Pin 1 | RB7/KBI3/PGD — PORTB bit 7 / KBI input / ICSP data |
| Pin 2 | RB6/KBI2/PGC — PORTB bit 6 / KBI input / ICSP clock |
| Pin 3 | RB5/KBI1 — PORTB bit 5 / KBI input |
| Pin 4 | RB4/KBI0 — PORTB bit 4 / KBI input |
| Pin 5 | RB3/CCP2 — PORTB bit 3 / CCP2 PWM/capture |
| Pin 6 | RB2/CANTX — PORTB bit 2 / ECAN TX output |
| Pin 7 | RB1/CANRX — PORTB bit 1 / ECAN RX input |
| Pin 8 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 9 | VDD — Digital supply (2.0–3.3 V) |
| Pin 10 | VSS — Digital ground |
| Pin 11 | RC7/RX/DT — PORTC bit 7 / EUSART RX |
| Pin 12 | RC6/TX/CK — PORTC bit 6 / EUSART TX |
| Pin 13 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC3/SCL — PORTC bit 3 / I2C clock |
| Pin 16 | RC2/CCP1/P1A — PORTC bit 2 / CCP1 PWM |
| Pin 17 | RC1/CCP2 — PORTC bit 1 / CCP2 (alt) |
| Pin 18 | RC0/T1CKI — PORTC bit 0 / Timer1 clock input |
| Pin 19 | OSC1/CLKI — Oscillator input / external clock in |
| Pin 20 | OSC2/CLKO — Oscillator output |
| Pin 21 | RA0/AN0 — PORTA bit 0 / ADC input 0 |
| Pin 22 | RA1/AN1 — PORTA bit 1 / ADC input 1 |
| Pin 23 | RA2/AN2/VREF- — PORTA bit 2 / ADC input 2 / VREF- |
| Pin 24 | RA3/AN3/VREF+ — PORTA bit 3 / ADC input 3 / VREF+ |
| Pin 25 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 26 | RA5/AN4 — PORTA bit 5 / ADC input 4 |
| Pin 27 | AVDD — Analog supply (2.0–3.3 V) |
| Pin 28 | AVSS — Analog ground |
| Pin 29 | RD7/PSP7 — PORTD bit 7 / parallel slave port |
| Pin 30 | RD6/PSP6 — PORTD bit 6 |
| Pin 31 | RD5/PSP5 — PORTD bit 5 |
| Pin 32 | RD4/PSP4 — PORTD bit 4 |
| Pin 33 | RD3/PSP3 — PORTD bit 3 |
| Pin 34 | RD2/PSP2 — PORTD bit 2 |
| Pin 35 | RD1/PSP1 — PORTD bit 1 |
| Pin 36 | RD0/PSP0 — PORTD bit 0 |
| Pin 37 | RE3/MCLR/VPP — PORTE bit 3 / reset (active low) / VPP |
| Pin 38 | RE2/CS — PORTE bit 2 |
| Pin 39 | RE1/WR — PORTE bit 1 |
| Pin 40 | RE0/RD — PORTE bit 0 |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | EP — Exposed thermal pad — connect to ground |
Typical Applications
PIC18LF4685-I/ML is suitable for 6 applications: Automotive ECAN Body Control Module, Industrial Sensor / Distributed Control Node, Battery-Powered Sensor Hub with CAN Wake, Instrument Cluster and Dashboard Display, Smart Agriculture / CAN-Connected Sensor Node, Building Automation and HVAC CAN Gateway.
Automotive ECAN Body Control Module
The PIC18LF4685-I/ML fits automotive body-control ECAN nodes due to its integrated ECAN 2.0B controller, 96 KB Flash for bootloader and J1939 or CANopen stack, and 2.0–3.3 V operation compatible with 3.3 V-only BCM rails. The 10-bit ADC with up to 11 channels digitizes body sensors (temperature, light, position) while the ECAN DMA-style mailboxes offload message buffering from the CPU. Placed on the BCM main PCB, it pairs naturally with an MCP2562 CAN transceiver for the physical bus and operates across -40 °C to +85 °C industrial temperature range.
Recommended
Industrial Sensor / Distributed Control Node
The PIC18LF4685-I/ML is well-suited for industrial distributed-control nodes because ECAN 2.0B with acceptance filters allows multi-drop networking on long cable runs, while 96 KB Flash and 3 KB RAM host Modbus-to-CAN gateway logic. The 10 MIPS throughput and hardware 8x8 multiplier handle sensor linearization and PID control loops in real time. Power is drawn from 24 V industrial rails stepped down to 3.3 V, and the 44-QFN package's small footprint enables DIN-rail mountable node designs.
Recommended
Battery-Powered Sensor Hub with CAN Wake
The PIC18LF4685-I/ML supports battery-powered sensor hubs thanks to nanoWatt Technology sleep modes that drop quiescent current below typical consumption. The 2.0–3.3 V LF operation suits 2xAA / Li-Ion battery chemistries directly, and ECAN wake-on-message capability lets the hub stay asleep until a valid CAN frame arrives. The 96 KB Flash hosts sensor fusion and over-the-air firmware updates via CAN bootloader, extending product service life in the field.
Recommended
Instrument Cluster and Dashboard Display
The PIC18LF4685-I/ML drives instrument-cluster ECAN slaves because its ECAN 2.0B controller can decode up to 16 acceptance filter entries, isolating cluster-relevant frames from bus traffic. The 36 I/O pins drive segment LCDs, stepper motors for gauges, and indicator LEDs without external expanders. With 10 MIPS throughput, the MCU simultaneously refreshes the display, reads the ADC inputs (fuel, temperature), and services CAN messages without timing overruns.
Recommended
Smart Agriculture / CAN-Connected Sensor Node
The PIC18LF4685-I/ML supports agricultural sensor nodes that need robust CAN communication over long cable runs in noisy EMI environments. ECAN's hardware acceptance filters isolate local sensors from the broader field bus, while the 10-bit ADC reads soil moisture, temperature, and NPK sensors with up to 11 channels. The 44-QFN package's small footprint (8x8 mm) fits inside weatherproof sensor housings, and nanoWatt Technology maximizes battery life between field-service visits.
Recommended
Building Automation and HVAC CAN Gateway
The PIC18LF4685-I/ML is well-suited to building-automation gateways that bridge BACnet, Modbus, or proprietary HVAC protocols over CAN. The 96 KB Flash accommodates BACnet MS/TP plus a CANopen gateway stack, while 3 KB RAM buffers message traffic between the two buses. Multiple UART, SPI, and I2C peripherals connect to environmental sensors and the ECAN module exposes the gateway on the building CAN trunk. The 2.0–3.3 V operation lets the gateway share a 3.3 V rail with sensors.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LF4685-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LF4682-I/ML | PIC18LF4585-I/ML | PIC18F4685-I/ML | PIC18LF4580-I/ML | PIC18LF4480-I/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-QFN (8x8) | 44-QFN (8x8) - same | 44-QFN (8x8) - same | 44-QFN (8x8) - same | 44-QFN (8x8) - same | 44-QFN (8x8) - same |
| Flash Memory | 96 KB | 79 KB | 48 KB | 96 KB | 32 KB | 16 KB |
| SRAM | 3 KB | 1.2 KB | 3 KB | 3 KB | 1.5 KB | 1.2 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 256 B | 256 B |
| CPU Speed | 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 | 2.0–3.3 V | 2.0–3.3 V | 2.0–3.3 V | 4.2–5.5 V | 2.0–3.3 V | 2.0–3.3 V |
| CAN Module | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B | ECAN 2.0B |
| ADC | 10-bit, 11 ch | 10-bit, 11 ch | 10-bit, 11 ch | 10-bit, 11 ch | 10-bit, 8 ch | 10-bit, 8 ch |
Key Differentiators
- Highest Flash density in the PIC18F4685 family (vs PIC18LF4585-I/ML)
- 3.3 V low-voltage operation with full ECAN (vs PIC18F4685-I/ML)
- Same 44-QFN package across F/LF/45K/46K families (vs PIC18LF4682-I/ML)
Design Notes
The PIC18LF4685-I/ML is an LF (low-voltage) part rated 2.0–3.3 V; applying 5 V on VDD damages the device. Use an MCP1700 3.3 V LDO from a 5 V upstream rail, and place the LDO within 25 mm of the VDD pins with 1 µF + 100 nF decoupling. For deep power savings use nanoWatt sleep modes (e.g., Sleep/Idle) and ensure all I/O lines are defined (input or output) before sleep to avoid floating-pin current spikes.
The 44-QFN package has an exposed thermal pad (EP) on pin 44 that MUST be soldered to a ground copper pour of at least 25 mm² (5x5 mm) for thermal and electrical performance. Place the ECAN lines (CANTX/CANRX) symmetrically and as short as possible to the MCP2551/MCP2562 transceiver, with 120 Ω termination at each bus end. Route OSC1/OSC2 traces away from switching signals to avoid coupling into the 40 MHz clock.
ECAN bit rates up to 1 Mbps require careful bus impedance: 120 Ω twisted-pair with stub length under 0.3 m at 1 Mbps, 1 m at 500 kbps. The MCP2551/MCP2562 transceiver handles bus faults and ESD; on the MCU side, ensure CANTX has a 10 kΩ pull-up if the transceiver lacks internal one, and CANRX has no pull-up conflict. Acceptance filters in ECAN reduce bus-load CPU overhead — configure them in firmware to drop irrelevant frames before they reach the application buffers.
Common PIC18LF4685-I/ML pitfalls: (1) confusing LF (3.3 V) with F (5 V) variants — the LF part is permanently damaged above 3.6 V on VDD; (2) omitting MCLR pull-up on RE3/MCLR/VPP — without 10 kΩ to VDD the part will randomly reset; (3) using ADC channels above VREF+ — saturates the conversion and corrupts the lower channels if auto-scanning; (4) forgetting to disable ICD pins (PGD/KIT4, PGC/KIT3) when not debugging, which can cause contention on shared lines; (5) exceeding 40 MHz oscillator — internal FOSC divider or external crystal selection must be respected per datasheet section 2.
Compliance Information
RoHS and REACH compliant per Microchip product page; not AEC-Q100 qualified (industrial grade -40 °C to +85 °C). The PIC18F4685-I/ML and AEC-Q100 automotive variants exist for safety-critical automotive applications.
