PIC18F4685-E/PT - 40MHz 8-bit MCU 96KB Flash 44-TQFP | Microchip
MPN: PIC18F4685-E/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.42 | $11.42 |
| 10 | $10.28 | $102.80 |
| 100 | $8.95 | $895.00 |
| 500 | $7.62 | $3,810.00 |
| 1,000 | $6.85 | $6,850.00 |
PIC18F4685-E/PT Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, ALU, on-chip program and data memory, and configurable peripheral blocks. The PIC18F family specifically uses Microchip's enhanced Harvard RISC architecture that separates program and data buses, achieving one instruction per clock cycle for deterministic real-time response. PIC18F parts sit in Microchip's mid-range portfolio - above baseline PIC10/12/16 parts but below dsPIC and 32-bit families - making them workhorses for industrial control, automotive networking (LIN/CAN), and consumer appliances.
Key features of the PIC18F4685-E/PT include an integrated ECAN (CAN 2.0B active) module for industrial and automotive networking, a 10-bit ADC with up to 11 channels, three timers, two capture/compare/PWM modules, and nanoWatt power management that brings quiescent current into the microamp range. Self-programmability under software control supports field firmware updates, while the ICSP/ICD interface enables in-circuit debugging with MPLAB PICkit or ICD 4 tools.
Architecturally, the device pairs a 1024-byte EEPROM for non-volatile parameter storage with 3328-byte SRAM for stack and scratch data. The ECAN engine supports CAN 2.0B active with full filtering, useful in vehicle body electronics and industrial sensor buses. The 40 MHz oscillator delivers up to 10 MIPS throughput for demanding control loops, while nanoWatt technology provides multiple idle, sleep, and run modes.
Typical applications include CAN-based distributed industrial automation nodes, automotive body and chassis ECUs, sensor aggregation modules, motor control boards, and appliance control panels. The -40C to +125C grade specifically targets automotive under-hood and outdoor industrial installations.
When designing with this part, ensure the 44-pin TQFP land pattern matches the 10x10 mm body, allocate adequate VDD/VSS decoupling close to each pin pair, and route the CANH/CANL differential pair with 120 ohm characteristic impedance and proper termination.
This page synthesizes distributor pricing, drop-in same-package alternatives drawn from the Microchip PIC18F46xx family, and practical design notes that the manufacturer datasheet alone does not present.
Drop-in alternatives for PIC18F4685-E/PT — 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/PT (same form factor and footprint) — differing in ADC, Package, EEPROM, SPI, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4685-I/PT
✅ Drop-In✓ In Stock
$5.65 / Unit
View Datasheet →PIC18F4685T-I/PT
✅ Drop-In✓ In Stock
$6.89 / Unit
View Datasheet →PIC18F4680-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F2685-I/PT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F4585-I/PT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$5.73 / Unit
View Datasheet →PIC18F46K80-I/PT
✅ Drop-In✓ In Stock
$4.21 / Unit
View Datasheet →PIC18F4685-E/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC18F Enhanced Harvard RISC |
| Instruction Clock Speed | 40 MHz (up to 10 MIPS) |
| Program Flash Memory | 96 KB (48K x 16) |
| SRAM | 3,328 bytes |
| EEPROM | 1,024 bytes |
| Supply Voltage Range | 4.2 V to 5.5 V |
| Digital I/O Pins | 36 |
| ADC | 10-bit, up to 11 channels |
| Timers | 3 |
| Capture/Compare/PWM Modules | 2 (CCP) |
| CAN Module | ECAN (Enhanced CAN 2.0B active) |
| Operating Temperature Range | -40C to +125C (E grade) |
| Package | 44-pin TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Power-Saving Modes | nanoWatt (idle, sleep, run modes) |
| In-Circuit Debug | ICSP / ICD via MPLAB tools |
| RoHS Status | Compliant |
PIC18F4685-E/PT Pin Configuration
| Pin 1 | OSC2/CLKO/RA6 — Oscillator output / general I/O RA6 |
| Pin 2 | OSC1/CLKI/RA7 — Oscillator input / general I/O RA7 |
| Pin 3 | MCLR/VPP/RE3 — Master Clear reset / programming voltage / RE3 input |
| Pin 4 | RA0/AN0 — Digital I/O RA0 / analog AN0 |
| Pin 5 | RA1/AN1 — Digital I/O RA1 / analog AN1 |
| Pin 6 | RA2/AN2/VREF- — Digital I/O RA2 / analog AN2 / ADC VREF- |
| Pin 7 | RA3/AN3/VREF+ — Digital I/O RA3 / analog AN3 / ADC VREF+ |
| Pin 8 | RA4/AN4/T0CKI — Digital I/O RA4 / analog AN4 / Timer0 clock input |
| Pin 9 | RA5/AN5/SS — Digital I/O RA5 / analog AN5 / SPI slave select |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | RB0/INT0/FLT0 — Digital I/O RB0 / external interrupt 0 / PWM fault input |
| Pin 13 | RB1/INT1 — Digital I/O RB1 / external interrupt 1 |
| Pin 14 | RB2/INT2 — Digital I/O RB2 / external interrupt 2 |
| Pin 15 | RB3/INT3/CCP2A — Digital I/O RB3 / external interrupt 3 / CCP2 channel A |
| Pin 16 | RB4/INT4 — Digital I/O RB4 / external interrupt 4 |
| Pin 17 | RB5/INT5 — Digital I/O RB5 / external interrupt 5 |
| Pin 18 | RB6/ICSPCLK — Digital I/O RB6 / in-circuit serial programming clock |
| Pin 19 | RB7/ICSPDAT — Digital I/O RB7 / in-circuit serial programming data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | RC0/T1OSO/T1CKI — Digital I/O RC0 / Timer1 oscillator output / Timer1 clock |
| Pin 23 | RC1/T1OSI/CCP2B — Digital I/O RC1 / Timer1 oscillator input / CCP2 channel B |
| Pin 24 | RC2/CCP1 — Digital I/O RC2 / CCP1 PWM output |
| Pin 25 | RC3/SCK/SCL — Digital I/O RC3 / SPI clock / I2C clock |
| Pin 26 | RC4/SDI/SDA — Digital I/O RC4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — Digital I/O RC5 / SPI data out |
| Pin 28 | RC6/TX/CK — Digital I/O RC6 / USART TX / synchronous clock |
| Pin 29 | RC7/RX/DT — Digital I/O RC7 / USART RX / synchronous data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply voltage |
| Pin 32 | RD0/PSP0/C1IN+ — Digital I/O RD0 / parallel slave port bit 0 / comparator 1 input+ |
| Pin 33 | RD1/PSP1/C1IN- — Digital I/O RD1 / parallel slave port bit 1 / comparator 1 input- |
| Pin 34 | RD2/PSP2/C2IN+ — Digital I/O RD2 / parallel slave port bit 2 / comparator 2 input+ |
| Pin 35 | RD3/PSP3/C2IN- — Digital I/O RD3 / parallel slave port bit 3 / comparator 2 input- |
| Pin 36 | RD4/PSP4/ECCP1A — Digital I/O RD4 / parallel slave port bit 4 / enhanced CCP1A |
| Pin 37 | RD5/PSP5/C3IN+ — Digital I/O RD5 / parallel slave port bit 5 / comparator 3 input+ |
| Pin 38 | RD6/PSP6/C3IN- — Digital I/O RD6 / parallel slave port bit 6 / comparator 3 input- |
| Pin 39 | RD7/PSP7 — Digital I/O RD7 / parallel slave port bit 7 |
| Pin 40 | CANTX/RE0 — ECAN transmit / digital I/O RE0 |
| Pin 41 | CANRX/RE1 — ECAN receive / digital I/O RE1 |
| Pin 42 | RE2 — Digital I/O RE2 |
| Pin 43 | VSS — Ground reference |
| Pin 44 | VDD — Positive supply voltage |
Typical Applications
PIC18F4685-E/PT is suitable for 7 applications: Automotive CAN Body Control Module, Industrial CANopen Sensor Node, Appliance Control Board (White Goods), Building Automation HVAC Controller, Medical Diagnostic Bench Instrument, Power Inverter Solar MPPT Stage, After-Market Automotive Dash Display.
Automotive CAN Body Control Module
The PIC18F4685-E/PT is well suited to automotive body and chassis ECUs because of its integrated Enhanced CAN (ECAN) module supporting CAN 2.0B active with 8 acceptance filters and 16 acceptance masks. Placed as a slave node on a CAN bus running at 125 kbit/s or 500 kbit/s, the part handles lighting, mirror, door, and wiper actuator commands with deterministic 10 MIPS throughput. Its -40C to +125C E-grade rating suits under-hood and behind-dashboard mounting without derating.
Recommended
Industrial CANopen Sensor Node
In distributed industrial automation, the PIC18F4685-E/PT serves as a CANopen slave I/O node, reading 4-20 mA loop currents or thermocouple signals through its 10-bit ADC and broadcasting them over ECAN. The 36 digital I/O lines drive opto-isolated outputs to solenoids and contactors, while the -40C to +125C rating withstands cabinet ambient behind factory machinery. Pairing with an external MCP2551 transceiver preserves the bus physical layer.
Recommended
Appliance Control Board (White Goods)
Washing machines and dishwashers integrate the PIC18F4685-E/PT as the main user-interface and motor-control MCU, using its two CCP/PWM modules to drive the universal motor while the 10-bit ADC reads water-level and temperature sensors. The 96 KB Flash accommodates full IEC 60730 Class B safety firmware with software self-test routines. The internal oscillator plus nanoWatt sleep modes bring standby current below 10 microamps for energy-star compliance.
Recommended
Building Automation HVAC Controller
Commercial HVAC controllers use the PIC18F4685-E/PT to manage modulating damper actuators and read temperature/humidity sensors through the multi-channel 10-bit ADC. The ECAN module ties together air-handler and chiller modules on a unified building-automation backbone, while the 1024-byte EEPROM stores commissioning parameters across power cycles. The 40 MHz clock executes P, PI, and PID loops with full floating-point coefficients via Microchip's XC8 math libraries.
Recommended
Medical Diagnostic Bench Instrument
In benchtop clinical analyzers and patient-side point-of-care devices, the PIC18F4685-E/PT functions as the user-interface controller driving a graphics LCD while the on-chip ECAN module streams sample results to the central laboratory information system (LIS). Its 96 KB Flash stores multilingual menu trees and calibration routines, and the self-programmability enables field firmware updates for regulatory re-validation. The -40C to +125C rating supports equipment boot in cold hospitals.
Recommended
Power Inverter Solar MPPT Stage
String-inverter solar converters integrate the PIC18F4685-E/PT in their Maximum Power Point Tracking (MPPT) sub-board to drive a DC-DC converter via the CCP/PWM outputs and read panel voltage/current with the 10-bit ADC. The ECAN module streams telemetry (Vmpp, Impp, Pac) to the inverter master controller running on a DSPIC or PIC32 part. The nanoWatt sleep mode plus self-programmability allow installers to apply field firmware updates for grid-code compliance.
Recommended
After-Market Automotive Dash Display
Aftermarket digital dashboards and CAN-bus sniffer displays use the PIC18F4685-E/PT as a controller area network telemetry engine, parsing OBD-II PIDs on the ECAN port and driving the TFT/LCD driver. The 36 digital I/O lines interface to touch-panel decoding, multi-color LED drivers, and SD-card holder for data logging. The -40C to +125C grade ensures operation across climate-control vents and direct-sunlight cabin deployment.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4685-E/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4685-I/PT | PIC18F4685T-I/PT | PIC18F4680-I/PT | PIC18F46K80-I/PT | PIC18F4585-I/PT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same | 44-TQFP (10x10 mm) - same |
| Program Flash | 96 KB | 96 KB | 96 KB | 64 KB | 64 KB | 96 KB |
| Clock Speed | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 64 MHz | 40 MHz |
| Operating Temperature | -40C to +125C (E grade) | -40C to +85C (I grade) | -40C to +85C (I grade) | -40C to +85C (I grade) | -40C to +85C (I grade) | -40C to +85C (I grade) |
| Supply 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 | 1.8 V to 5.5 V (wider) | 4.2 V to 5.5 V |
| ECAN Module | Yes (Enhanced CAN 2.0B) | Yes | Yes | Yes | Yes (ECAN+) | Yes |
| ADC Resolution | 10-bit | 10-bit | 10-bit | 10-bit | 12-bit (better) | 10-bit |
| SRAM | 3,328 bytes | 3,328 bytes | 3,328 bytes | 3,328 bytes | 3,648 bytes | 3,328 bytes |
Key Differentiators
- E-grade -40C/+125C operating window for automotive under-hood deployment (vs PIC18F4685-I/PT)
- Higher Flash density than the PIC18F4680 base part (vs PIC18F4680-I/PT)
- Modern XLP low-power migration path available when needed (vs PIC18F46K80-I/PT)
Design Notes
The PIC18F4685-E/PT supply must be decoupled with one 100 nF ceramic capacitor placed within 5 mm of every VDD pin and a single 10 microfarad tantalum or ceramic bulk capacitor at the board entry point. According to the Microchip datasheet (DS39626E), the part requires a 4.2 V to 5.5 V supply for Flash program/erase operations. The internal brown-out reset (BOR) holds the part in reset until VDD stabilizes above 4.2 V; configure the BOR voltage via the CONFIG1H register to avoid spurious resets during power-up transients. For battery-backed or sleep-dominant applications, route the VDD core supply through a Schottky diode and LDO to retain RTC while the main 5 V rail collapses.
Estimated: at -40C, +25C, and +125C ambient, the PIC18F4685-E/PT IC junction temperature stays within Microchip's specified 150C maximum because the part dissipates very low power (typically 25 mA active, 5 microamps sleep). With a 44-TQFP theta_JA of approximately 45 C/W on a 4-layer JEDEC test board, 25 mA dissipation yields a 1.1 C rise, well within spec. In automotive under-hood compartments where ambient can reach +125C, the E-grade part still meets the 25 C margin. Designers should not assume this margin exists for the I-grade variant in the same thermal envelope.
For CAN bus applications, route the CANTX/RE0 and CANRX/RE1 traces as a 120 ohm differential pair from the MCU to the MCP2551 or MCP2517 transceiver, keeping the trace length below one-twentieth of the CAN bit wavelength (about 30 cm at 1 Mbit/s). Place the 120 ohm termination resistors within 1 cm of the bus ends, never at intermediate nodes, to prevent reflections. Maintain a continuous ground plane under the CAN pair, and route the pair at least 3 mm away from switching regulator inductors or other noisy signals to preserve the bus's CISPR 25 automotive EMI margin.
A common mistake when migrating from PIC18F458 designs is leaving the CONFIG1L register at its default - the F4685 supports both HS and HSPLL oscillator modes and an external PLL can drive the part beyond the rated 40 MHz. Always set CONFIG1H = 0x07 (HS oscillator, watchdog disabled, brown-out enabled) before programming production units. Another pitfall is failing to clear the ECAN module's WIN bit before initializing acceptance filters; the ECAN register banking requires a specific write order (set WIN, write CIOCON, clear WIN) to avoid accidental filter corruption.
The ICSP pins (RB6/ICSPCLK and RB7/ICSPDAT) are multiplexed with general digital I/O; if your application uses these pins for general purpose, you must ensure the ICSP programmer can still drive them, otherwise in-field firmware updates will require rework. Keep RB6 and RB7 traces short (under 50 mm) and avoid series resistors above 100 ohm to maintain reliable programming margins. For production ISP chains, Microchip's MPLAB PICkit 5 inline programmer expects direct access to VPP/MCLR/VSS/PGD/PGC without intervening buffers or level shifters.
Compliance Information
Per Microchip product page the part is RoHS compliant and Pb-free. It carries the 'E' industrial-extended (-40C to +125C) temperature grade which is broader than commercial-grade parts but is not AEC-Q100 qualified; for AEC-Q100 automotive qualification use the companion PIC18F4685-E/PT auto-screened variants sourced via automotive-grade Microchip Direct channels. Halogen-free per Microchip environmental compliance disclosure.