PIC16F685-E/SO - 8-bit PIC MCU, 7KB Flash, 20MHz, 20-SOIC
MPN: PIC16F685-E/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.21 | $3.21 |
| 10 | $2.88 | $28.80 |
| 100 | $2.45 | $245.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.85 | $1,850.00 |
PIC16F685-E/SO Overview
What is a PIC16 microcontroller? A PIC16 is a family of 8-bit RISC microcontrollers from Microchip Technology based on a modified Harvard architecture with 14-bit instruction words. PIC16 devices belong to the broader category of microcontrollers (MCU) within the embedded processor hierarchy: PIC16 -> PIC microcontrollers -> 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. They are widely used for cost-sensitive, low-power, deterministic control tasks where a full 32-bit MCU is over-spec, complementing ARM Cortex-M and higher-end Microchip dsPIC/PIC32 families.
Key feature highlights of the PIC16F685 include an integrated 8-channel 10-bit Analog-to-Digital Converter (ADC) with input multiplexing, an Enhanced Universal Synchronous/Asynchronous Receiver Transmitter (EUSART) with an internal baud-rate generator, a Master Synchronous Serial Port (MSSP) supporting SPI and I2C (master/slave), four 8-bit timers (Timer0/Timer2 with prescaler and Timer1/Timer3 with dedicated 16-bit support), dual analog comparators with reference, and a Capture/Compare/PWM (CCP) module. The E suffix indicates the Extended temperature grade (-40°C to +125°C).
Architecturally, the PIC16F685 uses a single-cycle 200 ns instruction execution path with a hardware stack of 8 levels and direct/indirect addressing modes. On-chip debug is supported via the In-Circuit Debugger (ICD) interface, and the Flash supports 100K erase/write cycles typical, with EEPROM supporting 1M cycles typical. nanoWatt features such as alternate oscillator modes, two-speed startup, and fail-safe clock monitoring reduce active and idle current for battery-powered applications.
Typical applications include consumer appliance control, LED driving and lighting controllers, automotive body and accessory modules, sensor signal conditioning, low-cost industrial automation nodes, and battery-powered IoT edge devices where deterministic 8-bit control, small footprint, and robustness matter more than raw compute. The 20-SOIC package also eases hand-solderable prototyping versus QFN alternatives.
When designing with the PIC16F685-E/SO, ensure the MCLR pin has a proper pull-up configuration and that VDDCORE bypass capacitors follow the datasheet reference. Use ICD for firmware bring-up, and leverage the nanoWatt sleep states when average system current must stay in the microamp range. For applications requiring >10-bit ADC or USB, consider migrating to PIC18 or PIC24 families.
Drop-in alternatives for PIC16F685-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 PIC16F685-E/SO (same form factor and footprint) — differing in Package, Operating Temperature, Timers, ADC, Internal Oscillator.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F685-I/SO
✅ Drop-In✓ In Stock
$1.68 / Unit
View Datasheet →PIC16F677-I/SO
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC16F677-E/SO
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC16F676-E/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F648A-E/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16F628-04E/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F685-E/SO Maximum Ratings & Electrical Characteristics
| Architecture | PIC16 mid-range (x14) 8-bit RISC |
| Program Memory | 7 KB Flash (4K x 14) |
| RAM | 256 bytes |
| EEPROM Data Memory | 256 bytes |
| Maximum CPU Frequency | 20 MHz |
| Instruction Cycle | 200 ns |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| Digital I/O Pins | 18 |
| ADC | 10-bit, up to 8 input channels |
| Communication Interfaces | EUSART (RS-232/RS-485), MSSP (SPI / I2C) |
| Timers | Timer0/Timer2 (8-bit), Timer1/Timer3 (16-bit) |
| Analog Comparators | 2 (with programmable reference) |
| PWM Modules | 1 x CCP (Capture/Compare/PWM) |
| Operating Temperature | -40C to +125C (Extended, E grade) |
| Package | 20-SOIC (300 mil) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16F685-E/SO Pin Configuration
| Pin 1 | RA0/AN0/C1IN+/ICSPDAT — Bidirectional I/O; analog input 0; comparator 1 non-inverting input; ICSP data |
| Pin 2 | RA1/AN1/C1IN-/ICSPCLK — Bidirectional I/O; analog input 1; comparator 1 inverting input; ICSP clock |
| Pin 3 | RA2/AN2/CVREF/VREF- — Bidirectional I/O; analog input 2; comparator VREF output; ADC VREF- |
| Pin 4 | RA3/MCLR/VPP — Input only; Master Clear reset (active low) / programming voltage |
| Pin 5 | RA4/AN3/T0CKI/C1OUT — Bidirectional I/O; analog input 3; Timer0 clock input; comparator 1 output |
| Pin 6 | RA5/AN4/C2OUT/SS — Bidirectional I/O; analog input 4; comparator 2 output; SPI slave select |
| Pin 7 | VSS — Ground reference |
| Pin 8 | OSC1/RA7/CLKIN — Crystal/Resonator input or external clock in; also digital I/O |
| Pin 9 | OSC2/RA6/CLKOUT — Crystal/Resonator output or clock out; also digital I/O |
| Pin 10 | RC0/T1OSO/T1CKI — Bidirectional I/O; Timer1 oscillator output or clock input |
| Pin 11 | RC1/T1OSI/CCP2 — Bidirectional I/O; Timer1 oscillator input; CCP2 PWM output |
| Pin 12 | RC2/CCP1 — Bidirectional I/O; CCP1 PWM output |
| Pin 13 | RC3/AN7/C12IN3-/SCK/SCL — Bidirectional I/O; analog input 7; comparator input; SPI SCK / I2C SCL |
| Pin 14 | RC4/AN6/C2IN+/SDI/SDA — Bidirectional I/O; analog input 6; comparator inverting input; SPI SDI / I2C SDA |
| Pin 15 | RC5/AN5/C2IN-/SDO — Bidirectional I/O; analog input 5; comparator inverting input; SPI SDO |
| Pin 16 | RC6/TX/CK/AN8 — Bidirectional I/O; EUSART TX / clock; analog input 8 |
| Pin 17 | RC7/RX/DT/AN9 — Bidirectional I/O; EUSART RX / data; analog input 9 |
| Pin 18 | RB0/INT/AN10 — Bidirectional I/O; external interrupt; analog input 10 |
| Pin 19 | RB1/AN11 — Bidirectional I/O; analog input 11 |
| Pin 20 | VDD — Positive supply voltage |
Typical Applications
PIC16F685-E/SO is suitable for 6 applications: Consumer Appliance Control, LED Lighting Drivers, Battery-Powered IoT Edge Sensors, Industrial Sensor Interface, Automotive Body & Accessory Modules, Educational & Hobby Projects.
Consumer Appliance Control
The PIC16F685-E/SO suits small home appliances such as blenders, toaster ovens and coffee makers where a deterministic 8-bit core, low BOM cost and 5V tolerance simplify design. With 7 KB Flash and 256 bytes each of RAM/EEPROM, the MCU can store PID parameters, user presets and run a control loop at 20 MHz (5 MIPS). The dual analog comparators handle zero-cross and over-temperature detection, and the PWM drives triac-controlled heaters. Total system cost stays under $2 by avoiding external ADC and reference parts.
Recommended
LED Lighting Drivers
Use the PIC16F685-E/SO as a digital LED driver for architectural and strip lighting. The CCP module provides hardware PWM at up to 20 kHz with 10-bit resolution, while the 8-channel 10-bit ADC reads ambient light sensors and potentiometer dimmers. nanoWatt Technology low-power modes keep standby current near a few microamps for EnergyStar compliance. The 2.0 V to 5.5 V supply range supports both 3.3 V logic-level LED strings and 5 V analog dimming chains.
Recommended
Battery-Powered IoT Edge Sensors
Battery-powered wireless sensor nodes and IoT edge devices leverage the PIC16F685-E/SO's nanoWatt Technology sleep current to extend coin-cell runtime to months or years. The MSSP block talks SPI to an external RF transceiver (for example a Sub-GHz radio) and the EUSART carries RS-485 backhaul. With 256 bytes of EEPROM, calibration constants persist across battery swaps. The -E grade (-40 C to +125 C) handles outdoor enclosures and industrial cabinets equally.
Recommended
Industrial Sensor Interface
The PIC16F685-E/SO is a strong fit for 4-20 mA / 0-10 V industrial sensor conditioning boards. The 10-bit ADC provides 8 channels for strain gauge, pressure or temperature bridges, while the 256 bytes of EEPROM let installers store calibrated offsets on the shop floor. The MSSP I2C peripheral talks to external ADCs or DACs on calibration boards, and the wide 2.0-5.5 V supply tolerates noisy 24 V -> 5 V industrial rails. The -40 C to +125 C range suits outdoor enclosures.
Recommended
Automotive Body & Accessory Modules
Although not AEC-Q100 qualified, the PIC16F685-E/SO is widely used for non-safety automotive accessories like interior lighting, mirror controllers and HVAC blend doors, thanks to its -40 C to +125 C extended temperature range and 5 V tolerance. The 20 MHz core supports CAN/LIN transceivers over UART, while the PWM drives small DC motors. Use Automotive-qualified parts (not the -E suffix) only for safety-critical paths.
Recommended
Educational & Hobby Projects
The PIC16F685-E/SO in the wide-body 20-SOIC package is solder-friendly for breadboard adapters and through-hole-friendly PCBs, making it a strong choice for STEM kits and hobbyist firmware training. With 7 KB Flash, students can run full-feature projects like LCD menus, motor control and basic RTOS shells. MPLAB X IDE compatibility, generous ICD support and abundant application notes accelerate learning curves compared to bare 32-bit ARM parts.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F685-E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F685-I/SO | PIC16F677-I/SO | PIC16F677-E/SO | PIC16F676-E/SO | PIC16F648A-E/SO | PIC16F628-04E/SO |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SOIC | 20-SOIC | 20-SOIC | 20-SOIC | 20-SOIC | 20-SOIC | 20-SOIC |
| Flash Program Memory | 7 KB | 7 KB | 7 KB | 7 KB | 1.75 KB | 5 KB | 3.5 KB |
| RAM | 256 B | 256 B | 256 B | 256 B | 64 B | 256 B | 224 B |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 128 B | 256 B | 128 B |
| Max CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 4 MHz |
| ADC Channels / Resolution | 8 ch / 10-bit | 8 ch / 10-bit | 8 ch / 10-bit | 8 ch / 10-bit | 8 ch / 10-bit | no ADC | no ADC |
| Enhanced EUSART | Yes | Yes | No | No | No | Yes | Yes (USART) |
| Operating Temperature | -40C to +125C (E) | -40C to +85C (I) | -40C to +85C (I) | -40C to +125C (E) | -40C to +125C (E) | -40C to +125C (E) | -40C to +125C (E) |
| Approx. Unit Price (1 pc) | $3.21 | $3.05 | $2.85 | $3.10 | $2.10 | $2.95 | $2.65 |
Key Differentiators
- Enhanced EUSART support (vs PIC16F677-I/SO)
- Larger Flash with same peripherals (vs PIC16F676-E/SO)
- Modern ADC, PWM, comparator peripheral set (vs PIC16F628-04E/SO)
- 5x faster core (vs PIC16F628-04E/SO)
Design Notes
Place VDD and VSS decoupling capacitors (100 nF ceramic, plus 10 uF bulk) within 5 mm of the respective pins on the PIC16F685-E/SO's 20-SOIC footprint. The AVdd/A-Vss pair (referenced as VDD/VSS in the SOIC variant) should have an additional 100 nF close to the analog supply route. Estimated: with a 100 nF X7R 0402 at 5 mm trace inductance ~3 nH, peak decoupling is effective up to ~50 MHz, well beyond the PIC16F685's 20 MHz core. A continuous ground plane is mandatory for ADC noise below 1 LSB.
Use the PIC16F685's nanoWatt Technology sleep modes (SLEEP with peripheral disable) to drop standby current below 1 uA for battery-powered designs. Estimated: with Timer1 running at 32 kHz and ADC off, sleep current is ~1 uA at 3 V. The Wide operating voltage of 2.0V-5.5V supports direct Li-ion or 2x AA chemistries. For 5 V regulated rails, add a ferrite bead + 10 uF cap to attenuate ADC sampling ripple on the digital rail.
The MCLR pin (pin 4) must never be left floating - use a 10 kO pull-up to VDD and a 100 nF cap to VSS for clean reset behavior. Watch the I/O share of OSC1/OSC2 with RA6/RA7; when using an external crystal, those pins become unavailable as GPIO. The ADC can alias on high-impedance sources if acquisition time is too short - keep ADC source impedance below 10 kO to settle within 1.5 us.
MSSP in I2C fast-mode requires 4.7 kO pull-ups on SCL/SDA (RC3/RC4 in 20-SOIC) for reliable 400 kHz operation at 5 V. For SPI runs longer than ~50 mm, lower SCL/SCK slew to 1 MHz max or use series 33 O resistors near the driver. Estimated: bus capacitance scales ~1 pF/cm, so 50 mm of ribbon adds ~5 pF total, well within I2C spec. Keep SCL/SDA traces short and parallel.
Route the 10-bit ADC analog inputs (RA0-RA5, RC3-RC5, RC6-RC7) on a separate analog plane or guarded routing away from digital switching nodes. Estimated: a 1 mm ground guard trace reduces coupling by ~15 dB. Place the external voltage reference (if any) within 3 cm of the analog pins. Finally, do not share analog and digital ground returns - tie them at a single point under the MCU VSS pin.
Compliance Information
RoHS/REACH compliance per Microchip product page; Extended temperature grade -40C to +125C; not AEC-Q100 qualified for safety-critical automotive.
