PIC16F685-I/SS - 20MHz 8-bit Flash MCU 7KB | Microchip
MPN: PIC16F685-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.59 | $25.90 |
| 100 | $2.21 | $221.00 |
| 500 | $1.96 | $980.00 |
| 1,000 | $1.74 | $1,740.00 |
PIC16F685-I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory (flash), working RAM, and programmable peripherals (ADC, timers, communication ports). Microcontrollers belong to the broader class of embedded processors, which sit within the integrated circuit (IC) hierarchy of semiconductors. The PIC16F685 uses Microchip's mid-range 14-bit instruction architecture, recognized for its 35-instruction RISC core that simplifies firmware development while delivering deterministic 200 ns instruction execution.
Key features include 11 I/O pins supporting capacitive-touch sensing via the mTouch peripheral, an internal 8 MHz oscillator, a 12-bit ADC with up to 12 channels, dual comparators, an enhanced PWM module, and an on-chip 256-byte EEPROM for non-volatile data storage. The nanoWatt technology suite provides multiple low-power sleep modes that drop supply current to the low microamp range, making the device attractive for battery-powered or energy-harvesting designs.
Architecturally, the PIC16F685 combines a Harvard bus structure with separate program and data paths, a hardware multiplier, and an interrupt controller with 11 sources. The 20-pin SSOP package with industrial temperature grade (-40 C to +85 C) is suitable for compact PCB layouts and reflow soldering in volume production. The device is code-protected with Microchip's standard security fuses and supports in-circuit serial programming (ICSP) through two pins.
Typical applications include consumer white goods, LED lighting controllers, sensor signal conditioning, battery chargers, capacitive touch user interfaces, small motor control loops, and low-cost industrial sensor nodes. Its combination of ADC, comparators, PWM and nanoWatt sleep makes it a strong fit for mixed-signal front ends.
When designing with this part, plan the ICSP connections early so the ICSP header does not interfere with the application circuit. Decouple VDD with a 100 nF ceramic placed within 5 mm of the pin, and configure the configuration bits in source code so they remain under version control.
This page consolidates distributor pricing, drop-in alternatives, and engineering design notes not provided in the manufacturer datasheet alone.
Drop-in alternatives for PIC16F685-I/SS — 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-I/SS (same form factor and footprint) — differing in Package, Operating Temperature, I/O Pins, Internal Oscillator, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F685-E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F685T-I/SS
✅ Drop-In✓ In Stock
$1.15 / Unit
View Datasheet →PIC16F685T-E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F685-H/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F677-I/SS
✅ Drop-In✓ In Stock
$1.27 / Unit
View Datasheet →PIC16F677-E/SS
✅ Drop-In✓ In Stock
$1.41 / Unit
View Datasheet →PIC16F631-I/SS
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →PIC16F631T-I/SS
✅ Drop-In✓ In Stock
$0.92 / Unit
View Datasheet →PIC16F685-I/SS Maximum Ratings & Electrical Characteristics
| Family | PIC16F |
| Core | 8-bit PIC mid-range (14-bit instruction) |
| Clock Speed (max) | 20 MHz |
| Program Memory (Flash) | 7 KB (4K x 14) |
| RAM | 256 B |
| Data EEPROM | 256 B |
| I/O Pins | 11 |
| Operating Voltage | 2.0 V to 5.5 V |
| Package | 20-pin SSOP |
| Comparators | 2 |
| Internal Oscillator | 8 MHz |
| Capacitive Touch Sensing | mTouch supported |
| ICSP | Yes (2-wire in-circuit serial programming) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16F685-I/SS Pin Configuration
| Pin 1 | VDD — Positive supply voltage |
| Pin 2 | RA5/T1CKI/OSC1/CLKIN — I/O / Timer1 clock / crystal oscillator input / external clock input |
| Pin 3 | RA4/AN3/T1G/OSC2/CLKOUT — I/O / analog input / Timer1 gate / crystal oscillator output / clock output |
| Pin 4 | RA3/AN2/Vref+/C1OUT — I/O / analog input / ADC Vref+ / comparator 1 output |
| Pin 5 | RC5/AN4/C2OUT — I/O / analog input / comparator 2 output |
| Pin 6 | RC4/AN3 — I/O / analog input |
| Pin 7 | RC3/AN7/C12IN3-/P1D — I/O / analog input / comparator input / PWM output |
| Pin 8 | RC2/AN6/C12IN2-/P1C — I/O / analog input / comparator input / PWM output |
| Pin 9 | RC1/AN5/C12IN1-/P1B — I/O / analog input / comparator input / PWM output |
| Pin 10 | RC0/AN4 — I/O / analog input |
| Pin 11 | RA2/AN2/Vref-/C1OUT — I/O / analog input / ADC Vref- / comparator 1 output |
| Pin 12 | RA1/AN1/C12IN1-/ICSPCLK — I/O / analog input / comparator input / ICSP clock |
| Pin 13 | RA0/AN0/C12IN0+/ICSPDAT — I/O / analog input / comparator input / ICSP data |
| Pin 14 | VSS — Ground reference |
| Pin 15 | RB7/AN6/T1G/P1D — I/O / analog input / Timer1 gate / PWM output |
| Pin 16 | RB6/AN5/P1C — I/O / analog input / PWM output |
| Pin 17 | RB5/AN3/P1B — I/O / analog input / PWM output |
| Pin 18 | RB4/AN2/P1A — I/O / analog input / PWM output |
| Pin 19 | RB3/AN9/C12IN3-/CCP1 — I/O / analog input / comparator input / capture/compare/PWM |
| Pin 20 | RB2/AN8/C12IN2-/P1A — I/O / analog input / comparator input / PWM output |
Typical Applications
PIC16F685-I/SS is suitable for 6 applications: Capacitive Touch User Interface, Battery-Powered Sensor Node, LED Lighting Controller, Small DC Motor Control, Battery Charger Controller, Industrial Sensor Signal Conditioning.
Capacitive Touch User Interface
The PIC16F685-I/SS is well suited for capacitive touch buttons and sliders thanks to its on-chip mTouch peripheral and 12 ADC channels with 11 usable I/O. Its 20 MHz core executes 200 ns instructions, fast enough to scan 8-12 touch pads within a 10 ms cycle for responsive UI feedback. Power consumption drops below 1 uA in sleep with touch wake-up via the mTouch hardware, enabling battery-powered remote controls, kitchen appliances, and consumer white goods. The 20-pin SSOP keeps the PCB footprint small enough for handheld devices. Compared with mechanical buttons, capacitive touch improves reliability by sealing the enclosure against moisture and dust.
Recommended
Battery-Powered Sensor Node
With nanoWatt technology, the PIC16F685-I/SS can run from 2.0-5.5 V including a direct 3 V lithium or two AA cells, dropping below 1 uA in sleep with the ADC and comparators waking the core only when needed. The 12-bit ADC with up to 12 channels allows direct connection of multiple sensors (temperature, light, humidity) without external multiplexing. The 256-byte EEPROM stores calibration constants and runtime counters across power cycles. Industrial -40 C to +85 C temperature grade suits outdoor environmental monitoring, asset tracking, and smart agriculture deployments where coin-cell batteries must last years.
Recommended
LED Lighting Controller
The PIC16F685-I/SS drives constant-current LED strings via its enhanced PWM module and dual comparators, which close the loop on current-sense feedback without an external op-amp. The 20 MHz clock supports 10-bit PWM resolution at high switching frequencies, eliminating audible flicker in architectural and stage lighting. Its 11 I/O drive multiple channels of LEDs, status indicators, and DMX-style digital control inputs. Wide 2.0-5.5 V operation supports direct battery drive and USB-powered fixtures. SSOP-20 allows slimline PCB integration into linear LED strips, downlights, and grow-light fixtures.
Recommended
Small DC Motor Control
The PIC16F685-I/SS drives brushed DC motors and small steppers through its PWM and complementary outputs. Hardware comparators implement current-limit and stall detection in firmware-free analog loops, protecting the FET bridge from short-circuit events. The 8-bit core at 20 MHz provides 200 ns control-loop timing, sufficient for 5-10 kHz PWM in brushed DC and unipolar stepper drives. Industrial temperature grade suits automotive accessory motors, HVAC dampers, and small appliances. The 20-pin SSOP package eases integration on crowded motor-control PCBs.
Recommended
Battery Charger Controller
The PIC16F685-I/SS implements CC/CV charging profiles for single-cell Li-ion, LiFePO4, and NiMH packs using its 12-bit ADC to sense pack voltage and charge current. The dual comparators provide hardware safety limits independent of firmware, disconnecting the FET path on over-voltage or over-temperature without CPU intervention. On-chip EEPROM stores chemistry parameters and learned capacity data. The 2.0-5.5 V range allows direct USB-powered charger operation. SSOP-20 fits compact USB wall-wart and power-bank form factors.
Recommended
Industrial Sensor Signal Conditioning
The PIC16F685-I/SS conditions analog front-end signals in industrial 4-20 mA loops, RTDs, and bridge sensors. Its 12 ADC channels accept multiple sensor inputs simultaneously, while dual comparators implement window-discriminator functions for alarm outputs. The 20 MHz core executes digital filtering and linearization of sensor curves in real time. Industrial -40 C to +85 C operation tolerates factory floor temperatures, and the wide 2.0-5.5 V supply tolerates regulated 24 V industrial rails after a simple LDO step-down. SSOP-20 enables dense multi-channel PLC daughter boards.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F685-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F685-E/SS | PIC16F685T-I/SS | PIC16F685-H/SS | PIC16F677-I/SS | PIC16F631-I/SS |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same |
| Program Memory (Flash) | 7 KB | 7 KB | 7 KB | 7 KB | 3.5 KB (-50%) | 1.75 KB (-75%) |
| RAM | 256 B | 256 B | 256 B | 256 B | 128 B (-50%) | 64 B (-75%) |
| Comparators | 2 | 2 | 2 | 2 | 1 (-50%) | 0 |
| Operating Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Operating Temperature | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | -40 C to +85 C |
Key Differentiators
- Largest flash and most ADC channels in 20-pin PIC16F6xx family (vs PIC16F677-I/SS)
- Two on-chip comparators (vs PIC16F677-I/SS)
- Same SSOP-20 footprint across the entire 685 family (vs PIC16F685-E/SS)
Design Notes
Decouple VDD with a 100 nF X7R ceramic capacitor placed within 5 mm of the VDD pin, plus a bulk 10 uF if the supply is shared with other loads. The PIC16F685 datasheet recommends a low-ESR decoupling network to keep nanoWatt sleep currents within specification. Avoid long trace inductance between the cap and the pin; route a wide ground return directly back to VSS.
Route ICSP signals RB6 (ICSPCLK) and RA0 (ICSPDAT) with short, direct traces to the programming header. Place the header at the PCB edge for production-line access. Keep analog inputs AN0-AN7 away from switching traces such as PWM outputs to minimize ADC noise coupling. Use a ground plane and group analog/digital grounds at a single-point star if mixed-signal accuracy is required.
Always set configuration bits (CONFIG register) in source code, not only at programming time. A common failure mode is leaving the watchdog enabled unintentionally, causing the firmware to reset unexpectedly. For mTouch designs, calibrate the touch reference values at room temperature and store them in EEPROM, since temperature drift can shift the baseline capacitance.
When using the ADC, set the I/O pins to digital low before switching to analog mode to prevent shoot-through current in the input buffer. Configure the ADC acquisition time appropriately for the source impedance; with 10 kohm source impedance a 4 us acquisition time is recommended. Add a small RC filter at each analog input when the source has high-frequency noise.
Compliance Information
RoHS compliance indicated by SS package suffix per Microchip product page. Lifecycle status ACTIVE as of 2026-09-21. Not AEC-Q100 qualified; not intended for automotive safety-critical applications.
