This is the PCA9685 develop by XMP semiconductor. The PCA9685 is an i2C / TWI bus controller capable of driving 16 channels PWM controller. Suitable for driving servos and LED. Each LED output has its own 12-bit resolution at 4096 steps fixed frequency individual Pulse with Modulation controller that runs on programmable frequency from 24Hz to 1526 Hz along with adjustable 0%~100% duty cycle that allows the attach device to be set to a specific pulse value.  The PC9685 output can be off or on without PWM control or set as its individual pulse controller value. The output driver is programmable to either open-drain with 25mA current sink at 5v or totem pole with 25 mA sink, 10 mA source feature at 5 V. This device operates at 2.4v to 5.5v and the I/O are 5.5v tolerant. The components which is attach to this PCA9685 can be controlled via 5v internal or external driver and a minimum amount of discrete component for large current or higher voltage.

The PCA9685 is a fast-mode plus (Fm+) family. Fm+ devices offer higher frequency up to 1 MHz or more populated bus operation up to 4000 pF. The PCA9635 and PCA9685 almost similar features. Another feature of this device it is manage via i2C bus and can be address at the same time and allows you to group the device addressed at the same time in any combination. This device can be use in Servos, Small Bipe Robots Runs by Servos, RGB / RGBA LEDS, LED Displays, LCD Backlights, LED status information, and keypads backlights for cellphones. See datasheet for more details.

PCA9685 Boards

Required Components

  • Arduino IDE | Atmel Studio
  • Microcontroller – Arduino NANO, MINI, MEGA, UNO, LEO, DUE, ZERO, 101, MKR1000, FIO,  NodeMCU, Teensy Board, TeensyDuino, ESP8266 12, 12E, ESP32, LinkItOne, ESP8266 NodeMCU, ESPDuino, ATMEGA328 16/12, ATMEGA32u4 16/8/ MHz, ESP8266, ATMEGA250 16 MHz, ATSAM3x8E, ATSAM21D, ATTINY85 16/8 MHz Note: The Diagram below is using NANO. (please refer to each MCU’s respective pin-outs)
  • Steam Sensor, Water Vapor Sensor (see below diagram)
  • Capacitors (See below required values)
  • Resistors (See below required values)
  • Solder Less Breadboard (Optional)
  • Jumper Wire
  • Prototyping Board
  • HTSSOP / WQFN Sockets or Boards
  • PCB board

Wiring Guide

Slave Address: | 1 > Fixed |
Selectable: | A5 | A4 | A3 | A2 | A1 | A0 |

PCA9685 Wiring

Sketch Code For LED

Sketch Code For Servos

i2C Address Finder / Scanner


Wiring PCA9685 16-Channel/12Bit PWM i2C Bus Controller
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