PCA9685PW: 16-Channel 12-Bit PWM I2C LED Driver

ElecSuppliers Part Number ComparisonAug 21, 2026

The PCA9685PW is a 16-channel, 12-bit PWM controller from NXP designed for LED control and other applications that require multiple independently controlled PWM outputs.

The device uses an I²C-bus interface, allowing a microcontroller to control up to 16 PWM channels through a relatively small number of communication lines. Its combination of multiple outputs, 12-bit resolution and programmable PWM frequency makes it useful in LED lighting, display and actuator-control applications.

What Is the PCA9685PW?

The PCA9685PW is an I²C-controlled 16-channel PWM LED driver.

Each of its 16 outputs has an individual 12-bit PWM controller, providing 4096 programmable steps for brightness or duty-cycle control.

Instead of generating 16 independent PWM signals directly from a microcontroller, the MCU can configure the PCA9685PW through the I²C interface.

This can save MCU timer resources and reduce the number of processor pins required for multi-channel PWM applications.

PCA9685PW 16 PWM Channels

The device provides 16 independently programmable PWM outputs.

Each output can be configured for its own on and off timing within the common PWM frequency.

This architecture allows multiple LEDs to be controlled individually from the same IC.

For applications involving many actuators or other PWM-controlled loads, the 16 channels can also provide a convenient way to expand the number of available PWM outputs without requiring a larger MCU.

PCA9685PW 12-Bit PWM Resolution

The PCA9685PW provides 12-bit PWM resolution.

This corresponds to 4096 programmable steps for each PWM channel.

Higher resolution allows finer adjustment of LED brightness and PWM duty cycle compared with an 8-bit PWM controller.

For LED dimming, the additional resolution can provide smoother control over brightness levels.

The practical visual result will also depend on the LED, current driver, optical system and application requirements.

PCA9685PW I2C Interface

The PCA9685PW communicates with the host controller through an I²C-bus interface.

This means the MCU can configure the PWM channels using the SDA and SCL communication lines rather than requiring a separate hardware PWM output for every channel.

The device supports Fast-mode Plus I²C operation up to 1MHz.

This makes it suitable for systems where multiple PWM channels need to be configured efficiently.

PCA9685PW PWM Frequency

The PWM frequency can be programmed over a broad range.

NXP specifies a typical programmable range of approximately 24Hz to 1526Hz.

The selected frequency can be adjusted according to the application.

LED lighting may use a different PWM frequency from servo-control or other actuator applications, so the ability to configure the PWM frequency provides additional flexibility.

All 16 channels operate at the same PWM frequency, while their individual on and off timing can be programmed independently.

PCA9685PW LED Brightness Control

The 12-bit PWM architecture allows each LED output to have its own brightness setting.

A microcontroller can send the required register values through I²C and adjust individual channels without continuously generating PWM waveforms in software.

This is useful for RGB and RGBA lighting systems where multiple color channels need independent control.

The same architecture can also be used for larger LED arrays where many individual outputs must be adjusted.

PCA9685PW Servo Control Applications

The PCA9685 family is also widely associated with multi-channel servo-control applications.

The device provides 16 PWM outputs that can be configured by the host controller.

This allows a system to control multiple servo channels while using only an I²C connection between the MCU and PWM controller.

When driving servos, the complete timing requirements of the selected servo must be considered. The PCA9685PW generates the PWM signal, but the external power supply and load-driving circuitry must provide the required servo current.

PCA9685PW Output Enable

The PCA9685PW includes an active-low Output Enable input.

This provides hardware control over the output state independently of normal I²C configuration.

The OE input can be useful when the system needs to quickly disable the outputs or control multiple PWM drivers together.

It can also be used for external PWM control of the outputs when the application requires it.

PCA9685PW Multiple Device Configuration

One useful feature of the PCA9685 architecture is its address configuration.

The device provides six hardware address pins, allowing multiple PCA9685 devices to share the same I²C bus.

NXP specifies that up to 62 devices can be connected using the available hardware addresses.

This provides a scalable architecture for systems requiring a large number of PWM outputs.

For example, several PCA9685 devices can be used to expand a system from 16 PWM channels to dozens or hundreds of channels while maintaining the same basic I²C control architecture.

PCA9685PW Operating Voltage

The PCA9685 operates from a supply-voltage range of 2.3V to 5.5V.

Its inputs and outputs are 5.5V tolerant under the specified conditions.

This allows the device to be integrated into different embedded systems with suitable logic-level configurations.

The LED or actuator supply should still be designed separately according to the requirements of the external loads.

PCA9685PW LED Driver Output

The output stage can be configured for open-drain or totem-pole operation.

In the specified 5V conditions, the output stage provides up to 25mA sink capability, with totem-pole operation supporting 10mA source capability.

For applications requiring higher LED current or higher load voltage, external transistor or MOSFET drivers can be used.

The PCA9685PW should therefore be regarded as a PWM controller and LED driver rather than a replacement for a high-power external switching stage.

PCA9685PW Applications

The PCA9685PW can be used in many multi-channel PWM applications.

Typical applications include LED backlighting, RGB and RGBA lighting, display systems, servo control, actuator control and other embedded systems requiring numerous independently controlled PWM outputs.

Its I²C interface makes it particularly useful when the host MCU has limited PWM peripherals.

PCA9685PW Package

The PCA9685PW uses a 28-pin TSSOP package.

The surface-mount package is suitable for automated PCB assembly and compact electronic products.

NXP also offers PCA9685 variants in other package configurations, so the complete Part Number should be checked when selecting a replacement.

For an existing PCB, the package, pin assignment and footprint must match the intended device.

PCA9685PW PCB Design

The PCA9685PW should have appropriate local power-supply decoupling.

The I²C traces should be routed carefully, especially when multiple devices share the same bus.

PWM output traces should also be considered according to the connected load.

When external MOSFETs, LEDs or servo loads are used, the power-current paths should be kept separate from sensitive logic and I²C routing where practical.

Choosing the PCA9685PW

The PCA9685PW is a strong choice when a design needs many independently controlled PWM outputs but the host MCU has limited hardware PWM resources.

Its 16 channels, 12-bit resolution, I²C interface and programmable PWM frequency make it useful for both lighting and actuator-control applications.

For larger systems, multiple devices can be connected to the same I²C bus using their configurable hardware addresses.

When purchasing or adding the component to a BOM, use the complete PCA9685PW Part Number and verify the specific ordering suffix, package and active ordering status required for production.