PCA9685 16-channel LED Controller Datasheet by NXP Semiconductors 2025

The PCA9685, developed by NXP Semiconductors, is an advanced 16-channel LED controller that leverages I2C communication to offer precise PWM control, making it a versatile solution for applications requiring fine-tuned LED brightness management. With its 12-bit resolution and wide PWM frequency range, this device stands out in the field of LED control, especially for dynamic applications like RGB and RGBA backlighting.

Its low-power operation, coupled with robust features like staggered LED switching and external clock synchronization, positions the PCA9685 as an ideal choice for energy-efficient and high-performance LED systems across a wide range of industries, including automotive, industrial, and consumer electronics.

PCA9685 Overview

The PCA9685 is a 16-channel LED controller that operates via the I2C bus, offering precise PWM control for applications such as RGB(A) backlighting. Each output features a 12-bit resolution PWM generator, enabling fine-grained brightness control across 4096 steps. The PWM frequency is programmable from approximately 24 Hz to 1526 Hz, with all channels sharing the same frequency. The device supports both open-drain and totem-pole output configurations, providing a 25 mA sink and 10 mA source capability at 5 V. Operating within a supply voltage range of 2.3 V to 5.5 V, the PCA9685 is 5.5 V tolerant on both inputs and outputs, allowing direct LED connection or integration with external drivers for high-power applications. Additionally, as part of the Fast-mode Plus (Fm+) I2C family, it supports communication speeds up to 1 MHz and can operate on buses with capacitance up to 4000 pF.

Compared to the PCA9635, the PCA9685 introduces several enhancements, making it more suitable for backlighting and Ambilight applications. It supports staggered LED switching to reduce current surges, offers a wider PWM resolution of 12 bits instead of 8 bits, and includes a programmable prescaler to synchronize PWM pulse widths across multiple devices. A key feature is its external clock input, accepting frequencies up to 50 MHz for synchronization, whereas the PCA9635 lacks this capability. Additionally, the PCA9685 provides a more flexible PWM frequency range, making it compatible with external power controllers. Notably, its Power-On Reset (POR) state defaults to LOW on all LED outputs, contrasting with the PCA9635’s default HIGH state.

PCA9685 Pinout

The PCA9685 has a total of 28 pins in both TSSOP28 and HVQFN28 packages, providing the necessary connections for I2C communication, LED drivers, and power supply. Below is the pinout summary of the device, detailing the addresses, LED drivers, and power pins:

PCA9685 Block Diagram

Features of PCA9685

The PCA9685 offers a range of advanced features tailored for precise LED control and efficient I2C communication. It supports 16 independent LED drivers with programmable brightness, turn-on times, and output configurations, all optimized for minimizing electromagnetic interference (EMI). The device operates with a 1 MHz Fast-mode Plus I2C interface and supports multiple addressable devices on a single bus, making it ideal for large-scale applications. Additionally, it includes a variety of safety, power management, and performance features, ensuring robust and reliable operation in diverse environments.

Key Features of PCA9685

• 16 Programmable LED Drivers: Each output can be controlled for off, on, brightness, or turn-on time, minimizing EMI.
• I2C Interface: 1 MHz Fast-mode Plus compatible with 30 mA high drive capability for high capacitive buses.
• 12-bit Brightness Control: 4096-step brightness control per LED, offering precise dimming from off to full brightness.
• LED Output Frequency: Ranges from 24 Hz to 1526 Hz, with a default of 200 Hz at a 25 MHz oscillator clock.
• Totem Pole Outputs: 25 mA sink and 10 mA source capability at 5 V, with software-selectable open-drain outputs.
• Active LOW Output Enable (OE): Allows for programmable LED states and high-impedance output when OE is HIGH.
• Multiple I2C-bus Addresses: Supports up to 62 devices with six hardware address pins and four software-programmable addresses.
• LED Blinking: Toggling the OE pin enables hardware-controlled LED blinking.
• Software Reset: SWRST General Call for resetting the device via the I2C-bus.
• Wide Operating Voltage Range: Operates within 2.3 V to 5.5 V with 5.5 V tolerant inputs, supporting diverse applications.

PCA9685 Application

The PCA9685 is a versatile LED driver capable of managing a wide range of LED-based applications, particularly where precise brightness control and efficient power management are required. Its 16-channel output configuration and 12-bit PWM control make it ideal for use in lighting and display systems, such as RGB or RGBA LED backlighting.

• RGB or RGBA LED Drivers: Ideal for controlling multi-color LEDs, allowing dynamic color mixing and individual channel brightness adjustments.
• LED Status Indicators: Suitable for applications where LED status indicators are required, offering flexible control over LED brightness and on/off states.
• LED Displays: The PCA9685 can be used to manage LED matrices for creating scalable displays with fine brightness control and minimal power consumption.
• LCD Backlighting: Perfect for adjusting the brightness of LCD backlights, ensuring energy efficiency and extended display life.
• Keypad Backlights: Commonly used in mobile phones and handheld devices, the PCA9685 controls the backlighting of keypads, enhancing visibility in low-light conditions while minimizing power use.

PCA9685 Advantages and Disadvantages

Advantages of PCA9685:

• Precise LED Brightness Control: 12-bit PWM resolution provides fine control over LED brightness, allowing for smooth dimming and better visual performance.
• Wide Application Range: Suitable for various applications like RGB/RGBA LED driving, LCD backlighting, and keypad backlighting in mobile devices.
• Low Power Consumption: Operates with a wide supply voltage range (2.3 V to 5.5 V) and low standby current, ideal for energy-efficient designs.
• High Drive Capability: Can drive high-capacitance buses with a 30 mA drive capability on the I2C SDA output, making it effective for large LED systems.
• Multiple Device Support: Supports up to 62 devices on a single I2C-bus, allowing for scalable solutions in large lighting setups or displays.

Disadvantages of PCA9685:

• Limited Current Handling: The output can sink only 25 mA and source 10 mA, which may require external drivers for high-power LEDs.
• Complexity for Simple Applications: Its advanced features, like external clock input and multiple addresses, may be unnecessary for basic LED control, adding complexity.
• I2C-Bus Limitations: The reliance on I2C for communication may cause issues like bus congestion in systems with many connected devices.
• Temperature Range: The operating temperature range of -40°C to +85°C may not be sufficient for extremely harsh environments.
• Power-On Reset Limitations: The Power-On Reset feature may not offer enough flexibility for specific configurations, requiring more precise initialization for some applications.

Package - SOT788

PCA9685 Datasheet PDF

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Manufacturer

NXP Semiconductors is a global leader in semiconductor solutions, renowned for its innovative technologies in automotive, industrial, and IoT applications. With a strong emphasis on providing high-performance products, NXP specializes in microcontrollers, sensors, and connectivity solutions, catering to a broad range of industries. The company’s extensive portfolio includes products designed to meet the demands of modern electronics, offering state-of-the-art features and performance. NXP’s commitment to advancing technology is evident in its development of cutting-edge components like the PCA9685, which exemplifies their expertise in creating efficient, high-quality devices for LED control.

The PCA9685, developed by NXP, is a prime example of their capability to deliver reliable and versatile solutions for complex electronic needs. This 16-channel, I2C-controlled PWM driver is designed to provide precise control over RGB and RGBA LEDs, making it ideal for use in display and backlighting applications. With NXP's focus on energy efficiency and high integration, the PCA9685 is optimized for low-power operation while offering high drive capability. NXP’s deep experience in designing semiconductor products ensures that the PCA9685 meets the highest standards for reliability, scalability, and performance, making it a trusted choice for engineers and developers worldwide.

Conclusion

The PCA9685 offers a comprehensive suite of features, combining precision, efficiency, and scalability to meet the demands of modern LED-driven applications. Whether used in backlighting, displays, or keypad illumination, it provides fine-grained control over LED behavior while minimizing power consumption.

NXP Semiconductors, known for its expertise in delivering high-performance semiconductor solutions, ensures that the PCA9685 delivers reliable performance in both large-scale and compact designs. Its flexibility, combined with NXP's reputation for quality, makes the PCA9685 an excellent choice for developers seeking a reliable, energy-efficient LED control solution.

PCA9685PW,112

NXP Semiconductors

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