PCA9685PW/Q900,118

Overview

The PCA9685PW/Q900,118 is an I²C-bus controlled 16-channel LED controller optimized for RGBA color backlighting. It features a 12-bit PWM resolution (4096 steps) with programmable frequencies from 24 Hz to 1526 Hz. The device operates on a supply voltage of 2.3 V to 5.5 V and supports Fm+ I²C interfaces up to 1 MHz. Outputs provide 25 mA sink current in open-drain mode or 25 mA sink/10 mA source in totem-pole mode. It includes staggered switching capabilities and external clock input.

Feature Summary

• Supports 12-bit PWM resolution with individually programmable duty cycles for precise brightness control across all channels.
• Enables staggered output switching times to minimize current surges during simultaneous LED activation.
• Includes an external clock input pin to synchronize multiple devices using a user-provided signal.
• Features software-programmable full-call and sub-call addresses for efficient multi-device bus management.

Applications

• RGBA color LCD backlighting systems
• Ambilight lighting effects
• LED matrix displays

Procurement Notes

Verify the specific suffix Q900 against the manufacturer's official documentation to confirm package type and automotive qualification status. Ensure the ordering part number matches the exact TSSOP-28 variant required for your design. Cross-reference the datasheet revision date to validate parameter accuracy before finalizing procurement specifications.

Selection Notes

Select this component when high-resolution 12-bit dimming and synchronized multi-device operation are required. The Fm+ interface supports higher bus speeds and larger capacitance loads compared to standard I²C. Consider the external clock capability if system-wide timing synchronization is necessary for complex lighting arrays.

Part Context

This part belongs to the PCA9685 series of LED drivers. It is designed as an upgrade to previous models like the PCA9635, offering superior brightness control and synchronization features. The device is manufactured by NXP Semiconductors and is suitable for automotive and consumer electronics applications requiring precise LED management.

Replacement Considerations

The PCA9685BS,118 serves as a functional alternative within the same family, differing primarily in the HVQFN28 package format rather than electrical performance characteristics.

FAQ

How does the PCA9685 manage current surges?

It allows independent programming of on and off time delays for each of the 16 channels, enabling staggered switching to minimize current spikes.

What is the maximum I²C bus frequency supported?

The device supports Fast-mode Plus (Fm+) operation with a maximum frequency of 1 MHz.

Can the PWM frequency be adjusted?

Yes, the PWM frequency is programmable via a prescaler register, typically ranging from 24 Hz to 1526 Hz.