PCA9745BTWJ

Overview

The PCA9745BTWJ is a 16-channel constant current LED driver optimized for RGBA LEDs in amusement products. It features an SPI-compatible 4-wire serial bus interface and HTSSOP28 package. Each channel includes an 8-bit PWM controller operating at 31.25 kHz with 0-100% duty cycle adjustment. An additional group PWM controller supports fixed 122 Hz or adjustable frequencies (15 Hz to once per 16.8 seconds) for synchronized dimming or blinking. The device operates on a 3 V to 5.5 V supply, supporting up to 20 V on LED outputs. Peak current is adjustable via an 8-bit linear DAC from 225 µA to 57 mA.

Feature Summary

• Supports daisy-chain SPI communication for simplified system wiring
• Provides independent 8-bit resolution brightness control for each of the 16 channels
• Includes programmable ramp-up and ramp-down capabilities without MCU intervention
• Features selectable gradation control groups for synchronized output adjustments

Applications

• Amusement product lighting systems
• RGBA LED color mixing applications
• Synchronized LED dimming and blinking effects
• Daisy-chained LED driver networks

Procurement Notes

Verify the specific suffix 'J' against the manufacturer's official datasheet to confirm package type and temperature range specifications. Ensure the design accommodates the required SPI timing parameters, particularly regarding the SDO pin behavior during chip select transitions. Confirm that the target application voltage does not exceed the 20 V limit on the LED sink outputs.

Selection Notes

Select this component when a high channel count with individual grayscale control is required alongside synchronized global dimming functions. It is suitable for designs needing adjustable peak current settings via internal DACs rather than external resistors. Consider the HTSSOP28 package constraints for PCB layout and thermal management requirements relative to the maximum 57 mA per channel capability.

Part Context

This part belongs to NXP's PCA9745B family of LED drivers, designed specifically for complex lighting scenarios requiring precise color and intensity control. It complements other NXP interface solutions by providing dedicated constant current sinking for high-brightness LEDs while managing communication overhead through efficient serial protocols.

Replacement Considerations

Check for direct substitutes within the PCA9745B series that may offer different package options or extended temperature ranges. Verify compatibility with existing SPI firmware if migrating between variants, as register maps must remain identical for seamless integration.