24-channel UFm 5 MHz I2C-bus 57 mA/20 V constant current LED driver

Optimized for dimming and blinking 57 mA Red/Green/Blue/Amber (RGBA) LEDs in amusement products, the PCU9956A is an Ultra Fast-mode (UFm) I²C-bus controlled 24-channel constant current LED driver which is the first LED controller device in a new UFm I²C-bus family. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWm controller that operates at 31.25 kHz with a duty cycle that is adjustable from 0% to 99.6% to allow the LED to be set to a specific brightness value.

UFm I²C-bus devices offer higher frequency (up to 5 MHz). the UFm I²C-bus slave devices operate in receive-only mode. That is, only I²C writes to PCU9956A are supported. As such, there are no status registers in PCU9956A. The PCU9956A allows significantly higher data transfer rate compared to the Fast-mode Plus version (PCA9956A).

Block diagram of PCU9956A

Block diagram of PCU9956A

Why Used

  • 24 constant current output channels can sink up to 57 mA, tolerate up to 20 V when OFF
  • Output current adjusted through an external resistor (REXT input)
  • Thermal shut-down for overtemperature
  • Software Reset feature (SWRST Call) allows the device to be reset through the I²C-bus
  • ESD protection exceeds 3000 V HBM per JESD22-A114

Where Used

  • Amusement products
  • RGB or RGBA LED drivers
  • LED status information
  • LED displays
  • LCD backlights
  • Keypad backlights for cellular phones or handheld devices

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