LP3943

• Internal Power-On Reset
• Active Low Reset
• Internal Precision Oscillator
• Variable Dim Rates
  (From 6.25 ms to 1.6 s; 160 Hz to 0.625 Hz)
• 16 LED Drivers (Multiple Programmable States: ON, OFF, Input, and Dimming at a Specified Rate)
• 16 Open-Drain Outputs Capable of Driving up to 25 mA per LED

The LP3943 is an integrated device capable of independently driving 16 LEDs. This device also contains an internal precision oscillator that provides all the necessary timing required for driving each LED. Two prescaler registers, along with two PWM registers, provide a versatile duty-cycle control. The LP3943 contains the ability to dim LEDs in SMBUS/I²C applications where it is required, to cut down on bus traffic.

Traditionally, dimming LEDs using a serial shift register such as 74LS594/5 requires a large amount of traffic on the serial bus. The LP3943 instead requires only the setup of the frequency and duty cycle for each output pin; from then on, only a single command from the host is required to turn each individual open drain output to an ON or OFF state, or to cycle a programmed frequency and duty cycle. Maximum output sink current is 25 mA per pin and 200 mA per package. Any ports not used for controlling the LEDs can be used for general purpose input/output expansion.