National LP3944 Data Sheet Manual

November

LP /W hite/B lue 8-LE Fun Light river

LP3944 RGB/White/Blue 8-LED Fun Light Driver General Description Features

LP3944 is an integrated device capable of independently Internal power-on reset driving LEDs. This device also contains an internal preci- Active low reset

sion oscillator that provides all the necessary timing required Internal precision oscillator for driving each LED. Two prescaler registers along with two

Variable dim rates (from 6.25 ms to 1.6s;

PWM registers provide versatile duty cycle control. The

Hz–0.625 Hz)

LP3944 contains the ability to dim LEDs in SMBUS/I2C applications where it is required to cut down on bus traffic.

Key Specifications

Traditionally, to dim LEDs using serial shift register such as

LED driver (multiple programmable states on, off,

74LS594/5 would require large amount of traffic to be on

input, and dimming at specified rate)

the serial bus. LP3944 instead requires only the setup of the

Open drain outputs capable of driving up to m A per

frequency and duty cycle for each output pin. From then on,

only single command from the host is required to turn each individual open drain output ON, OFF, or to cycle pro-

grammed frequency and duty cycle. Maximum output sink Applications

current is m A per pin and m A per package. Any ports Customized flashing LED lights for cellular phones not used for controlling the LEDs can be used for general

Portable Applications

purpose input/output expansion.

Digital Cameras Indicator Lamps General purpose I/O expander Toys

Typical Application Circuit

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