LP3943 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – RGB/White/Blue 16-LED Fun Light Driver

LP3943
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SNVS256A – MAY 2004 – REVISED MAY 2004
LP3943 RGB/White/Blue 16-LED Fun Light Driver
Check for Samples: LP3943
FEATURES
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•2 Internal power-on reset
• Active low reset
• Internal precision oscillator
• Variable dim rates (from 6.25 ms to 1.6s; 160
Hz–0.625 Hz)
APPLICATIONS
• Customized flashing LED lights for cellular
phones
• Portable Applications
• Digital Cameras
• Indicator Lamps
• General purpose I/O expander
• Toys
DESCRIPTION
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, to dim LEDs using a serial shift register such as 74LS594/5 would require a large amount of traffic
to be on the serial bus. 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 ON,
OFF, 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.
Table 1. Key Specifications
16 LED driver (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
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004, Texas Instruments Incorporated