LP3944_14 Datasheet, PDF (1/17 Pages) Texas Instruments – RGB/White/Blue 8-LED Fun Light Driver

LP3944
www.ti.com
SNVS264 – MAY 2004
LP3944 RGB/White/Blue 8-LED Fun Light Driver
Check for Samples: LP3944
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
KEY SPECIFICATIONS
• 8 LED Driver (Multiple Programmable
States—On, Off, Input, and Dimming at a
Specified Rate)
• 8 Open Drain Outputs Capable of Driving up to
25 mA per LED
DESCRIPTION
LP3944 is an integrated device capable of
independently driving 8 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
LP3944 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. LP3944 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.
Typical Application Circuit
+5V
5V
SMBUS
/I²C
RGB
SDA
SCL
PORTx.D
Cell Phone Baseband
Controller/PController
V_DD
SDA
SCL
RESET
A2
A1
A0
LED7
LED6
LED5
LED4
LED3
LED2
LED1
LED0
GND
+5V
Blue LEDs
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
2
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