Features High-voltage DC/DC boost converter with integrated FET 5.5V to 22V input voltage range to support 2x, 3x and 4x Li-Ion batteries. PWM phase shift control with adaptive boost output to increase efficiency compared to conventional boost converters topologies PWM brightness control for single wire control and stand-alone use Digital Ambient light sensor interface with user-programmed ambient light to backlight brightness curve Easy-to-use EEPROM calibration for current, intensity and ambient light response setting Seven LED drivers with LED fault (short/open) detection Eight-bit LED current control Internal thermal protection and backlight safety dimming feature Two wire, SMBus/ I 2C-compatible control interface Low-input voltage detection and shutdown Minimum number of external components LLP 24-pin package, 4 x 4 x 0.8 mm Description The LP8543 is a white LED driver with integrated boost converter. It has 7 adjustable current sinks which can be controlled by SMBus or I 2C-compatible serial interface, PWM input and Ambient Light Sensor (ALS). The boost converter has adaptive output voltage control based on the LED driver voltages. This feature minimizes the power consumption by adjusting the voltage to lowest sufficient level in all conditions. Phase Shift PWM dimming offers further power saving especially when there is poor matching in the forward voltages of the LED strings. Boost voltage can also be controlled through the SMBus/I 2C. Internal EEPROM stores the data for backlight brightness and ambient light sensor calibration. Brightness can be calibrated during the backlight unit production so that all units produce the same brightness. EEPROM also stores the coefficients for the LED control equations and the default LED current value. LED current has 8–bit adjustment from 0 to 60 mA. The LP8543 has several safety and diagnostic features. Low-input voltage detection turns the chip off if the system gets stuck and battery fully discharges. Input voltage detection threshold is adjustable for different battery configurations. Thermal regulation reduces backlight brightness above a set temperature. LED fault detection reports open or LED short fault. Boost over-current fault detection protects the chip in case of over-current event. LP8543 is available in the LLP 24-pin package. Applications Medium sized (>10 inches) LCD Display Backlight LED Lighting

typ app 1

Typical Application click for larger image typ app 1	Block Diagram click for larger image LP8543 Block Diagram
Typical Performance click for larger image

Datasheets

Title		Size	Date	Other Language
	LP8543 SMBus/I2C Controlled WLED Driver for Medium Sized LCD Backlight	796 Kbytes	14-Nov-11

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Pack Size
LP8543SQ RoHS Status	LLP	Full production Lead Time: 12 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$2.30 each at 1K+ pcs	reel of 1000
LP8543SQE/NOPB RoHS Status	LLP	Full production Lead Time: 12 weeks	Distributor Region Qty DIGI-KEY Worldwide 0 FARNELL Europe and Asia 203 MOUSER Worldwide 469 NEWARK Americas 203	$2.30 each at 1K+ pcs	reel of 250
LP8543SQX/NOPB RoHS Status	LLP	Full production Lead Time: 12 weeks	Distributor Region Qty DIGI-KEY Worldwide 0	$2.30 each at 1K+ pcs	reel of 4500

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LP8543.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LP8543 is located at RoHS Status.

Part Number(s) (NSID)	Weight (milligrams)	Type	Pins	MSL Rating	Peak Reflow	RoHS Status	CAD Symbols	Models	Package Marking Format
LP8543SQ	39.849	LLP	24			Detail	N/A	N/A	NS UZXYTT L8543SQ
LP8543SQE/NOPB	39.849	LLP	24	1	260	Detail	N/A	N/A	NS UZXYTT L8543SQ
LP8543SQX/NOPB	39.849	LLP	24	1	260	Detail	N/A	N/A	NS UZXYTT L8543SQ

All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

Moisture Sensitivity Level Data for LP8543.

A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

National's certificate of product compliance for LP8543 is located at RoHS Status.

CAD Symbols and Models N/A

Models N/A