lx1992| Datasheet

Datasheet preview, take a look at Datasheets before downloading (Data Sheet is available on manufacturer site)

LX1992
TM

High Efficiency LED Driver
P RODUCTION D ATA S HEET

DESCRIPTION

KEY FEATURES

WWW . Microsemi .C OM

The LX1992 is a compact high efficiency step-up boost controller for driving white or color LEDs in backlight or frontlight systems and offers designers maximum flexibility with respect to efficiency and cost. The LX1992 features a pseudohysteretic pulse frequency modulation topology and uses an external NChannel MOSFET. Further, the LX1992 features control circuitry that is optimized for portable systems (e.g., quiescent supply current of 80uA (typ) and a shutdown current of less than 1uA). These design enhancements provide for improved performance in battery operated systems applications. The device input voltage range is from 1.6V to 6.0, allowing for a wide selection of system battery voltages and start-up operation is guaranteed at 1.6V input.

Programming the output current is readily achieved by using one external current sense resistor in series with the LEDs. In this configuration, LED current provides a feedback signal to the FB pin, maintaining constant current regardless of varying LED forward voltage (VF). Moreover, the LX1992 is capable of achieving output currents in excess of 150mA, depending on the MOSFET selected. The LX1992 has an additional feature for simple dynamic adjustment of the output current (i.e., up to 100% of the maximum programmed current). Designers can make this adjustment via an analog reference signal or a direct PWM generated signal applied to the ADJ pin and any PWM amplitude is easily accommodated with a single external resistor. The LX1992 is available in both the 8Pin MSOP, and the miniature 8-Pin MLP requiring minimal PCB area.

> 90% Efficiency 80uA Typical Quiescent Supply Current Externally Programmable Peak Inductor Current Limit For Maximum Efficiency Logic Controlled Shutdown < 1uA Shutdown Current Dynamic Output Current Adjustment Via Analog Reference Or Direct PWM Input 8-Pin MSOP Package or 8-Pin MLP APPLICATIONS/BENEFITS Pagers Wireless Phones PDAs Handheld Computers General LCD Bias Applications LED Driver Digital Camera Displays

IMPORTANT: For the most current data, consult MICROSEMI's website: http://www.microsemi.com

PRODUCT HIGHLIGHT
L1

V BAT = 1.6V to 6.0V

47 u H 1206 C ase Size

C1 4.7 u F

DR V IN SR C

O FF

SHD N

LX1992
FB ADJ GND CS R CS 4 k

V F = 3.6V typ. I LED = 20mA to 0mA

R SET
15

LX1992 LX1992

TA ( C) 0 to 70
Copyright 2000 Rev. 1.1b, 2005-03-03

PACKAGE ORDER INFO Plastic MLP Plastic MSOP LM 8-Pin DU 8-Pin
RoHS Compliant / Pb-free Transition DC: 0452 RoHS Compliant / Pb-free Transition DC: 0432

LX1992CLM

LX1992CDU

Note: Available in Tape & Reel. Append the letters "TR" to the part number. (i.e. LX1992CDU-TR)

Microsemi
Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1