LX1992 Datasheet, PDF (1/11 Pages) Microsemi Corporation – High Efficiency LED Driver

LX1992
TM
®
High Efficiency LED Driver
PRODUCTION DATA SHEET
DESCRIPTION
The LX1992 is a compact high Programming the output current is
efficiency step-up boost controller for readily achieved by using one external
driving white or color LEDs in current sense resistor in series with the
backlight or frontlight systems and LEDs. In this configuration, LED
offers designers maximum flexibility current provides a feedback signal to the
with respect to efficiency and cost. FB pin, maintaining constant current
The LX1992 features a pseudo- regardless of varying LED forward
hysteretic pulse frequency modulation voltage (V_F). Moreover, the LX1992 is
topology and uses an external N- capable of achieving output currents in
Channel MOSFET. Further, the excess of 150mA, depending on the
LX1992 features control circuitry that MOSFET selected.
is optimized for portable systems (e.g., The LX1992 has an additional feature
quiescent supply current of 80µA for simple dynamic adjustment of the
(typ) and a shutdown current of less output current (i.e., up to 100% of the
than 1µA).
These design maximum programmed current).
enhancements provide for improved Designers can make this adjustment via
performance in battery operated an analog reference signal or a direct
systems applications.
PWM generated signal applied to the
The device input voltage range is ADJ pin and any PWM amplitude is
from 1.6V to 6.0, allowing for a wide easily accommodated with a single
selection of system battery voltages external resistor.
and start-up operation is The LX1992 is available in both the 8-
guaranteed at 1.6V input.
Pin MSOP, and the miniature 8-Pin MLP
requiring minimal PCB area.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
KEY FEATURES
ƒ > 90% Efficiency
ƒ 80µA Typical Quiescent Supply
Current
ƒ Externally Programmable Peak
Inductor Current Limit For
Maximum Efficiency
ƒ Logic Controlled Shutdown
ƒ < 1µA Shutdown Current
ƒ Dynamic Output Current
Adjustment Via Analog
Reference Or Direct PWM Input
ƒ 8-Pin MSOP Package or 8-Pin
MLP
APPLICATIONS/BENEFITS
ƒ Pagers
ƒ Wireless Phones
ƒ PDAs
ƒ Handheld Computers
ƒ General LCD Bias Applications
ƒ LED Driver
ƒ Digital Camera Displays
V_BAT = 1.6V to 6.0V
PRODUCT HIGHLIGHT
L₁
47µ H
1206 Case Size
ON OFF
V_F = 3.6V typ.
I_LED = 20mA to 0mA
IN
SHDN
DRV
SRC
LX1992
FB
ADJ
CS
GND
R
CS
4 kΩ
C₁
4.7µ F
R_SET
15Ω
Copyright © 2000
Rev. 1.1b, 2005-03-03
T_A (°C)
0 to 70
PACKAGE ORDER INFO
Plastic MLP
Plastic MSOP
LM _8-Pin
DU _8-Pin
RoHS Compliant / Pb-free RoHS Compliant / Pb-free
Transition DC: 0452
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: [phone]
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