LX1992
High Efficiency LED Driver
L I N F I N I T Y D I V I S I O N
PRODUCTION
KEY FEATURES
DESCRIPTION
ꢀ > 90% Efficiency
The LX1992 is a compact high
Programming the output current is
ꢀ 80µA Typical Quiescent Supply
Current
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
with respect to efficiency and cost. the FB pin, maintaining constant current
ꢀ Externally Programmable Peak
Inductor Current Limit For
Maximum Efficiency
ꢀ Logic Controlled Shutdown
ꢀ < 1µA Shutdown Current
ꢀ Dynamic Output Current
Adjustment Via Analog
Reference Or Direct PWM Input
ꢀ 8-Pin MSOP Package or 8-Pin
MLP
The LX1992 features
a pseudo- regardless of varying LED forward
hysteretic pulse frequency modulation voltage (VF). 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
APPLICATIONS/BENEFITS
than
1µA).
These
design maximum
programmed
current).
ꢀ Pagers
enhancements provide for improved Designers can make this adjustment via
performance in battery operated an analog reference signal or a direct
ꢀ Wireless Phones
ꢀ PDAs
systems applications.
PWM generated signal applied to the
ꢀ Handheld Computers
ꢀ General LCD Bias Applications
ꢀ LED Driver
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.
ꢀ Digital Camera Displays
and
start-up
operation
is
The LX1992 is available in both the 8-
Pin MSOP, and the miniature 8-Pin MLP
requiring minimal PCB area.
guaranteed at 1.6V input.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
L1
VBAT = 1.6V to 6.0V
47µH
1206 Case Size
C1
4.7µF
DRV
IN
SRC
SHDN
ON OFF
LX1992
FB
ADJ
CS
GND
RCS
4kΩ
VF = 3.6V typ.
ILED = 20mA to 0mA
RSET
15Ω
PACKAGE ORDER INFO
Plastic MLP
8-Pin
LX1992CLM
Plastic MSOP
DU
8-Pin
TA (°C)
0 to 70
LM
LX1992CDU
Note: Available in Tape & Reel.
Append the letter “T” to the part number. (i.e. LX1992CDUT)
Copyright 2000
Microsemi
Page 1
Rev. 1.1, 2002-11-21
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570