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8 Lead SOIC Package
MX841
White LED Step-Up Converter
General Description
The MX841 is a fixed frequency, constant current
source step-up DC/DC converter. The output current
is directly regulated making the MX841 ideal for
driving series connected white light emitting diodes
(LED鈥檚) in backlight applications. The MX841
powers up to 3 series white LED鈥檚 at 1.1V, and 20
series/parallel white LED鈥檚 at 5.0V.
The MX841 features a 1.0MHz switching frequency
to accommodate the use of small capacitors and a
small inductor necessary in size sensitive portable
applications. Light intensity and shutdown are
conveniently controlled by a single analog voltage.
Power efficiency and battery life are extended
through the use of a high voltage, low R
DSON
N-
channel MOSFET switch.
The MX841 is designed to operate over a
temperature range of -40擄C to +85擄C, and is
available in an SOIC-8 Package, with or without an
Exposed Pad in Tube or on Tape and Reel.
(Alternate package types available upon request).
Applications:
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White LED Display Backlighting
-
Low Voltage: Mobile Phones, PDA鈥檚,
MP3 Players, Digital Cameras
-
High Drive Current: Vehicle
Instrumentation Panels
Ordering Information
Part No.
17000-00TU
17000-00TR
17043-00TU
17043-00TR
Description
SOIC-8
Standard Tube
SOIC-8
Standard T&R
SOIC-8
Exposed Pad Tube
SOIC-8
Exposed Pad T&R
Qty
100
2500
100
2500
Functional Block Diagram
Typical Application
VDD
SW
SW
Vbattery
Vboost
osc
CTL/SLEEP
err amp/
comparator
driver
5
1
4
VDD
SW
SW
OVD
6
Analog
Gnd
band gap
+
compare
OVD
CTRL
Isense
7
CTL/
SLEEP
MX841
Isense
8
Switch
Gnd
sleep det
bias gen
Analog
GND
2
Switch
GND
3
Rsense
MX841
Drawing No. 17023
Preliminary
1
03/10/05
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