CAT4238 Datasheet, PDF (1/12 Pages) Catalyst Semiconductor – High Efficiency 10 LED Boost Converter

CAT4238
High Efficiency 10 LED
Boost Converter
Description
The CAT4238 is a DC/DC step−up converter that delivers an
accurate constant current ideal for driving LEDs. Operation at a fixed
switching frequency of 1 MHz allows the device to be used with small
value external ceramic capacitors and inductor. LEDs connected in
series are driven with a regulated current set by the external resistor
R₁. LED currents up to 40 mA can be supported over a wide range of
input supply voltages up to 5.5 V, making the device ideal for
battery−powered applications. The CAT4238 high−voltage output
stage is perfect for driving mid−size and large panel displays
containing up to ten white LEDs in series.
LED dimming can be done by using a DC voltage, a logic signal, or
a pulse width modulation (PWM) signal. The shutdown input pin
allows the device to be placed in power−down mode with “zero”
quiescent current.
In addition to thermal protection and overload current limiting, the
device also enters a very low power operating mode during “Open
LED” fault conditions. The device is housed in a low profile (1 mm
max height) 5−lead thin SOT23 package for space critical
applications.
Features
• Drives High Voltage LED Strings (38 V)
• Up to 87% Efficiency
• Low Quiescent Ground Current 0.6 mA
• Adjustable Output Current
• 1 MHz Fixed Frequency Low Noise Operation
• Soft Start “In−rush” Current Limiting
• Shutdown Current Less than 1 mA
• Open LED Overvoltage Protection
• Automatic Shutdown at 1.9 V (UVLO)
• Thermal Overload Protection
• Thin SOT23 5−lead (1 mm Max Height)
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Applications
• GPS Navigation Systems
• Portable Media Players
• Handheld Devices, Digital Cameras
• Portable Game Machines
http://onsemi.com
5
1
TSOT−23
TD SUFFIX
CASE 419AE
PIN CONNECTIONS
1
SW
VIN
GND
FB
SHDN
(Top View)
MARKING DIAGRAM
MUYM
MU = Specific Device Code
Y = Production Year (Last Digit)
M = Production Month (1−9, A, B, C)
ORDERING INFORMATION
Device
CAT4238TD−GT3
Package
TSOT−23
(Pb−Free)
Green*
Shipping
3,000/
Tape & Reel
* Lead Finish NiPdAu
© Semiconductor Components Industries, LLC, 2010
1
February, 2010 − Rev. 4
Publication Order Number:
CAT4238/D