CAT4240 Datasheet, PDF (1/12 Pages) Catalyst Semiconductor – 6 Watt Boost LED Driver

CAT4240
6 Watt Boost LED Driver
Description
The CAT4240 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. The
CAT4240 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.
http://onsemi.com
5
1
TSOT−23
TD SUFFIX
CASE 419AE
PIN CONNECTIONS
1
SW
VIN
Features
• Switch Current Limit 750 mA
• Drives High Voltage LED Strings (38 V)
• Up to 94% Efficiency
• Low Quiescent Ground Current 0.6 mA
• 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
GND
FB
(Top View)
SHDN
MARKING DIAGRAM
TGYM
TG = Specific Device Code
Y = Production Year (Last Digit)
M = Production Month (1−9, A, B, C)
ORDERING INFORMATION
Device
CAT4240TD−GT3
Package
TSOT−23
(Pb−Free)
Green*
Shipping
3,000/
Tape & Reel
* NiPdAu Plated Finish
V_L
L1
D1
VOUT
8 V to _C1
16 V
VIN
5V
C3
47 mH
C2
4.7 mF/16 V
1 μF/50 V
SW
VIN
CAT4240
1 μF
SHDN
GND
(300 mV) ^R2
FB
1 kW
L1: Sumida CDRH6D28−470
D1: Central CMSH1−40 (rated 40 V)
300 mA
R1
1W
Figure 1. Typical Application Circuit
© Semiconductor Components Industries, LLC, 2010
1
February, 2010 − Rev. 3
Publication Order Number:
CAT4240/D