CAT4240
6 Watt Boost LED Driver
FEATURES
Switch Current Limit 750mA
Drives High Voltage LED strings (38V)
Up to 94% Efficiency
Low Quiescent Ground Current 0.6mA
1MHz Fixed Frequency Low noise Operation
Soft start “in-rush” current limiting
Shutdown current less than 1μA
Open LED Overvoltage Protection
Automatic Shutdown at 1.9V (UVLO)
Thermal overload protection
Thin SOT23 5-Lead (1mm max height)
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 1MHz 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 (1mm max height) 5-lead
thin SOT23 package for space critical applications.
APPLICATIONS
GPS Navigation Systems
Portable Media Players
Handheld Devices, Digital Cameras
ORDERING INFORMATION
Part Number
CAT4240TD-GT3
* NiPdAu Plated Finish
Package
TSOT23-5
Green*
Quantity Package
per Reel Marking
3000
TG
For Ordering Information details, see page 13.
Pin Configuration
TSOT23 5-Lead
(1mm max height)
SW
GND
FB
1
2
3
4
SHDN
5
VIN
Typical Application Circuit
V
L
8V to
16V
VIN
5V
C1
L1
47µH
4.7µF/16V
VIN
SW
D1
C2
1µF/50V
VOUT
C3
1µF
CAT4240
SHDN
GND
FB
(300mV) R2
1kΩ
R1
1Ω
300mA
Top View
L1: Sumida CDRH6D28-470
D1: Central CMSH1-40 (rated 40V)
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5026 Rev. C
CATALYST [ CATALYST SEMICONDUCTOR ]
