LED Driver. CAT4240 Datasheet

CAT4240 Driver. Datasheet pdf. Equivalent

Part CAT4240
Description 6 Watt Boost LED Driver
Feature www.DataSheet4U.com CAT4240 6 Watt Boost LED Driver FEATURES „ „ „ „ „ „ „ „ „ „ „ Switch Current .
Manufacture Catalyst Semiconductor
Datasheet
Download CAT4240 Datasheet



CAT4240
www.DataSheet4U.com
6 Watt Boost LED Driver
CAT4240
FEATURES
„ Switch Current Limit 750mA
„ Drives High Voltage LED strings (38V)
„ Up to 87% 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)
APPLICATIONS
„ GPS Navigation Systems
„ Portable Media Players
„ Handheld Devices, Digital Cameras
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.
ORDERING INFORMATION
Part Number
Package
Quantity Package
per Reel Marking
CAT4240TD-GT3
TSOT23-5
Green*
3000
TG
* NiPdAu Plated Finish
For Ordering Information details, see page 13.
Pin Configuration
5-Lead Thin SOT23
(1mm max height)
SW 1
GND 2
FB 3
5 VIN
4 SHDN
Typical Application Circuit
VL
8V to
16V
C1
VIN
5V C3
1µF
L1 D1
47µH
4.7µF/16V
SW
VIN
C2
1µF/50V
VOUT
CAT4240
SHDN
FB (300mV) R2
GND
1k
300mA
R1
1
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
L1: Sumida CDRH6D28-470
D1: Central CMSH1-40 (rated 40V)
1
Doc. No. MD-5026 Rev. A



CAT4240
www.DataSheet4U.com
CAT4240
ABSOLUTE MAXIMUM RATINGS
Parameters
VIN, FB voltage
S¯¯H¯D¯N¯ voltage
SW voltage
Storage Temperature Range
Junction Temperature Range
Lead Temperature
Ratings
-0.3 to +7
-0.3 to +7
-0.3 to 60
-65 to +160
-40 to +125
300
Units
V
V
V
ºC
ºC
ºC
RECOMMENDED OPERATING CONDITIONS
Typical application circuit with external components are shown on page 1.
Parameters
VIN
SW pin voltage
Ambient Temperature Range (1)
Range
up to 5.5
0 to 38
-40 to +85
Units
V
V
ºC
DC ELECTRICAL CHARACTERISTICS
VIN = 3.6V, ambient temperature of 25ºC (over recommended operating conditions unless specified otherwise).
Symbol Parameter
IQ Operating Current
ISD Shutdown Current
VFB FB Pin Voltage
IFB FB pin input leakage
ILED Programmed LED Current
VIH S¯¯H¯D¯N¯ Logic High
VIL S¯¯H¯D¯N¯ Logic Low
FSW Switching Frequency
DC Maximum Duty Cycle
ILIM Switch Current Limit
RSW Switch “On” Resistance
ILEAK Switch Leakage Current
Thermal Shutdown
Test Conditions
VFB = 0.2V
VFB = 0.4V (not switching)
VS¯¯H¯D¯N¯ = 0V
6 LEDs with ILED = 75mA
R1 = 10
R1 = 5
Enable Threshold Level
Shutdown Threshold Level
VIN = 3V
VIN = 3.6V
VIN = 5V
ISW = 100mA
Switch Off, VSW = 30V
Min
285
28.5
0.4
0.8
600
750
Typ
0.6
0.1
0.1
300
30
60
0.8
0.7
1.0
92
1.0
2
150
Max
1.5
0.6
1
315
1
31.5
1.5
1.3
2.0
5
Units
mA
µA
mV
µA
mA
V
V
MHz
%
mA
µA
ºC
Thermal Hysteresis
20 ºC
VUVLO
Undervoltage Lockout (UVLO)
Threshold
1.9 V
VOV-SW Overvoltage Detection Threshold
VOCL Output Voltage Clamp
“Open LED”
40 V
42 V
Note:
(1) Thin SOT23-5 package thermal resistance θJA = 135°C/W when mounted on board over a ground plane.
Doc. No. MD-5026 Rev. A
2 © 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice







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