CAT4139 Datasheet, PDF (1/13 Pages) Catalyst Semiconductor – 22V High Current Boost White LED Driver

22V High Current Boost White LED Driver
CAT4139
FEATURES
„ Switch Current Limit 750mA
„ Drives LED strings up to 22V
„ 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
„ TSOT-23 5-Lead (1mm max height)
APPLICATIONS
„ GPS Navigation Systems
„ Portable Media Players
„ Handheld Devices
ORDERING INFORMATION
Part Number
Package
Quantity Package
per Reel Marking
CAT4139TD-GT3 TSOT23-5* 3000
TP
* NiPdAu Plated Finish, RoHS compliant
For Ordering Information details, see page 12.
PIN CONFIGURATION
TSOT-23 5-Lead
SW 1
GND 2
FB 3
5 VIN
4 SHDN
Top View
DESCRIPTION
The CAT4139 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 CAT4139
is ideal for driving parallel strings of up to five white
LEDs in series or up to 22V.
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 TSOT-23 package for space critical
applications.
TYPICAL APPLICATION CIRCUIT
9 strings at
V_IN
L
D
V_OUT 20mA
5V
C1
22µH
C2
4.7µF
OFF ON
SW 1µF
VIN
35V
CAT4139
R2
SHDN FB
(300mV)
GND
1kΩ
I_OUT
180mA
R1
1.62Ω
L: Sumida CDRH6D28-220
D: Central CMSH1-40 (rated 40V)
© Catalyst Semiconductor, Inc.
1
Characteristics subject to change without notice
Doc. No. MD-5032 Rev. A