SC4539ULTRT Semtech, SC4539ULTRT Datasheet

no-image

SC4539ULTRT

Manufacturer Part Number
SC4539ULTRT
Description
TVS
Manufacturer
Semtech
Datasheets

Specifications of SC4539ULTRT

Lead Free Status / RoHS Status
Lead free / RoHS Compliant
POWER MANAGEMENT
Features
Applications
Typical Application Circuit
September 5, 2007
Input voltage range — 2.8V to 5.5V
Current-mode PWM control — 800kHz
Programmable LED current up to 30mA
Soft-start to reduce in-rush current
PWM dimming — 100Hz to 50kHz
PWM dimming at ISET — Analog and fi ltered
Over-voltage protection — 25V (max.)
Under-voltage lockout (UVLO)
Thermal shutdown
Shutdown current — <1μA
Ultra-thin package — 2mm x 2mm x 0.6mm
Lead-free package, WEEE and RoHS compliant
White LED Display Backlight Driver
Smartphones and PDAs
Cellular Handsets
MP3 and Portable Media Players
DSC, GPS, Satellite Radio, Game Players
PWM dimming
Enable and
2.8 to
5.5V
C
COMP
C
IN
R
COMP
R
ISET
L1
IN
EN
ISET
COMP
SC4539
GND
LX
Description
The SC4539 is designed to regulate current for a series
chain of white LEDs in LCD backlighting applications
where small size and high effi ciency are priorities. This
device integrates an 800kHz current-mode PWM boost
converter and a 30mA programmable low dropout current
sink regulator.
An external resistor sets the LED current up to 30mA.
PWM dimming (100Hz to 50kHz) may be applied directly
to the enable (EN) pin, or dimming can be controlled by
applying an analog signal to the ISET circuit. The boost
circuit can output up to 22V (guaranteed) to drive up to 6
LEDs in series. The current regulator protects against
shorts between the BL and OUT pins and also eliminates
backlight glow during shutdown when using LEDs with
high leakage. Under-voltage lockout and thermal shut-
down provide additional protection. A small external
capacitor and series resistor control soft-start and loop
compensation. Over-voltage detection protects the
SC4539 if the LED pin is fl oating or shorted to ground.
The SC4539 is available in an MLPD-8 pin 2mm x 2mm x
0.6mm package, with a rated temperature range of -40°C
to +85°C.
D
OUT
High Effi ciency Boost Converter
BL
C
OUT
for up to 6 LEDS
SC4539
1

Related parts for SC4539ULTRT

Related keywords