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參數資料
| 型號： | SC4540ULTRT |
| 元件分類： | 穩壓器 |
| 英文描述： | SWITCHING REGULATOR, 920 kHz SWITCHING FREQ-MAX, DSO8 |
| 封裝： | 2 X 2 MM, ROHS COMPLIANT, MLPD-8 |
| 文件頁數： | 1/15頁 |
| 文件大小： | 281K |
| 代理商： | SC4540ULTRT |
2008 Semtech Corporation
1
POWER MANAGEMENT
1
Typical Application Circuit
Applications
DSLR, DSC, and Video Cameras
Portable media players
Set-top boxes
Personal navigation devices
SC4540
High Efficiency Boost Converter
for up to 10 LEDs
Features
Input voltage range — 4.5V to 12V
Programmable LED current up to 30mA
Current-mode PWM control — 800kHz
Soft-start to reduce in-rush current
PWM dimming — 100Hz to 50kHz
PWM dimming at ISET — analog and filtered
Over-voltage protection — 38V (minimum)
Under-voltage lockout (UVLO)
Thermal shutdown
Shutdown current — <0.1μA (typical)
Ultra-thin package — 2 x 2 x 0.6 (mm)
Lead-free package, WEEE and RoHS compliant
Description
The SC4540 is designed to regulate current for a series
string of white LEDs in LCD backlighting applications
where small size and high efficiency are priorities. This
device integrates an 800kHz current-mode PWM boost
converter and a 30mA programmable low dropout current
sink regulator. The wide input voltage range of the SC4540
makes it ideal for use with dual-cell Li-ion powered
applications.
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 38V (guaranteed) to drive up to 10
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
SC4540 if the BL pin is floating or shorted to ground.
The SC4540 is available in an MLPD-8 pin 2 x 2 x 0.6 (mm)
package, with a rated temperature range of -40°C to
+85°C.
OU T
LX
BL
CIN
4.5 to 12V
IN
EN
ISET
GN D
COM P
E nable and
PW M
dim m ing
L1
D
C OUT
SC 4540
1 μF
56μH
2.2μF
RISET
CCOM P
1.27kΩ
47n F
RCOM P
July 18, 2008
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相關代理商/技術參數 |
參數描述 |
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| SC4541SKTRT | 功能描述:IC LED DRVR BACKLIGHT SOT23-6 RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅動器 系列:- 標準包裝:60 系列:- 恒定電流:- 恒定電壓:- 拓撲:線性（LDO），PWM，升壓（升壓） 輸出數:8 內部驅動器:是 類型 - 主要:背光 類型 - 次要:RGB，白色 LED 頻率:500kHz ~ 1.5MHz 電源電壓:4.75 V ~ 26 V 輸出電壓:45V 安裝類型:* 封裝/外殼:* 供應商設備封裝:* 包裝:* 工作溫度:-40°C ~ 85°C |
| SC4541ULTRT | 制造商:Semtech Corporation 功能描述:SINGLE WIRE BACKLIGHT DRIVER |
| SC454MLTRT | 制造商:Semtech Corporation 功能描述:PWM Controller 32-Pin MLP T/R 制造商:Semtech Corporation 功能描述:SINGLE PHASE PWR SUPPLY CONTLR |
| SC4560 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:相機閃光燈控制IC |
| SC457 | 制造商:SEMTECH 制造商全稱:Semtech Corporation 功能描述:Single-Phase Single Chip Vcore Power Supply |
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