LT1947 Datasheet | Linear Technology

LT1947 Adjustable Output TFT-LCD Triple Switching Regulator Features s s s s s s s s s s s DESCRIPTIO plete Solution Under 1.2mm Develops Three Outputs from a 3.3V or 5V Supply Externally Programmable VON Delay Fixed Frequency Low Noise Outputs All Ceramic Capacitors 3MHz Switching Frequency Fast Transient Response Few External ponents Required 2.7V to 8V Input Range Adjustable AVDD and VON Voltages Tiny 10-Lead MSOP Package U APPLICATIO S s s s s TFT-LCD Notebook Display Panels TFT-LCD Desktop Monitor Display Panels Digital Cameras Handheld puters The LT®1947 is a highly integrated multiple output DC/DC converter designed for use in TFT-LCD panels. The device contains two independent switching regulators. The main regulator has an adjustable output voltage with an internal 1.1A switch that can generate a boosted voltage as high as 30V. The second regulator’s output is also adjustable up to 30V and can deliver 10m A for positive bias. A simple level-shift charge pump off the main switch node generates the negative bias voltage. An external capacitor sets the delay time from AVDD’s final value to the rising edge at the VON pin. The 3MHz switching frequency allows the use of tiny low profile chip inductors and capacitors throughout, providing a low noise, low cost total solution with all ponents under 1.2mm in height. The device operates from an input range of 2.7V to 8V and is available in a 10-lead MSOP package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO D3 D4 L1 3.3µH VIN L2 4.7µH C1 2.2µF CERAMIC C6 0.68µF D1 VIN SW2 SW1 FB1 C4 0.68µF CERAMIC AVDD 8V 200m A R1 53.6k C2 3.3µF CERAMIC ×2 VSHDN 5V/DIV VON 20V/DIV VOFF - 8V 10m A D2 VO2 C3 220n F R3 182k FB2 R4 10k SHDN CT C5 10n F D1: MBRM120LT3 D2: CMDSH-3 D3, D4: BAT54S DUAL DIODE L1: SUMIDA CLQ4D103R3 L2: TAIYO YUDEN LB2012B4R7M VON GND LT1947 R2 10k VON 24V 10m A AVDD 10V/DIV SHUTDOWN VOFF 10V/DIV 1947 F01 C1: TAIYO YUDEN LMK316BJ225MD C2:...