LT1947 Adjustable Output TFT-LCD Triple Switching Regulator DESCRIPTIO FEATURES Complete Solution Under 1.2mm The LT 1947 is a highly integrated multiple output DC/DC Develops Three Outputs from a 3.3V or 5V Supply converter designed for use in TFT-LCD panels. The device Externally Programmable V Delay contains two independent switching regulators. The main ON Fixed Frequency Low Noise Outputs regulator has an adjustable output voltage with an internal All Ceramic Capacitors 1.1A switch that can generate a boosted voltage as high as 3MHz Switching Frequency 30V. The second regulators output is also adjustable up Fast Transient Response to 30V and can deliver 10mA for positive bias. A simple Few External Components Required level-shift charge pump off the main switch node gener- 2.7V to 8V Input Range ates the negative bias voltage. An external capacitor sets Adjustable AV and V Voltages the delay time from AV s final value to the rising edge at DD ON DD Tiny 10-Lead MSOP and Thermally Enhanced the V pin. The 3MHz switching frequency allows the use ON 10-Lead MSOP Packages of tiny low profile chip inductors and capacitors through- U out, providing a low noise, low cost total solution with all APPLICATIO S components under 1.2mm in height. The device operates from an input range of 2.7V to 8V and is available in TFT-LCD Notebook Display Panels 10-lead MSOP and thermally enhanced 10-lead MSOP TFT-LCD Desktop Monitor Display Panels packages. Digital Cameras , LTC and LT are registered trademarks of Linear Technology Corporation. Handheld Computers All other trademarks are the property of their respective owners. TYPICAL APPLICATIO D3 D4 V OFF 8V 10mA C4 0.68F C6 L1 CERAMIC 0.68F 3.3H AV DD V IN 8V 200mA D1 Start-Up Waveforms L2 R1 4.7H V SW1 C2 IN 53.6k V SHDN 3.3F SW2 FB1 5V/DIV CERAMIC C1 D2 2 2.2F V ON CERAMIC R2 V LT1947 20V/DIV O2 10k R3 182k V ON C3 FB2 V 24V ON 220nF AV DD 10mA R4 SHDN C GND 10V/DIV T 10k SHUTDOWN C5 V OFF 10nF 10V/DIV C1: TAIYO YUDEN LMK316BJ225MD D1: MBRM120LT3 2ms/DIV 1947 TA01.tif 1947 F01 C2: TAIYO YUDEN LMK325BJ335MD 2 D2: CMDSH-3 C3: AVX 0.22F 25V X7R D3, D4: BAT54S DUAL DIODE C4, C6: TAIYO YUDEN LMK107BJ684MA L1: SUMIDA CLQ4D103R3 L2: TAIYO YUDEN LB2012B4R7M Figure 1. 3.3V Powered TFT-LCD Bias Generator 1947fa 1 U ULT1947 ABSOLUTE AXI U RATI GS (Note 1) FB1, FB2 .................................................................... 3V V Voltage ................................................................ 8V IN SHDN......................................................................... 8V C Voltage.................................................................. 6V T Operating Temperature Range (Note 2) .. 40C to 85C SW1, SW2 Voltage .................................................. 36V Lead Temperature (Soldering, 10 sec).................. 300C V , V Voltage ..................................................... 30V ON O2 UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART NUMBER NUMBER TOP VIEW TOP VIEW FB1 1 10 V FB1 1 10 V ON ON LT1947EMSE FB2 2 9 V LT1947EMS FB2 2 9 V 02 O2 C 3 8 SHDN C 3 8 T 11 SHDN T SW1 4 7 SW2 SW1 4 7 SW2 GND 5 6 V GND 5 6 V IN IN MSE PACKAGE MS PACKAGE 10-LEAD PLASTIC MSOP MSE PART MARKING 10-LEAD PLASTIC MSOP MS PART MARKING EXPOSED PAD (PIN 11) IS GND T = 125C, = 120C/W JMAX JA MUST BE SOLDERED TO PCB LTBQW LTUE T = 125C, = 40C/W JMAX JA Order Options Tape and Reel: Add TR, Lead Free: Add PBF, Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: