QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 697 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATOR FOR 5V INPUT TFT-LCD PANELS LT1943 DESCRIPTION Demonstration Circuit 697 is a quad output power supply intended for use in large TFT-LCD panels. The circuit features the LT1943 high current quad-output switching regulator and generates a 3.3V logic supply along with the triple output supply required for the TFT-LCD panels. With an input voltage range of 4.5V to 8V, a step down regulator provides 3.3V VLOGIC with up to 1.5A current; a high power boost converter, a lower power boost converter and an inverting converter provide three independent output voltages AVDD, VON and VOFF required by the LCD panels. An internal high side PNP provides delayed turn on of the VON signal. All four switchers are synchronized to the internal 1.2MHz clock, allowing the use of low profile inductors and ceramic capacitors. They all have soft-start to limit inrush current. Long wires run from input sources (such as wall adaptors) can cause large voltage spikes during initial plug-in. C17 is installed on DC697 to damp the possible voltage spikes. C17 is not required for applications where input source is close to the regulator. Please refer to Application Note 88 for details. Design files for this circuit board are available. Call the LTC factory. LT is a trademark of Linear Technology Corporation Table 1. Performance Summary (TA = 25C unless otherwise noted) PARAMETER CONDITION VALUE Minimum Input Voltage -40C to 85C 4.5V Maximum Input Voltage -40C to 85C 8V Output Voltage VLOGIC VIN = 4.5V to 8V, IOUT = 0A to 1.5A 3.3V 3% Maximum Output Current at VLOGIC VIN = 4.5V to 8V 1.5A Typical Output Ripple VLOGIC VIN = 5V, load at VLOGIC = 1.5A (20MHz BW) 19mVP-P Typical Output Ripple AVDD VIN = 5V, load at AVDD = 500mA (20MHz BW) 33mVP-P Typical Switching Frequency 1.2MHz Logic Low Voltage-Off, -40C to 85C 0.4V MAX Logic High Voltage-On 2.4V MIN On/Off Control QUICK START PROCEDURE Demonstration circuit 697 is easy to set up to evaluate the performance of the LT1943. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the input or one of the outputs and GND ter- minals. See Figure 2 for proper scope probe technique. 1. With power off, connect the input power supply to Vin and GND. 2. Set the input between 4.5V to 8V. Turn on the power at the input. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 697 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATOR FOR 5V INPUT TFT-LCD PANELS 3. Check for the proper output voltages. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 4. Once the proper output voltages are established, adjust the loads within the operating range and ob- serve the output voltage regulation, ripple voltage, efficiency and other parameters. NOTE: If more than 20mA is needed at VON, connect L3 to a higher input, such as AVDD. Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2 4 3 Vin 4.5V-8V D Voff -10V@50mA E2 C6 2.2uF 10V R3 80.6K C7 L4 ZHCS400 0.47uF 16V 10uH 68uF 16V L2 D3 ZHCS400 16 C SW3 PGOOD L1 5 23 PGOOD E4 C3 0.22uF 10V 25 VON 26 E3 24 E6 R9 232K 13 SW1 4.7uH 14 SW1 R2 16.5K C2 22uF R1 10.0K CT C9 0.047uF 12 BOOST 4 FB1 D1 B230A C20 100pF R10 7.5K FB3 6 GND 1 GND 20 SGND 11 VC1 VC2 VC3 VC4 2 3 9 10 C21 C11 100pF 2700pF GND C25 1uF 16V C8 10uF 16V R6 95.3K 22 BIAS CMDSH-3 GND D C 17 SS-234 D2 C26 1uF 10V AVdd 13V@500mA R5 10.0K 18 RUN-SS 0.015uF B 27 8 FB4 C4 Vlogic 3.3V@1.5A E7 SW2 SW2 28 0.015uF E5 E3 R15 100K FB2 C5 3 21 VIN VIN R4 10.0K RUN-SS 2 B240A L3 6.8uH U1 LT1943EFE 15 19 SW4 Q1 Si2343DS D5 4.7uH C1 10uF 10V 7 NFB4 C24 10pF 1 + C17 E1 D6 2 1 5 R11 4.7K R12 30K C12 4700pF C13 1500pF C22 R13 13K 100pF C14 Von 30V@20mA C15 0.47uF 35V C10 2.2uF 35V R8 10.0K B C23 100pF 2200pF E9 E8 GND E10 CUSTOMER NOTICE GND E11 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 CONTRACT NO. APPROVALS DRAWN June Wu DATE 7/23/03 CHECKED TECHNOLOGY TITLE APPROVED ENGINEER Dongyan Zhou 7/23/03 DESIGNER 2 A LT1943EFE, High Current Quad Output Switching Regulator For 5V Input TFT-LCD Panels SIZE CAGE CODE SCALE: Tuesday, November 18, 2003 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 FILENAME: DWG NO REV A DC697A SHEET 1 1 OF 1 Bill Of Material Demo Bd. #697A Linear Technology Corporation LT1943EFE 6/20/2005 Item Qty Reference 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 4 1 1 1 1 1 2 1 1 11 1 1 1 1 1 1 4 1 1 C1 C8 C2 C3 C5,C4 C6 C7 C9 C10 C11 C14 C12 C13 C15 C17 C20-C23 C24 C25 C26 D1 D2 D3,D6 D5 Q1 E1-E11 L1 L2 L4 L3 R10 R11 R1,R5,R8,R4 R12 R13 Part Description CAP., X7R, 10uF, 10V, 20% 1210 CAP., X5R, 10uF, 16V, 20% 1210 CAP., X5R, 22uF, 6.3V, 20% 1206 CAP., X7R, 0.22uF, 10V, 20% 0603 CAP., X7R, 0.015uF, 16V, 20% 0402 CAP., X7R, 2.2uF, 10V, 10% 0805 CAP., X5R, 0.47uF, 16V, 20% 0603 CAP., X5R, 0.047uF, 16V, 10% 0402 CAP., X5R, 2.2uF, 35V, 20% 1210 CAP., X7R, 2700pF, 50V, 20%, 0402 CAP., X7R, 2200pF, 50V, 20% 0402 CAP., X7R, 4700pF, 50V, 20% 0402 CAP., X7R, 1500pF, 50V, 20% 0402 CAP., X5R, 0.47uF, 35V, 20% 0805 CAP., TANT, 68uF, 16V, 20% 6032 CAP., X7R, 100pF, 50V, 20% 0402 CAP., NPO, 10pF, 50V, 10% 0402 CAP., X5R, 1.0uF 16V, 20% 0805 CAP., X7R, 1.0uF 10V, 20% 0805 Schottky Barrier REC., B230A SMA Schottky Diode, CMDSH-3 SOD-323 Schottky Barries Dio., ZHCS400, SOD-323 Schottky Barrier REC., B240A SMA P-Mosfet, Si2343DS, SOT-23 TURRET, INDUCTOR, 4.7uH RLF7030 INDUCTOR, 4.7uH SLF6028 INDUCTOR, 10uH RLF5018 INDUCTOR, 6.8uH RLF5018 RES., CHIP, 7.5K, 1/16W, 5% 0402 RES., CHIP, 4.7K, 1/16W, 5% 0402 RES., CHIP, 10K, 1/16W, 1% 0402 RES., CHIP, 30K, 1/16W, 5% 0402 RES., CHIP, 13K, 1/16W, 5% 0402 Page 1 - of - 2 Manufacture / Part # Taiyo Yuden, LMK325BJ106MN Taiyo Yuden, EMK325BJ106MN Taiyo Yuden, JMK316BJ226ML AVX, 0603ZC224MAT2A AVX, 0402YC153MAT2A MuRata, GRM21BR71A225KA01L AVX, 0603YD474MAT2A AVX, 0402YD473KAT2A Taiyo Yuden, GMK325BJ225MN AVX, 04025C272MAT2A AVX, 04025C222MAT2A AVX, 04025C472MAT2A AVX, 04025C152MAT2A Taiyo Yuden, GMK212BJ474MG AVX, TAJC686M016R AVX, 04025C101MAT2A AVX, 04025A100KAT2A TAIYO YUDEN, EMK212BJ105MG TAIYO YUDEN, LMK212BJ105MG Diodes Inc., B230A-13 CENTRAL SEMI., CMDSH-3-LTC ZETEX, ZHCS400TA Diodes Inc., B240A-13 VISHAY, SI2343DS MILL-MAX, 2501-2 TDK, RLF7030T-4R7M3R4 TDK, SLF6028T-4R7M1R6 TDK, RLF5018T-100MR94 TDK, RLF5018T-6R8M1R1 AAC, CR05-752JM AAC, CR05-472JM AAC, CR05-1002FM AAC, CR05-303JM AAC, CR05-133JM Bill Of Material Demo Bd. #697A Linear Technology Corporation LT1943EFE 6/20/2005 Item Qty Reference 35 36 37 38 39 40 41 42 1 1 1 1 1 1 1 1 R2 R3 R6 R9 R15 U1 Part Description RES., CHIP, 16.5K, 1/16W, 1% 0402 RES., CHIP, 80.6K, 1/16W, 1% 0402 RES., CHIP, 95.3K, 1/16W, 1% 0402 RES., CHIP, 232K, 1/16W, 1% 0402 RES., CHIP, 100K, 1/16W, 5% 0402 I.C.LT1943EFE, TSSOP28FE PRINTED CIRCUIT BOARD STENCIL Page 2 - of - 2 Manufacture / Part # AAC, CR05-1652FM AAC, CR05-8062FM AAC, CR05-9532FM AAC, CR05-2323FM AAC, CR05-104JM LINEAR., LT1943EFE FAB., DEMO CIRCUIT 697A STENCIL 697A