QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797 1MHZ SYNCHRONOUS BUCK-BOOST IN 3MM X 3MM DFN LTC3440EDD DESCRIPTION Demonstration Circuit 797 is a constant-frequency synchronous Buck-Boost converter using the LTC3440EDD. The input range is from 2.5V to 5.5V, making it ideal for single-cell Lithium-Ion or three-cell NiCd/NiMH battery applications. This converter provides up to 95% efficiency, much higher than traditional Buck-Boost converters. For 2.5V minimum input voltage, this converter can provide up to 540mA load current. The output voltage is set at 3.3V. A different output voltage in the range of 2.5V to 5.25V can be obtained by changing one of the feedback resistors. The switching frequency is set at 1MHz, which is a good trade-off between efficiency and size. The frequency can be modified by changing R6 or by synchronizing to an external clock. In shutdown, the IC itself draws less than 1µA. When using long wire connections to the input sources (such as wall adaptors), there can be input over voltage transients during initial plug-in. C8 is installed on DC797 to damp the possible voltage transients. C8 is not needed for any application when the 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. LTC is a trademark of Linear Technology Corporation Table 1. Performance Summary (TA = -40°°C to 85°°C unless otherwise noted) PARAMETER CONDITION VALUE Minimum Input Voltage 2.5V Maximum Input Voltage 5.5V Output Voltage VOUT VIN = 2.5V to 5.5V, IOUT = 0mA to 540mA 3.3V ±4% Maximum Output Current VIN = 2.5V 540mA Maximum Output Current VIN = 2.7V 600mA Typical Output Ripple VOUT VIN = 2.5V, IOUT = 500mA (20MHz BW) 12mVPP (measured at C2) Typical Switching Frequency Efficiency (Fixed Freq.) On/Off Control 22mVPP (measured across E4 and E5) 1MHz VIN = 4.2V, IOUT = 100mA 94% Typical VIN = 4.2V, IOUT = 500mA 91% Typical Off 0.4V MAX On 1.5V MIN 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797 1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN QUICK START PROCEDURE Demonstration circuit 797 is easy to set up to evaluate the performance of the LTC3440EDD . 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 Vin or Vout and GND terminals. See Figure 2 for proper scope probe technique. 1. Place jumpers in the following positions: 2. With power off, connect the input power supply to Vin and GND. 3. Turn on the power at the input. NOTE: Make sure that the input voltage does not exceed 5.5V. 4. Check for the proper output voltage. Vout = 3.17V to 3.43V. NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 5. Once the proper output voltage is established, ad- JP1 RUN JP2 FIXED FREQ. just the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797 1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN Figure 1. Proper Measurement Equipment Setup GND VIN Figure 2. Measuring Input or Output Ripple 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 797 1MHZ SYNCHRONOUS BUCK-BOOST CONVERTER IN 3MM X 3MM DFN Efficiency vs. Load 100% 90% 80% Efficiency% 70% 60% 50% 2.7Vin PWM 40% 3.6Vin PWM 30% 2.7Vin Burst 4.2Vin PWM 3.6Vin Burst 20% 4.2Vin Burst 10% 0% 0.1 1 10 100 1000 Iout (mA) Figure 3. Efficiency of DC797 Figure 4. Load Transient Response (Vin=3.6V; Channel 1: Vout, 100mV/div; Channel 2: Iout load step: 100mA to 500mA) 4 5 4 * 3 2 D3 IS RECOMMENDED FOR VIN>4.5V. PLEASE REFER TO DATASHEET FOR DETAILS. SUMIDA CDRH4D28C/100 L1 10UH 1 2 2 2 * 1 VIN +C8 C1 10UF 6.3V 1206 47UF,10V TAJB R4 1M 3 7 SHDN 8 2 1 SW2 VIN SHDN/SS C6 0.047UF R1 340K 1% VOUT 6 FB 9 R3 MODE/SYNC VC 10 RT GND 5 SYNC E3 C7 1UF 6.3V 0603 R5 2.2K E5 GND C5 10PF R7 4.87M R6 60.4K 1% C2 22UF,6.3V 1210 C4 560PF 15K R8 6.19M E2 C R2 200K 1% SYNC VIN B BURST MODE 1 2 GND C3 180PF 4 11 C SW1 E4 VOUT 3.3V VOUT PHILIPS U1 LTC3440EDD D3 POWERMITE ON SEMI OPT D1 PMEG2010EA PHILIPS D D2 PMEG2010EA 2 1 GND 1 D VIN E1 2.5V-5.5V 1 FIXED FREQ. 3 SHDN 1 B JP1 2 JP2 RUN 3 VIN IOUT 2.5V 540mA 2.7V 600mA NOTES: UNLESS OTHERWISE SPECIFIED A 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPS. ARE 0402. 2. INSTALL SHUNTS ON JP1 AND JP2 PIN 2 AND 3. CUSTOMER NOTICE CONTRACT NO. 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 5 4 3 APPROVALS TECHNOLOGY DRAWN: CHECKED: KIM T. APPROVED: 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only TITLE: A 1MHz SYNCHRONOUS BUCK-BOOST IN 3mm X 3mm DFN ENGINEER: DONGYAN Z. SIZE DESIGNER: A DWG NO. DC797A-1*LTC3440EDD DATE: Friday, August 20, 2004 2 SHEET 1 1 REV A OF 1 BILL OF MATERIALS DC797A-1 Linear Technology Corporation LTC3440EDD 6/20/2005 10:44 AM 1MHz SYNCHRONOUS BUCK-BOOST IN 3mm X 3mm DFN ENG.: DONGYAN ZHOU (23-30) 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 1 1 1 1 1 1 1 1 2 1 5 2 2 1 1 1 1 1 1 1 1 1 1 Part Description C1 C2 C3 C4 C5 C6 C7 C8 D1,D2 D3 E1,E2,E3,E4,E5 JP1,JP2 CAP., X5R, 10UF 6.3V,20%,1206 CAP., X5R, 22UF 6.3V,1210 CAP., X7R, 180PF 50V,0402 CAP., X7R, 560PF 50V,0402 CAP., NPO, 10PF 50V,0402 CAP., X5R, 0.047UF 10V CAP., X5R 1UF 6.3V,20%,0603 CAP., TANT, 47UF 10V, 3528 DIODE, SCHOTTKY,SOD323 DIODE, SCHOTTKY,POWERMITE TP, TURRET, .094" HEADER, 3PIN 1 ROW .079CC SHUNTS FOR JP1&JP2 PIN 2&3 SHUNT, 0.079" CENTER IND, 10UH, L-CDRH4D28C L1 R1 RES, CHIP 340K, 1%,0402 R2 RES, CHIP 200K, 1%,0402 R3 RES, CHIP 15K, 5%,0402 R4 RES, CHIP 1M, 5%,0402 R5 RES, CHIP 2.2K, 5%,0402 R6 RES, CHIP 60.4K, 1%,0402 R7 RES, CHIP 4.87M, 1%,0402 R8 RES, CHIP 6.19M, 1%,0402 IC, LTC3440EDD, 10-LEAD DFN3X3, DFN10DD U1 Page 1 - of - 1 Manufacture / Part # TAIYO YUDEN, JMK316BJ106ML TAIYO YUDEN, JMK325BJ226MM AVX, 04025C181MAT1A AVX, 04025C561MAT1A AVX, 04025A100KAT1A AVX, 0402ZD473MAT1A TAIYO YUDEN, JMK107BJ105MA AVX, TAJB476M010 PHILIPS, PMEG2010EA ON SEMI, MBRM120ET3 MILL-MAX, 2501-2 COMM-CON, 2802S-03-G1 COMM-CON, CCIJ2MM-138G SUMIDA, CDRH4D28C/100 AAC, CR05-3403FM AAC, CR05-2003FM AAC, CR05-153JM AAC, CR05-105JM AAC, CR05-222JM AAC, CR05-6042FM AAC, CR05-4874FM AAC, CR05-6194FM LINEAR TECH. LTC3440EDD