DEMO MANUAL DC1731A-A/DC1731A-B LTC3646/LTC3646-1 High Efficiency Low Quiescent Current Step-Down Converter DESCRIPTION Demonstration circuit 1731A-A/1731A-B is a step-down DC/DC converter using LTC3646/LTC3646-1 monolithic synchronous buck regulator. The input voltage range is from 4V to 40V. The output voltage range of LTC3646 is 2V to 30V, for LTC3646-1 is 0.6V to 15V. It can deliver up to 1A of output current. At light load conditions, DC1731A can operate in Burst Mode(R) operation to improve the efficiency. The user can choose to use internal or external compensation. The switching frequency of LTC3646/ LTC3646-1 is programmable from 200kHz to 3MHz. It can PERFORMANCE SUMMARY PARAMETER be synchronized to an external clock through the MODE/ SYNC pin. The LTC3646/LTC3646-1 data sheet must be read in conjunction with this demo manual prior to working on or modifying demonstration circuit 1731A. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Specifications are at TA = 25C CONDITIONS/NOTES Input Voltage Range Output Voltage VOUT VALUE 4V to 40V Jumper Selectable Maximum Continuous Output Current 3.3V, 5V 1A Default Operating Frequency 1.5MHz Efficiency VIN = 12V, VOUT = 5V, IOUT = 1A Load Transient VIN = 12V, VOUT = 5V 91.0% See Figure 3 See Figure 4 dc1731aabf 1 DEMO MANUAL DC1731A-A/DC1731A-B QUICK START PROCEDURE Demonstration circuit 1731A is an easy way to evaluate the performance of the LTC3646/LTC3646-1. Please refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 3. Turn on the power at the input. Increase VIN to 12V (Do not hot-plug the input supply or apply more than the rated maximum voltage of 40V to the board or the part may be damaged). The output voltage should be regulated and deliver the selected output voltage 2%. 1. Place jumpers in the following positions for a typical application: MODE EXTVCC RUN VOUT SELECT FCC GND ON 3.3V 4. Vary the input voltage from 4V to 40V and adjust the load current from 0A to 1A. Observe the output voltage regulation, ripple voltage, efficiency, and other parameters. 2. With power off, connect the input power supply, load and meters as shown in Figure 1. Preset the load to 0A and VIN supply to be 0V. 5. To measure input or output ripple, please refer to Figure 2 for proper measurement setup. + + + - VIN - + - + LOAD - + Figure 1. Proper Measurement Equipment Setup dc1731aabf 2 DEMO MANUAL DC1731A-A/DC1731A-B QUICK START PROCEDURE INPUT OR OUTPUT CAPACITOR Figure 2. Measuring VIN or VOUT Ripple LTC3646 Efficiency, VOUT = 5V 100 100 90 90 80 80 70 70 EFFICIENCY (%) EFFICIENCY (%) LTC3646 Efficiency, VOUT = 3.3V 60 50 40 30 VIN = 5V VIN = 12V VIN = 18V VIN = 24V VIN = 36V 20 10 0 0 0.2 0.4 0.6 LOAD (A) 0.8 1.0 60 50 40 30 VIN = 12V VIN = 18V VIN = 24V VIN = 36V 20 10 0 0 0.2 0.4 0.6 LOAD (A) dc1731aab F03a (a) 0.8 1.0 dc1731aab F03b (b) Figures 3a and 3b. Measured DC1731A Efficiency at Different VIN and VOUT (Burst Mode Operation Enabled) VOUT: 100mV/DIV IOUT_STEP: 500mA/DIV dc1731aab F04 VIN = 12V VO = 5V 0A TO 0.5A LOAD STEP Figure 4. Measured Load Transient Responses dc1731aabf 3 DEMO MANUAL DC1731A-A/DC1731A-B PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 U1 IC, HIGH EFFICIENCY LOW QUIESCENT CURRENT STEP-DOWN CONVERTER LTC3646EDE FOR DC1731A-A LTC3646EDE-1 FOR DC1731A-B 2 2 CIN2, CIN3 CAP, 1210 10F 20% 50V X5R TAIYO YUDEN UMK325BJ106MM-T 3 1 COUT1 CAP, 1210 4.7F 20% 16V X7R TAIYO YUDEN EMK325BJ475MN-T 4 1 COUT2 CAP, 1210 10F 20% 16V X5R TDK C3225X7R1C106M 5 1 C1 CAP, 0603 4.7F 10% 10V X5R TDK C1608X5R1A475K-T 6 1 C2 CAP, 0603 0.1F 10% 50V X7R AVX 06035C104KAT2A 7 1 C3 CAP, 0603 5.6pF 0.25pF 50V NPO AVX 06035A5R6CAT2A 8 1 C5 CAP, 0603 100pF 10% 50V X7R AVX 06035C101KAT2A 9 1 C6 CAP, 0805 2.2F 20% 50V Y5V TDK C2012Y5V1H225Z 10 2 C7, C9 CAP, 0805 1F 10% 50V X7R MURATA GRM21BR71H105KA12L 11 1 L1 IND, 4.7H COILCRAFT XAL5030-472MEB 12 1 R2 RES, 0603 2 5% 1/10W VISHAY CRCW06032R00FNEA 13 1 R3 RES, 0603 100k 5% 1/10W VISHAY CRCW0603100KJNEA 14 1 R7 RES, 0603 60.4k 1% 1/10W VISHAY CRCW060360K4FKED 15 1 R9 RES, 0603 200k 1% 1/10W VISHAY CRCW0603200KFKEA 16 1 R10 RES, 0603 137k 1% 1/10W YAGEO RC0603FR-07137KL 17 1 R11 RES, 0603 84.5k 1% 1/10W VISHAY CRCW060384K5FKEA 18 1 R12 RES, 0603 619k 1% 1/10W VISHAY CRCW0603619KFKEA Additional Demo Board Circuit Components 1 0 CIN1 CAP, 56F 20% 50V ALUM. ELEC. OPTION SUN ELEC 50HVH56M OPTION 2 0 C4, C8 CAP, 0603 OPTION OPTION 3 0 D1 DIODE, OPTION OPTION 4 0 R4, R5, R6 RES, 0603 OPTION OPTION Hardware: For Demo Board Only 1 11 E1-E11 TURRET MILL-MAX 2501-2-00-80-00-00-07-0 2 1 JP1 HEADER, 2mm, 3PIN SAMTEC TMM-103-02-L-S 3 2 JP2, JP5 HEADER, 3PIN, DBL ROW 2mm SAMTEC TMM 103-02-L-D 4 1 JP3 HEADER, 2mm DBL ROW (2X2) 4PIN SAMTEC TMM-102-02-L-D 5 4 MH1, MH2, MH3, MH4 STANDOFF, SNAP ON KEYSTONE_8831 6 4 JP1, JP2, JP3, JP5 SHUNT, 2mm SAMTEC 2SN-BK-G dc1731aabf 4 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C D E10 E9 E5 INTVCC CIN2 10uF 50V 1210 4 6 5 BURST R5 OPT FCC SYNC JP2 2 3 MODE / SYNC R3 100k + CIN1 OPT 1 INTVCC PG VIN INTVCC CIN3 10uF 50V 1210 R6 OPT R7 60.4k 1% [3] [2] VERSION VIN 5 IC VOUT JP1 R4 3 2 1 R9 200k 1% C4 OPT 0805 1uF C7 3 4 7 6 13 U1 [3] R2 2 ITH RT 0805 C8 INTVCC OPT C6 2.2uF 50V MODE/SYNC PGOOD RUN 2 5 9 10 4 3 7+,6&,5&8,7,635235,(7$5<72/,1($57(&+12/2*<$1' 6833/,(')2586(:,7+/,1($57(&+12/2*<3$576 3 C1 4.7uF L1 4.7uH REV 5 3 1 R10 137k 1% '$7( N/A 6,=( R11 84.5k 1% R12 619k 1% TECHNOLOGY VOUT C9 1uF 0805 E11 E3 GND GND VOUT [2] GND INTVCC EXTVCC 3 0F&DUWK\%OYG 0LOSLWDV&$ 3KRQH ZZZOLQHDUFRP )D[ /7&&RQILGHQWLDO)RU&XVWRPHU8VH2QO\ COUT2 10uF 16V 1210 E4 E7 E6 DATE 09/21/12 2 10/04/12 10:19:29 1 6+((7 1 DEMO CIRCUIT 1731A-A/B 2) 1 HIGH EFFICIENCY LOW QUIESCENT CURRENT STEP-DOWN CONVERTER ,&12LTC3646EDE / LTC3646EDE-1 5(9 7,7/( 6&+(0$7,& VOUT SELECT JP3 6 COUT1 4.7uF 16V 1210 EXTVCC 4 JP5 VOUT GND 2 E8 YAN L. VOUT APPROVED PROTO 1 DESCRIPTION EXTVCC C3 5.6pF COILCRAFT XAL5030-472MEB C2 0.1uF D1 DFLS1200 OPT SW 6&$/( 121( ECO EXTVCC $33529$/6 VFB VON SW BOOST /,1($57(&+12/2*<+$60$'($%(67())25772'(6,*1$ &,5&8,77+$70((76&86720(56833/,('63(&,),&$7,216 +2:(9(5,75(0$,167+(&86720(5 65(63216,%,/,7<72 3&%'(6 0, 9(5,)<3523(5$1'5(/,$%/(23(5$7,21,17+($&78$/ $33(1* <$1/ $33/,&$7,21&20321(1768%67,787,21$1'35,17(' &,5&8,7%2$5'/$<2870$<6,*1,),&$17/<$))(&7&,5&8,7 3(5)250$1&(255(/,$%,/,7<&217$&7/,1($5 7(&+12/2*<$33/,&$7,216(1*,1((5,1*)25$66,67$1&( &86720(5127,&( C5 100pF OPT RUN INTVCC OFF ON NOTES: UNLESS OTHERWISE SPECIFIED, 1. ALL RESISTOR AND CAPACITOR CASE SIZE ARE 0603. SYNC PGOOD GND [2] VIN E2 SVIN 8 PVIN SVIN 1 E1 14 SVIN SGND 12 EXTVCC PGND 15 11 INTVCC REVISION HISTORY 5V 2 3.3V 3 2 1 4 4 3 5 A B C D DEMO MANUAL DC1731A-A/DC1731A-B SCHEMATIC DIAGRAM dc1731aabf 5 DEMO MANUAL DC1731A-A/DC1731A-B DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright (c) 2004, Linear Technology Corporation dc1731aabf 6 Linear Technology Corporation LT 1112 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com (c) LINEAR TECHNOLOGY CORPORATION 2012