DEMO MANUAL DC1537A LT3992A Monolithic Dual Tracking 3A Step-Down Switching Regulator DESCRIPTION Both converters are synchronized to either a common external clock input or a resistor programmable 250kHz to 2MHz internal oscillator. At all frequencies, a 180 phase shift between channels is maintained, reducing voltage ripple. Programmable frequency allows optimization between efficiency and external component size. Each output can be independently disabled using its own SHDN pin and be placed in a low quiescent current shutdown mode. The LT3992 data sheet gives complete description of the device, operation and application information. The data PERFORMANCE SUMMARY PARAMETER sheet must be read in conjunction with this quick start guide for demo circuit 1537A. Design files for this circuit board are available at http://www.linear.com/demo 100 95 90 EFFICIENCY (%) The demo circuit 1537A is a dual current mode PWM step-down DC/DC converter featuring LT(R)3992. The demo circuit is designed for 5V and 3.3V outputs from a 7V to 60V input. The current capability of each channel is up to 3A when running individually and 2A when both are sourcing the same current without special heat sinking. Individual soft-start, current limit, comparator, input voltage for each output as well as frequency division and synchronous and clock output functions simplify the complex design of dual-output power converters 85 80 75 70 65 VOUT1 = 5V VOUT2 = 3.3V 60 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 LOAD CURRENT FOR SIGNAL CHANNEL (A) DC1537a F01 Figure 1. Single Channel Efficiency at VIN = 24V, f = 300kHz L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Specifications are at TA = 25C. CONDITIONS VALUE Minimum Input Voltage 7V Maximum Input Voltage 60V (For Transient. Continuous Operation if D3 and D4 Are Replaced with Higher Voltage Rated Schottky Diodes) Output Voltage VOUT1 VIN = 7~ 60V Output Voltage VOUT2 VIN = 7~ 60V Switching Frequency 5.0V 3% 3.3V 3% 300kHz 10% Maximum Output Current IOUT1 VIN = 7~ 60V 3A Individually, 2A Both Running Maximum Output Current IOUT2 VIN = 7~ 60V 3A Individually, 2A Both Running Voltage Ripple VOUT1 VIN = 12V, IOUT1 = 3A <20mV Voltage Ripple VOUT2 VIN = 12V, IOUT2 = 3A <20mV dc1537af 1 DEMO MANUAL DC1537A DESCRIPTION 100 0.9 0.9 VOUT1 = 5V/3A, VOUT2 NO LOAD VOUT2 = 3.3V/3A, VOUT1 NO LOAD 95 TJ PIN VOLTAGE (V) EFFICIENCY (%) 85 80 75 0.8 TJ PIN VOLTAGE (V) 0.8 90 0.7 0.6 0.7 0.6 70 0.5 0.5 65 60 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 LOAD CURRENT FOR BOTH CHANNELS (A) 0.4 0.4 5 10 15 25 30 35 40 VIN (V) 5 10 15 20 25 30 35 40 VIN (V) DC1537a F03 DC1537a F02 Figure 2. Dual Channel Efficiency at VIN = 24V, f = 300kHz 20 Figure 3. DC1537A TJ Pin Voltage When Channels Running Individually at 3A Load (TA = 25C) DC1537a F04 Figure 4. DC1537A TJ Pin Voltage When Both Channels Sourcing 2A Current at Meantime (TA = 25C) QUICK START PROCEDURE Demo circuit 1537A is easy to set up to evaluate the performance of the LT3992. Refer to Figure 5 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 6 for proper scope probe technique. 1. Place JP1 on the SINGLE position. 2. With power off, connect the input power supply to VIN1 and GND. (Connect another input power supply to VIN2 and GND if DUAL is selected.) 4. Check for the proper output voltages. 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 voltages are established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. ADDITIONAL NOTES If an EMI filter is desirable on VIN1, it can be feasibly installed on the back of the board in the optional circuit area. However, a trace cut is required for the insertion of the optional circuit. See Figure 7 for the cut line. 3. Turn on the power at the input. NOTE. Make sure that the input voltage does not exceed 60V (Due to part selection on D3 and D4, 60V is for transient purpose. Continuous operation can be available after D3 and D4 are replaced with higher voltage rated schottky diodes). dc1537af 2 DEMO MANUAL DC1537A QUICK START PROCEDURE Figure 5. DC1537A Proper Equipment Setup GND VIN Figure 6. Measuring Input or Output Ripple Figure 7. Cut Line for the EMI Filter Installation dc1537af 3 DEMO MANUAL DC1537A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 4 C2, C3, C22, C23 CAP, 1210 2.2F 10% 100V X7R AVX 12101C225KAT2A 2 2 C4, C5 CAP, 0603 0.47F 10% 25V X7R MURATA GRM188R71E474KA12D 3 2 C7, C8 CAP, 1210 100F 20% 10V X5R TAIYO YUDEN LMK325ABJ107MM-T 4 2 C10, C11 CAP, 0402 22pF 10% 25V NPO AVX 04023A220KAT2A 5 2 C12, C13 CAP, 0402 0.1F 10% 16V X7R TDK C1005X7R1C104K 6 2 C14, C15 CAP, 0402 680pF 10% 25V X7R AVX 04023C681KAT2A 7 2 C16, C17 CAP, 0402 33pF 10% 25V NPO AVX 04023A330KAT 8 1 C24 CAP, 0402 10nF 10% 16V X7R MURATA GRM155R71C103KA01D 9 2 D1, D5 DIODE, SCHOTTKY BARRIER SOD123 ON SEMICONDUCTOR MMSD701T1G 10 2 D2, D4 DIODE, SCHOTTKY RECTIFIER SMB DIODES INC. B360B 11 1 L1 IND, 22H NIC NPIM104B220MTRF 12 1 L2 IND, 10H NIC NPIM104B100MTRF 13 2 R1, R2 RES, 0603 1k 1% 1/16W NIC NRC06F1001TRF 14 1 R5 RES, 0402 42.2k 1% 1/16W VISHAY CRCW040242K2FKED 15 1 R6 RES, 0402 24.9k 1% 1/16W VISHAY CRCW040224K9FKED 16 2 R7, R8 RES, 0402 100k 5% 1/16W VISHAY CRCW0402100KJNED 17 2 R9, R10 RES, 0402 8.06k 1% 1/16W VISHAY CRCW04028K06FKED 18 2 R11, R12 RES, 0402 100k 1% 1/16W VISHAY CRCW0402100KFKED 19 2 R13, R14 RES, 0402 30k 1% 1/16W NIC NRC04F3002TRF 20 1 R15 RES, 0402 7.32k 1% 1/16W VISHAY CRCW04027K32FKED 21 1 R16 RES, 0402 20k 1% 1/16W VISHAY CRCW040220K0FKED 22 1 R17 RES, 0402 40.2k 1% 1/16W VISHAY CRCW040240K2FKED 23 1 U1 IC, STEP-DOWN REGULATOR LINEAR TECHNOLOGY LT3992EFE Additional Demo Board Circuit Components 1 2 C1, C21 CAP, 22F 20% 100V OSCON SUNCON 100CE22BS 2 0 C6, C9 CAP, 0805 10F 10% 16V X5R OPTION MURATA GRM21BR61C106KE15L OPTION 3 0 C18 CAP, 22uF 20% 100V OSCON OPTION SANYO 100CE22BS OPTION 4 0 C19 CAP, 0603 0.01F 10% 100V X7R OPTION AVX 06031C103KAT OPTION 5 0 C20 CAP, 1210 2.2F 10% 100V X7R OPTION AVX 12101C225KAT2A OPTION 6 0 C25 CAP, 0402 10nF 10% 16V X7R OPTION MURATA GRM155R71C103KA01D OPTION 7 0 D3, D6 DIODE, SCHOTTKY BARRIER SOD123 OPTION ON SEMICONDUCTOR MMSD701T1G OPTION 8 0 D7, D8 DIODE, OPT OPTION 9 0 R18 RES, 0603 0 JUMPER OPTION VISHAY CRCW06030000Z0EA OPTION 10 0 FB1 FERRITE BEAD OPTION TAIYO YUDEN FBMJ3216HS800 OPTION 11 0 L3 IND, 22H OPTION VISHAY IHLP4040DZ-01 OPTION Hardware/Components (For Demo Board Only) 1 1 JP1 HEADER,4-PIN SAMTEC TMM-104-02-L-S 2 8 TP1, TP2, TP5 TO TP8, TP16, TP17 TURRET MILL-MAX 2501-2-00-80-00-00-07-0 3 9 TP3, TP4, TP9 TO TP15 TURRET MILL-MAX 2308-2-00-80-00-00-07-0 4 1 JP1 SAMTEC 2SN-BK-G SHUNT,2mm dc1537af 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 * C19 0.01uF 100V OPT 0603 TP13 TP11 TP9 TP7 TP5 TP3 TP2 TP1 VIN1 OPT 237,21$/&,5&8,7 C20 2.2uF 100V OPT 1210 OPT 0.1uF C12 0603 R1 1k 1% C18 22uF 100V OPT * 5 [1] SEE QUICK START GUIDE FOR DETAILS ON JP1 SETTING AND INPUT VOLTAGE IMPLEMENTATION ORDER. 2. ALL CAPACITORS ARE 0402. ALL RESISTORS ARE 0402. SEE QUICK START GUIDE FOR DETAILS ON CURRENT CAPABILITY. + 22pF C10 B360B D2 4 C25 10nF OPT C16 33pF C14 680pF R13 30k 1% R11 100K 1% R9 8.06K 1% R5 42.2K 1% MMSD701T1G D1 C4 0.47uF 0603 D6 MMSD701T1G OPT VOUT2 VIN1 R7 100K D7 OPT C22 2.2uF VIN1 100V 1210 L3 22uH C7 100uF 10V 1210 C2 2.2uF 100V 1210 FB1 BEAD C6 10uF 16V OPT 0805 VOUT1 22uF 100V + C1 NOTES: UNLESS OTHERWISE SPECIFIED, SYNC SS1 CMPO1 GND 5V/2A VOUT1 SHDN1 GND 7V - 60V VIN1 (300kHz) R15 7.32k 1% L1 22uH U1 R16 20k 1% 15 10 5 3 1 27 30 32 33 34 7 8 9 4 2 38 6 35 NC NC NC NC NC DIV RT/SYNC VC1 ILIM1 SS1 CMPO1 CMPI1 FB1 VOUT1 IND1 SW1 BST1 SHDN1 LT3992EFE VIN1 36 4 3 17 19 21 31 37 28 29 26 25 24 13 12 7+,6&,5&8,7,635235,(7$5<72/,1($57(&+12/2*<$1' 6833/,(')2586(:,7+/,1($57(&+12/2*<3$576 3 C11 22pF R6 24.9K 1% C5 0.47uF 0603 DESCRIPTION R8 100K D5 MMSD701T1G C13 D8 OPT 0603 R2 1k 1% VIN2 C23 2.2uF 100V 1210 PRODUCTION C3 2.2uF 100V 1210 2 '$7( Tuesday, January 17, 2012 1$ 6,=( TECHNOLOGY 0.1uF DATE VIN2 TEMP CLKOUT SS2 CMPO2 GND VOUT2 9$ SHDN2 GND * 1 6+((7 2) 5(9 0F&DUWK\%OYG 0LOSLWDV&$ 3KRQH ZZZOLQHDUFRP )D[ /7&&RQILGHQWLDO)RU&XVWRPHU8VH2QO\ TP15 TP14 TP12 TP10 TP8 TP6 TP4 APPROVED EDWIN L. 7V - 60V TP17 TP16 C21 22uF 100V 01-17-12 C9 10uF 16V OPT 0805 + 1 DUAL MONOLITHIC STEP-DOWN CONVERTER ,&12 LT3992EFE DEMO CIRCUIT 1537A EDWIN L. 7,7/( 6&+(0$7,& JW 6&$/( 121( $33(1* 3&%'(6 $33529$/6 OPT R18 C17 33pF R14 30k 1% C15 680pF R12 100K 1% R10 8.06K 1% C8 100uF 10V 1210 B360B D4 VOUT1 D3 MMSD701T1G OPT 2 REV 11 R17 40.2k 1% VIN2 ECO REVISION HISTORY VOUT2 C24 10nF L2 10uH DUAL 2 16 18 20 14 23 JP1 [1] CASCADE SINGLE &86720(5127,&( NC NC NC NC NC TJ CLKOUT VC2 ILIM2 SS2 CMPO2 CMPI2 FB2 VOUT2 IND2 SW2 BST2 SHDN2 VOUT1 2 1 INPUT MODE /,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 9(5,)<3523(5$1'5(/,$%/(23(5$7,21,17+($&78$/ $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&( VIN1 3 VIN2 4 22 PGND 39 5 A B C D DEMO MANUAL DC1537A SCHEMATIC DIAGRAM dc1537af 5 DEMO MANUAL DC1537A 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 dc1537af 6 Linear Technology Corporation LT 0212 * 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