DEMO MANUAL DC1807A LTC3869EUFD Dual, 2-Phase Synchronous Step-Down DC/DC Controllers DESCRIPTION Demonstration circuit 1807A is a dual output, dual phase synchronous buck converter featuring the LTC3869EUFD. The demo board uses a high density, two sided drop-in layout. The power components, excluding the bulk output and input capacitors, fit within a 1.35” × 0.75” area on the top layer. The control circuit resides in a 0.60” × 0.75” area on the bottom layer. The package style for the LTC3869EUFD is a 4mm × 5mm 28-lead QFN with an exposed ground pad. The main features of the board include an internal 5V linear regulator for bias, RUN pins for each output, an EXTVCC pin and a PGOOD signal. The board can be configured for either CCM (original setting), Burst Mode operation, or pulse-skipping operation with the mode jumper. The board also has optional resistors for single output/dual phase operation, rail tracking and synchronization to an external clock. PERFORMANCE SUMMARY PARAMETER Two versions of the board are available. DC1807A-A has an on-board sense resistor for current feedback, while the DC1807A-B is configured with a DCR sense circuit that allows the converter to use the inductors DCR as the sense element instead of the on-board sense resistors to save cost and board space and improves efficiency. The input voltage range is 4.5V to 14V, output voltages and currents are 1.5V/15A and 1.2V/15A. The LTC3869 datasheet gives a complete description of the part, operation and application information. The datasheet must be read in conjunction with this demo manual for DC1807A. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, μModule, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. (TA = 25°C) CONDITIONS VALUE Minimum Input Voltage 4.5V Maximum Input Voltage 14V Output Voltage VOUT1 VIN = 4.5V to 14V, IOUT1 = 0A to 15A Output Voltage VOUT2 VIN = 4.5V to 14V, IOUT2 = 0A to 15A 1.2V±2% Typical Output Ripple VOUT VIN = 12V, IOUT1 = 15A (20MHz BW) <30mVP-P* VIN = 12V, IOUT2 = 15A (20MHz BW) Nominal Switching Frequency Efficiency 1.5V±2% <30mVP-P* 400kHz DC1807A-A DC1807A-B VOUT1 = 1.5V, IOUT1 = 15A; VIN = 12V 88.7%** Typical 86.7%** Typical VOUT2 = 1.2V, IOUT2 = 15A; VIN = 12V 89.1%** Typical 87.4%** Typical *Measured at bulk output capacitor **See Figures 3 and 4 for efficiency curves dc1807af 1 DEMO MANUAL DC1807A QUICK START PROCEDURE Demonstration circuit 1807A is easy to set up to evaluate the performance of the LTC3869EUFD. 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. Make sure jumpers are in the following positions: JUMPER POSITION JP1 ON JP2 ON JP3 CCM 2. With power off, connect the input power supply to VIN and GND. Connect active loads to outputs. 3. Turn on the power at the input. NOTE. Make sure that the input voltage does not exceed 28V. 4. Check for the proper output voltages. VOUT1 = 1.470V to 1.530V, VOUT2 = 1.176V to 1.224V, 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 loads within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. 6. Different operating modes can be evaluated by changing position of jumper JP3. V A VOUT1 Load A V POWER SUPPLY A VOUT2 Load V Figure 1. Proper Measurement Equipment Setup dc1807af 2 DEMO MANUAL DC1807A QUICK START PROCEDURE Figure 2. Measuring Output Voltage Ripple Rail Tracking Demonstration circuit 1807A is setup for independent turn-on of VOUT1 and VOUT2. The ramp-rate for VOUT1 is determined by the TRK/SS1 cap at C2 and the ramp-rate for VOUT2 is determined by the TRK/SS2 cap at C47. The turn-on of one rail will not affect the other for the original demo board. This board can be modified on the bench to allow VOUT1 to track an external signal. It can also be modified to allow VOUT2 to track VOUT1 or to allow VOUT2 to track an external signal. Tables 2 and 3 cover the rail tracking options for each rail, with the –B version used as an example. Table.1 VOUT1 Tracking Options for a 1.5V Output. TRACK 1 DIVIDER CONFIGURATION TRK/SS1 CAPACITOR R3 R2 C2 Soft Start Without Tracking 0Ω OPEN 0.1μF External Coincident Tracking 17.8kΩ 20.0kΩ OPEN Table.2 VOUT2 Tracking Options for a 1.2V Output. TRACK 2 DIVIDER CONFIGURATION R36 TRK/SS2 CAPACITOR R34 R37 C47 Soft Start Without Tracking 0Ω OPEN OPEN 0.1μF Coincident Tracking to VOUT1 (1.5V) 0Ω 10.0kΩ 20.0kΩ OPEN External Coincident Tracking 17.8kΩ OPEN 20.0kΩ OPEN Single Output/Dual Phase Operation A single output/dual phase converter may be preferred for high output current applications. The benefits of single output/dual phase operation is lower ripple current through the input and output capacitors, improved load step response and simplified thermal design. To implement single output / dual phase operation, make the following modifications: 2. Tie ITH1 to ITH2 by stuffing 0 at R49. Turn on the power at the input. 3. Tie VFB1 to VFB2 by stuffing 0 at R50. 4. Tie TRK/SS1 to TRK/SS2 by stuffing 0 at R52. 5. Tie RUN1 to RUN2 by stuffing 0 at R55. 6. Remove the redundant ITH compensation network and VFB divider. 1. Tie VOUT1 to VOUT2 by tying together the exposed copper pads near J3 and J5 at the edge of the board. Use a piece of heavy copper foil. dc1807af 3 DEMO MANUAL DC1807A QUICK START PROCEDURE 95 90 85 EFFICIENCY (%) 80 75 70 65 6.5VIN,1.5VOUT, RSENSE, 400kHz 12VIN,1.5VOUT, RSENSE, 400kHz 60 14VIN,1.5VOUT, RSENSE, 400kHz 55 50 0 3 6 9 12 15 LOAD CURRENT (A) 95 90 85 EFFICIENCY (%) 80 75 70 65 6.5VIN,1.2VOUT, RSENSE, 400kHz 60 12VIN,1.2VOUT, RSENSE, 400kHz 14VIN,1.2VOUT, RSENSE, 400kHz 55 50 0 3 6 9 12 15 LOAD CURRENT (A) Figure 3. Typical Efficiency Curves vs Load Current with A-A (RSENSE) Board for: (A) 1.5V Rail and (B) 1.2V Rail dc1807af 4 DEMO MANUAL DC1807A QUICK START PROCEDURE 95 90 EFFICIENCY (%) 85 80 75 70 65 6.5VIN,1.5VOUT, DCR SENSE, 400kHz 60 12VIN,1.5VOUT, DCR SENSE, 400kHz 55 14VIN,1.5VOUT, DCR SENSE, 400kHz 50 0 3 6 9 12 15 LOAD CURRENT (A) 95 90 EFFICIENCY (%) 85 80 75 70 65 6.5VIN,1.2VOUT, DCR SENSE, 400kHz 60 12VIN,1.2VOUT, DCR SENSE, 400kHz 55 14VIN,1.2VOUT, DCR SENSE, 400kHz 50 0 3 6 9 12 15 LOAD CURRENT (A) Figure 4. Typical Efficiency Curves vs Load Current with A-B (DCR Sense) Board for: (A) 1.5V Rail and (B) 1.2V Rail dc1807af 5 DEMO MANUAL DC1807A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP, 180μF 20% 16V OSCON CAP, 1210 10μF 10% 16V X5R CAP, 1210 100μF 20% 6.3V X5R CAP, 7343 330μF 20% 2.5V POSCAP CAP, 0603 0.1μF 10% 25V X7R CAP, 0805 4.7μF 10% 6.3V X5R CAP, 0603 100pF 5% 25V X7R CAP, 0603 220pF 5% 25V X7R CAP, 0603 1μF 20% 16V X7R CAP, 0603 1nF 10% 50V X7R DIODE,CMDSH-3 SOD323 XSTR, N-CHANNEL MOSFET XSTR, N-CHANNEL MOSFET RES, 2010 0.002Ω 5% 1/2W RES, 0603 0Ω JUMPER RES, 0603 100Ω 5% 1/10W RES, 0603 10kΩ 1% 1/16W RES, 0603 2.2Ω 5% 1/10W RES, 0603 30.1kΩ 1% 1/10W RES, 0603 5.9kΩ 1% 1/10W RES, 0603 20kΩ 1% 1/10W RES, 0603 102kΩ 5% 1/10W RES, 0603 100kΩ 5% 1/10W IC, Dual, 2-Phase Synchronous StepDown DC/DC Controllers IND, 0.47μH SANYO OSCON 16SVP180MX TAIYO YUDEN EMK325BJ106KN-T TDK C3225X5R0J107MT SANYO 2R5TPE330M9 TDK C1608X7R1E104K AVX 08056D475KAT AVX 06033C101JAT AVX 06033C221JAT2A AVX 0603YC105MAT2A AVX 06035C102KAT CENTRAL CMDSH-3-LTC INFINEON BC050NE2LS INFINEON BSC010NE2LS VISHAY WSL20102L000FEA PANASONIC ERJ3GEY0R00V VISHAY CRCW0603100RJNEA VISHAY CRCW060310K0FKEB YAYEO RC0603JR-072R2 YAYEO RC0603FR-0730K1 VISHAY CRCW06035K9FKEA YAYEO RC0603FR-0720K VISHAY CRCW0603102KJNEA VISHAY CRCW0603100KJNEB LINEAR TECH.LTC3869EUFD Required Circuit Components 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 2 2 4 5 3 1 1 1 2 2 2 2 2 7 4 1 1 1 2 3 1 1 1 CIN1 CIN2, CIN3 COUT1, COUT4 COUT2, COUT3, COUT5, COUT6 C2, C17, C20, C21, C47 C11, C32, C36 C42 C43 C50 C14, C15, C41, C44 D1, D2 Q1, Q3 Q2, Q4 RS1, RS2 R1, R3, R9, R25, R36, R48, R54 R29, R30, R39, R40 R4 R18 R27 R31, R35 R32, R33, R43 R10 R46 U1 25 2 L1, L2 VITEC 59PR9875, 0.4μH Additional Circuit Components 1 0 CIN4, CIN5 CAP, 1210 OPTION OPTION 2 0 C1,C37,C38,C48,C49 CAP, 0603 OPTION OPTION 3 0 R2, R26, R28, R34, R37, R38, R41, R42, R44, R45, R47, R49, R50, R51, R52, R53, R55, R60, R61, R62 RES, 0603 OPTION OPTION 4 0 Q5, Q6, Q7, Q8 DO NOT STUFF OPTION 12 E1-E6, E9-E14 TURRET MILL-MAX 2501-2-00-80-00-00-07-0 Hardware 1 2 2 JP1, JP2 HEADER, 3 PIN, 2mm SAMTEC TMM-103-02-L-S 3 1 JP3 HEADER, 4 PIN SAMTEC TMM-104-02--L-S 4 6 J1, J2, J3, J4, J5, J6 JACK, BANANA KEYSTONE 575-4 5 3 JP1-JP3 SHUNT, 2mm SAMTEC 2SN-BK-G dc1807af 6 DEMO MANUAL DC1807A SCHEMATIC DIAGRAM dc1807af 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. 7 DEMO MANUAL DC1807A 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 © 2004, Linear Technology Corporation dc1807af 8 Linear Technology Corporation LT 0611 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011