DEMO MANUAL DC1940A Low Quiescent Current, High Voltage Step-Down Converter DESCRIPTION Demonstration circuit 1940A is a low quiescent current, synchronous buck converter featuring the LTC®3891EUDC. This demo board converts a 16V to 60V voltage to a 12V at 15A output. The main features of this board include an internal LDO for gate drive power from VIN or EXTVCC, RUN and PGOOD pins, a mode selector that allows the converter to run in constant current mode (CCM), pulse-skipping or Burst Mode® operation, and selectable current limit. The DC1940A supports an adjustable output voltage, soft-start and tracking. The wide input voltage range of 16V to 60V is suitable for double battery automotive and distributed DC power systems where low quiescent current is important. The LTC3891 data sheet gives a complete description of this part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1940A. The 60V avalanche rated MOSFETs, which are used on DC1940A, can be operated at their rated voltage. However, if application derating requirements are stricter, MOSFETs with higher voltage rating can be used. PERFORMANCE SUMMARY PARAMETER Please note, MOSFETs with higher voltage ratings may affect the efficiency. If 60V MOSFETs are used, the MOSFET avalanche rating and testing is typically done with 30% over voltage margin (78V for 60V rated MOSFET). Please check with particular MOSFET manufacturer to ensure the avalanche voltage rating. The DC1940A supports the following MOSFET packages: LFPAK, PowerPAK SO-8 and Power 56. The subsequent logic level (SV gate) MOSFETs can be used with DC1940A. Si7850DP Vishay RJK0651DPB Renesas HAT2266H Renesas BSC100N06LS3 G Infineon FDMS86520L Fairchild For synchronization to an external clock, remove jumper JP2 and apply sync signal on terminal SYNC. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, 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 UNITS Minimum Input Supply Voltage 16 V Maximum Input Supply Voltage 60 V 12 ± 2% V Output Voltage Range VIN = 16V to 60V, IOUT1 = 0A to 5A Typical Switching Frequency Typical Output Ripple (VOUT, 12V) ILOAD = 15A Efficiency Typical (VOUT, 12V) 125 kHz 80 mV 97 % Supply Quiescent Current VIN = 24V; VOUT = 12V, IO = 0A, Burst Mode Operation 50.8 μA Supply Shutdown Current VIN = 24V 14.7 μA dc1940af 1 DEMO MANUAL DC1940A QUICK START PROCEDURE Demonstration circuit 1940A is easy to set up to evaluate the performance of the LTC3891EUDC. 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. 3. Turn on the power at the input. Check for the proper output voltages: VOUT1 = 11.9V to 12.4V NOTE: 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 load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. 1. Place jumper JP1 in the ON position. 2. With power off, connect the input power supply to VIN and GND. DC1940a F01 Figure 1. Proper Measurement Equipment Setup dc1940af 2 DEMO MANUAL DC1940A QUICK START PROCEDURE GND VIN DC1940a F02 Figure 2. Measuring Input or Output Ripple 99 98 16V 24V 48V 97 EFFICIENCY (%) 96 95 94 93 92 91 90 89 0.01 0.1 1 LOAD (A) 10 100 DC1940a F03 Figure 3. 12V Output, Efficiency vs Load, Burst Mode Operation, VIN 16V, 24V, 48V dc1940af 3 DEMO MANUAL DC1940A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 3 C1, C2, C10 CAP, X7R, 2.2μF 100V 10%, 1812 TDK, C4532X7R2A225K 2 1 C3 CAP, EL, 56μF/63V, F4 SUN EL, 63HVH56M 3 1 C4 CAP, X7R, 0.1μF 100V 10%, 0603 MURATA, GRM188R72A104KA35D 4 1 C5 CAP, NPO,10pF, 50V, 5%, 0603 AVX, 06031A100JAT2A 5 2 C9, C13 CAP, X7R, 0.1μF 50V 10%, 0603 TDK, C1608X7R1H104K 6 1 C6 CAP, X5R, 4.7μF, 16V, 10%, 0805 MURATA, GRM219R61C475KE15D 7 2 C7, C17 CAP, X7R, 1μF 16V, 10%, 0603 TDK, C1608X7R1C105K 8 1 C8 CAP, NPO, 2.2pF 50V, ±0.25pF, 0603 AVX, 06035A2R2CAT 9 1 C12 CAP, X7R, 4700pF, 10V, 5%, 0603 AVX, 0603ZC472JAT2A 10 1 C14 CAP, NPO, 47pF 50V, 5%, 0603 NIC, NMC0603NPO470J50TRPF 11 1 C15 CAP, X7R, 10μF 16V 10%, 1206 MURATA, GCM31CR71C106KA64L 12 1 C16 CAP, SANYO, 150μF, 16V, 20% SANYO, 16TSVPC150 13 1 D1 DIODE, POWER DI-123 DIODES/ZETEX, DFLS1100-7 14 1 L1 IND, 10μH, 7443631000 WÜRTH, 7443631000 15 1 Q1 SILICON N CHANNEL POWER MOSFET LFPAK RENESAS, RJK0651DPB 16 1 Q2 SILICON N CHANNEL POWER MOSFET LFPAK RENESAS, RJK0653DPB 17 1 RS1 RES, 0.003Ω 1W 1% 2512 PANASONIC ERJM1WSF3M0U 18 1 R1 RES, 2.2 1% 1/10W, 0603 VISHAY, CRCW06032R20FNEA 19 3 R2, R8, R10 RES, 0Ω 1% 1/16W, 0603 VISHAY, CRCW06030000Z0EA 20 2 R4, R20 RES, 100k 1% 1/16W, 0603 VISHAY, CRCW0603100KFKEA 21 1 R5 RES, 511k 1% 1/16W, 0805 VISHAY, CRCW0805511KFKEA 22 1 R6 RES, 30.1k 1% 1/10W, 0603 VISHAY, CRCW060330K1FKEA 23 1 R7 RES, 35.7k 1% 1/16W, 0603 VISHAY, CRCW060335K7FKEA 24 1 R13 RES, 100 1% 1/10W, 0603 VISHAY, CRCW0603100RFKEA 25 1 R14 RES, 1M 1% 1/10W, 0805 VISHAY, CRCW08051M00FKEA 26 1 R15 RES, 2Ω 1% 1/16W, 0603 VISHAY, CRCW06032R00FNEA 27 1 R16 RES, 57.6k 1% 1/16W, 0603 VISHAY, CRCW060357K6FKEA 28 1 R17 RES, 15.4k 1% 1/10W, 0603 VISHAY, CRCW060315K4FKEA 29 1 R18 RES, 1k 1% 1/16W, 0603 VISHAY, CRCW06031K00FKEA 30 1 U1 IC, LTC3891EUDC, QFN20EUDC-3X4 LINEAR TECHNOLOGY, LTC3891EUDC Additional Demo Board Circuit Components 1 R3, R9, R11, C11, R12, C18, C19, R19, R21 RES, 0603 OPT 2 C20, C21, C22 CAP, 7343 OPT 3 Q3, Q4 (OPT) MOSFET, LFPAK OPT Hardware 1 10 E1 TO E10 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 4 J1, J2, J3, J4 CONN, BANANA JACK, KEYSTONE-575-4 KEYSTONE 575-4 3 1 JP1 JMP, 3PIN 1 ROW, 0.079" SULLINS, NRPN031PAEN-RC 4 1 JP2 JMP, 3PIN 2 ROW, 0.079" SULLINS, NRPN032PAEN-RC 5 4 MTGS AT 4 CORNERS STANDOFF, NYLON 0.5 1/2" KEYSTONE, 8833(SNAP-ON) 6 2 XJP1, XJP2 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G dc1940af 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 VIN E8 JP1 RUN E5 E4 E3 E2 R20 100K E10 E9 C12 1K R18 5 3 6 4 JP2 MODE 1 2 FCM BURST PULSE SKIP 4.7nF 3. FOR SYNCHRONIZATION REMOVE JUMPER JP2 'MODE' AND CONNECT SOURCE OF THE SYNC SIGNAL TO TERMINALS E8 'SYNC' AND E9 'GND' 2. INSTALL SHUNTS AS SHOWN. 5 C14 47pF R17 R19 2.2 2 8 4 19 15 9 17 C18 OPT 4 INTVCC 15.4K OPT R21 OPT 18 1 16 C7 1uF R4 100k INTVCC 3 C11 OPT C9 0.1uF R12 OPT R11 OPT 63HVH56M SUN ELECT. C3 56uF/63V R8 0 VOUT + R1 3 R14 1 Meg 0805 OPT R9 C1 2.2uF 100V 1812 VIN 2 R16 57.6K VIN C2 2.2uF 100V 1812 1. ALL RESISTORS AND CAPACITORS ARE 0603 NOTES: GND GND J2 1 INTVCC SYNC OFF ON TRACK EXTVCC PGOOD GND GND 16 - 60V J1 E1 ILIM PLLIN/MODE PGND SGND SGND ITH RUN TRACK/SS EXTVCC PGOOD VIN LTC3891EUDC U1 C4 0.1uF 100V 2 R15 INTVCC INTVCC 4 C13 0.1uF 50V VIN Q2 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 2 OPT 4 C19 OPT 2 SCALE = NONE VICTOR K LT APPROVALS 4 Q1 1812 C10 2.2uF 100V R7 35.7K R5 511K 0805 R2 0 VOUT C5 10pF RJK0653DPB DFLS1100 RJK0651DPB 4 D1 C8 2.2pF 4.7uF 0805 C6 CUSTOMER NOTICE 13 11 10 12 6 5 14 7 20 30.1K R6 R3 OPT INTVCC LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. BG SW TG BOOST SENSE+ SENSE- INTVCC VFB FREQ 3 5 1 2 3 VIN SGND 21 5 1 2 3 4 5 1 2 3 VIN 5 OPT 1 C16 + 150uF 16V 16SVPC150M VOUT E7 J4 C17 1uF DATE: N/A LTC3891EUDC 1 SHEET 1 DEMO CIRCUIT 1940A Monday, March 26, 2012 IC NO. LOW QUIESCENT CURRENT HIGH VOLTAGE STEP-DOWN CONVERTER SIZE DATE VOUT VOUT 03-26-12 GND GND 12V / 15A J3 E6 VICTOR K. APPROVED OF 1 2 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only C15 10uF 1206 PRODUCTION DESCRIPTION REVISION HISTORY TECHNOLOGY OPT 7343 + 2512 10uH C22 C21 C20 RS1 0.003 L1 Q4 100 2 REV TITLE: SCHEMATIC Q3 0 R13 __ ECO R10 1 2 3 5 A B C D DEMO MANUAL DC1940A SCHEMATIC DIAGRAM dc1940af 5 DEMO MANUAL DC1940A 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 dc1940af 6 Linear Technology Corporation LT 0612 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2012