DEMO MANUAL DC2172A LTC7138 High Efficiency, High VIN, Step-Down Regulator Description Demonstration circuit 2172A is a high input voltage, 400mA step-down regulator featuring the LTC7138. The output of the regulator can be programmed for either 5V, 3.3V or 1.8V with on-board jumpers or is adjustable from 800mV to VIN using an optional feedback divider. The input voltage range is from 4V to 140V. The LTC7138’s Burst Mode® operation, low quiescent current and internal top FET switch provide high efficiency over a wide range of loads. Other features include: • Optional components to adjust the current limit, make it proportional to VIN or improve the efficiency and reduce the output voltage ripple. • FBO turret to tie two or more LTC7138 regulators together if the application requires more load current. • Optional UVLO and OVLO divider. • External/internal soft-start. For more details, refer to the LTC7138 data sheet. The LTC7138 data sheet gives a complete description of the IC operation and application information. The data sheet must be read in conjunction with this quick start guide. Design files for this circuit board are available at http://www.linear.com/demo/DC2172A 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. Performance Summary Specifications are at TA = 25°C PARAMETER CONDITIONS Input Voltage Range VALUE 4V to 140V 5.0V Output Voltage VIN = 12V, IOUT = 0mA to 400mA 5.0V ±2% 3.3V Output Voltage VIN = 12V, IOUT = 0mA to 400mA 3.3V ±2% 1.8V Output Voltage VIN = 12V, IOUT = 0mA to 400mA 1.8V ±2% Maximum Output Current, IOUT VIN = 4V to 140V, VOUT = 5.0, 3.3V, 1.8V or ADJ (VOUT ≤ VIN) 400mA Typical Efficiency VIN = 12V, VOUT = 5V, IOUT = 400mA 82.3% Typical Output Ripple VIN = 12V, VOUT = 5V, IOUT = 400mA 87mVP-P dc2172af 1 DEMO MANUAL DC2172A Quick Start Procedure Demonstration circuit 2172A is easy to set up to evaluate the performance of the LTC7138. Please refer to Figure 1 for proper measurement equipment setup and follow the procedure below. Note 1. CAUTION: The maximum input voltage of the DC2172A is 140V. Voltages of 140V or lower are high enough to cause electric shock. Use great care when testing this demo board. 1)With power off, connect the input supply, load and meters as shown in Figure 1. Preset the load to 0A and VIN supply to 0V. Note 2. For a 5V output, the input voltage should be 6V or more. 2)Place the RUN pin jumper (JP3) in the ON position. 3)Set the output to 5V by placing the JP1 jumper in the B position and the JP2 jumper in the A position. 4)Turn-on the VIN supply and increase to 12V. The 5V output should be 5V ±2% per the Performance Summary table. Note 3. When measuring the output or input voltage ripple, do not use the long ground lead on the oscilloscope probe. See Figure 2 for the proper scope probe technique. Short, stiff leads need to be soldered to the (+) and (–) terminals of an output capacitor. The probe’s ground ring needs to touch the (–) lead and the probe tip needs to touch the (+) lead. 5)Next, apply 400mA load to the output and re-measure VOUT. 6)Once the DC regulation is confirmed, observe the output voltage ripple, load step response, efficiency and other parameters for the 5V, 3.3V and 1.8V output settings. 2 dc2172af DEMO MANUAL DC2172A Quick Start Procedure IIN IOUT + VIN SUPPLY VOUT LOAD + – – Figure 1. Proper Measurement Equipment Setup + VOUT – COUT GND Figure 2. Measuring Output Voltage Ripple dc2172af 3 DEMO MANUAL DC2172A Quick Start Procedure 90 80 70 L = Sumida CDRH105RNP-151NC (150µH, DCR = 285mΩ typ) VOUT = 5V Efficiency (%) 60 50 40 30 20 12VIN 48VIN 100VIN 140VIN 10 0 0.01 0.10 1 10 Load Current (mA) 100 1,000 dc2172a F03 Figure 3. Efficiency at 5VOUT 80 70 L = Sumida CDRH105RNP-151NC (150µH, DCR = 285mΩ typ) VOUT = 3.3V Efficiency (%) 60 50 40 30 20 12VIN 48VIN 100VIN 140VIN 10 0 0.01 0.10 1 10 Load Current (mA) 100 1,000 dc2172a F04 Figure 4. Efficiency at 3.3VOUT 4 dc2172af DEMO MANUAL DC2172A Quick Start Procedure 70 60 L = Sumida CDRH105RNP-151NC (150µH, DCR = 285mΩ typ) VOUT = 1.8V Efficiency (%) 50 40 30 20 12VIN 48VIN 100VIN 140VIN 10 0 0.01 0.10 1 10 Load Current (mA) 100 1,000 dc2172a F05 Figure 5. Efficiency at 1.8VOUT dc2172af 5 DEMO MANUAL DC2172A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 CAP 22µF, 200V, ELEC NIPPON CHEMI-CON, EMVE201ARA220MKG5S 2 1 C2 CAP 1µF, 2220, 10%, 200V, X7R KEMET C2220X105K2RACTU 3 1 C4 CAP 47nF, 0603, 10%, 25V, X7R AVX 06033C473KAT2A 4 2 C6, C7 CAP 100µF, 1210, 20%, 10V, X7R TAIYO YUDEN LMK325ABJ107MMH-T 5 1 C9 CAP 0.1µF, 0603, 10%, 25V, X7R AVX 06033C104KAT2A 6 1 D1 DIODE SBR1U200P1 DIODES, SBR1U200P1-7 7 1 L1 INDUCTOR 150µH SUMIDA CDRH105RNP-151NC 8 1 R1 RES 2M, 0603Ω, 5%, 1/10W VISHAY CRCW06032M00JNEA 9 1 U1 IC LTC7138EMSE LINEAR TECH LTC7138EMSE#PBF Additional Demo Board Circuit Components 1 0 C3 CAP 0603 OPTION OPTION 2 0 C8, C10 CAP 1210 OPTION OPTION 3 0 R2, R4, R7, R8 RES 0603 OPTION OPTION 4 2 R3, R6 RES 0Ω 0603 JUMPER VISHAY CRCW06030000Z0ED 1 5 E1, E2, E3, E4, E5 TURRET MILL-MAX 2501-2-00-80-00-00-07-0 2 3 JP1, JP2, JP3 HEADER 2mm PIN SULLINS, NRPN031PAEN-RC 3 4 MH1, MH2, MH3, MH4 STANDOFF SNAP ON KEYSTONE_8831 4 3 JP1, JP2, JP3 SHUNT 2mm SAMTEC 2SN-BK-G Hardware 6 dc2172af 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 E5 C1 22uF + 200V VIN R3 0 R2 OPT R1 2M VIN ON 1 RUN OPT R8 2 [3] B A 5.0V EXT. R 5 B A 3.3V JP1 1.8V VOUT A A B B JP2 3 11 5 12 14 C3 OPT C2 1uF 200V 2220 ISET FBO OVLO RUN VIN SW 3 6 7 10 9 16 1 4 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. L1 150uH APPROVALS SCALE = NONE 1 2 3 1 2 3 JP2 [3] JP1 [3] A B A B 2 DATE: N/A SIZE VOUT C8 C10 OPT 1210 2 E3 GND VOUT C9 1.8V / 3.3V / 5V 0.1uF 400mA E2 1 SHEET 1 HIGH EFFICIENCY, HIGH VIN, 400mA STEP-DOWN REGULATOR LTC7138EMSE DEMO CIRCUIT 2172A TECHNOLOGY 2 OF 1 RE V . 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only Tuesday, January 06, 2015 IC NO. C6 C7 100uF 10V 1210 1 4. SMALLER AMOUNT OF COUT CAN BE USED FOR APPLICATIONS THAT CAN TOLERATE HIGHER OUPUT RIPPLE. REFER TO THE DATA SHEET FOR APPLICATIONS INFORMATION. R7 OPT R6 0 TITLE: SCHEMATIC D1 SBR1U200P1 CDRH105R C4 47nF 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 APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. VPRG2 VPRG1 SS VFB ANODE LTC7138EMSE U1 CUSTOMER NOTICE R4 OPT 2. FOR 5V OUTPUT, VIN RANGE IS 6V-140V. 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. JP3 OFF 3 NOTE: UNLESS OTHERWISE SPECIFIED FB0 GND E4 4V - 140V VIN E1 4 NC NC NC NC 2 4 13 15 GND 8 GND 17 5 A B C D DEMO MANUAL DC2172A Schematic Diagram dc2172af 7 DEMO MANUAL DC2172A 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 8 dc2172af Linear Technology Corporation LT 0115 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2015