DEMO MANUAL DC1992A LT8620 65V, 2A Micropower Synchronous Monolithic Step-Down Regulator Description Demonstration circuit 1992A is a 65V, 2A micropower synchronous monolithic step-down regulator featuring the LT®8620. The LT8620 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 2.5µA of quiescent current when output is regulated at 5V. Top and bottom power switches, compensation components and other necessary circuits are inside of the LT8620 to minimize external components and simplify design. The SYNC pin on the demo board is grounded by default for low ripple Burst Mode® operation. To synchronous to an external clock, move JP1 to SYNC and apply the external clock to the SYNC turret. Once JP1 is on SYNC position, a DC voltage of higher than 2V or INTVCC can be applied to the SYNC turret pulse skipping operation. Figure 1 shows the efficiency of the circuit at 12V input. Performance Summary The demo board has an EMI filter installed. The board and the IC are designed to minimize conducted and radiated EMI. The radiated EMI performances of the board are shown on Figure 2 to Figure 4. The limits on those figures are CISPR25, Class 5 peak limits. It shows the circuit passes the test with a wide margin. The LT8620 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1992A. Design files for this circuit board are available at http://www.linear.com/demo/DC1992A L, LT, LTC, LTM, Linear Technology, Burst Mode 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 = 25°C SYMBOL PARAMETER VIN Input Supply Range CONDITIONS MIN 5.5 VOUT Output Voltage 4.8 IOUT Maximum Output Current fSW Switching Frequency EFE Efficiency at DC TYP 5 MAX V 5.2 V 2 1.85 IOUT = 1A UNITS 65 A 2 92 2.15 MHz % 100 95 EFFICIECNY (%) 90 85 80 75 70 65 60 0 0.5 1.0 1.5 LOAD CURRENT (A) 2.0 dc1992a F01 Figure 1. LT8620 12VIN to 5VOUT Efficiency at 2MHz Switching Frequency dc1992af 1 DEMO MANUAL DC1992A Description Figure 2. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A Antenna Polarization: Horizontal; Switching Frequency: 2MHz Figure 3. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A Antenna Polarization: Vertical; Switching Frequency: 2MHz Figure 4. 150kHz to 30MHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2A Antenna Polarization: Vertical; Switching Frequency: 2MHz (In the Frequency Range Between 150kHz and 30MHz, Only Vertical Polarization Is Required) dc1992af 2 DEMO MANUAL DC1992A Quick Start Procedure Demonstration circuit 1992A is easy to set up to evaluate the performance of the LT8620. Refer to Figure 5 and Figure 6 for proper measurement equipment setup and follow the procedure below: 2.With power off, connect the load VOUT and GND. 1.With power off, connect the input power supply to VIN and GND. 5.Carefully evaluate other design parameters as needed. 3.Check JP1 setting 4.Turn on the power at the input. Figure 5. Proper Measurement Equipment Setup Figure 6. Measure Output Ripple dc1992af 3 DEMO MANUAL DC1992A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C2 CAP., X7R, 2.2µF, 100V, 10%, 1206 MURATA, GRM31CR72A225K 2 1 C4 CAP., X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D 3 1 C5 CAP., C0G, 10pF, 25V, 10%, 0603 AVX, 06033A100KAT2A 4 1 C6 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE2015L 5 1 C7 CAP., X5R, 1.0µF, 10V, 10%, 0402 MURATA, GRM155R61A105K 6 1 C8 CAP., X7R, 0.1µF, 16V, 10%, 0603 MURATA, GRM188R71C104K 7 1 L1 IND, 2.2µH XFL4020 COILCRAFT, XFL4020-222MEC 8 1 R2 RES., CHIP, 18.2k, 1/10W, 1%, 0603 VISHAY, CRCW060318K2FKED 9 1 R3 RES., CHIP, 49.9k, 1/16W, 1%, 0603 VISHAY, CRCW060349K9FKED 10 2 R1, R4 RES., CHIP, 1M, 1/16W, 1%, 0603 VISHAY, CRCW06031M00FKED 11 1 R5 RES., CHIP, 243k, 1/16W, 1%, 0603 VISHAY, CRCW0603243KFKED 12 1 U1 IC, LT8620EMSE, MSE16 LINEAR TECH. CORP., LT8620EMSE#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM, 10µF, 100V SUN ELECT, 100CE10BS 2 2 C3, C10 CAP., X7S, 4.7µF, 100V, 10%, 1210 TDK, C3225X7S2A475K 3 1 C9 CAP., X7R, 1.0µF, 16V, 10%, 0805 AVX, 0805YC105KAT2A 4 2 C11, C12 CAP., X7R, 0.1µF, 100V, 10%, 0603 MURATA, GRM188R72A104K 5 1 C13 CAP., X5R, 0.1µF, 100V, 10%, 0402 MURATA, GRM155R62A104K 6 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S221A 7 1 L2 IND, 4.7µH IHLP2020BZ-01 VISHAY, IHLP2020BZ-ER4R7M01 8 0 R6 (OPT) RES., 0603 Hardware: For Demo Board Only 1 9 E1-E9 TESTPOINT, TURRET, 0.094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 3 PIN 0.079" SINGLE ROW HEADER SULLIN, NRPN031PAEN-RC 3 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 4 4 MH1-MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833(SNAP ON) dc1992af 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 GND VIN 5.5V - 65V E2 E1 5 TR/SS GND SYNC EN/UV C11 0.1uF 100V C3 4.7uF 100V 1210 GND SYNC C10 4.7uF 100V 1210 JP1 L2 4.7uH 3 2 1 10uF 100V SUNCON 100CE10BS + C1 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. 4 C7 1uF 0402 6.3V C2 2.2uF 100V 1206 NOTES: UNLESS OTHERWISE SPECIFIED E7 E9 E5 E6 C12 0.1uF 100V FB1 4 C8 0.1uF C13 0.1uF 100V 0402 R2 18.2k (2MHz) R6 OPT R1 1M 3 8 7 3 2 13 1 4 6 5 3 GND NC RT TR/SS INTVCC SYNC EN/UV VIN VIN U1 LT8620EMSE GND 17 D 5 FB PG BIAS SW SW SW BST 16 15 14 11 10 9 12 2 2 R5 243k C4 0.1uF 16V 0402 C5 49.9k 10pF 1Meg R4 R3 XFL4020-222MEC L1 2.2uH C6 47uF 10V 1210 VOUT 1 C9 1uF 16V 0805 1 E8 E4 E3 PG GND VOUT 5V / 2A A B C D DEMO MANUAL DC1992A Schematic Diagram dc1992af 5 DEMO MANUAL DC1992A 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 dc1992af 6 Linear Technology Corporation LT 0614 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014