DEMO MANUAL DC2139A LT8610A 42V, 3.5A Micropower Synchronous Step-Down Regulator Description Demonstration circuit 2139A is a 42V, 3.5A micropower synchronous step-down regulator featuring the LT®8610A. The LT8610A 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 and is unloaded. The 2139A uses two input ceramic capacitors in series to improve reliability in case of an input capacitor short failure. Top and bottom power switches, compensation components and other necessary circuits are inside of the LT8610A to minimize external components and simplify design. output current and 2MHz switching frequency, the temperature rise will be significant. Either reducing the input voltage, the output current or the switching frequency will bring the temperature down to acceptable level without external cooling. The SYNC pin on the demo board is grounded by default for low ripple burst mode operation. To synchronize 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 for pulse-skipping operation. Figure 1 shows the efficiency of the circuit at 12V input. The LT8610A 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 2139A. Figure 2 shows the thermal performance of the circuit. When running at input voltage greater than 30V, 3.5A 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 in Figure 3 to Figure 5. The limits on those figures are CISPR25, Class 5 peak limits. The circuit passes the test with a wide margin. Design files for this circuit board are available at http://www.linear.com/demo 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. Performance Summary Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS VIN* Input Supply Range 5.5 VOUT Output Voltage 4.8 IOUT Maximum Output Current 3.5 FSW Switching Frequency EFE Efficiency at DC MIN 1.85 IOUT = 1A TYP MAX UNITS 42 V 5 5.2 V A 2 92 2.15 MHz % *Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching frequency. dc2139af 1 DEMO MANUAL DC2139A Quick Start Procedure Demonstration circuit 2139A is easy to set up to evaluate the performance of the LT8610A. Refer to Figure 6 and Figure 7 for proper measurement equipment setup and follow the procedure below: 1.With power off, connect the input power supply to VIN and GND. When evaluating EMI performance, input power supply should be connected between VEMI and GND. 2.With power off, connect the load VOUT and GND. 3.Check JP1 setting 4.Turn on the power at the input. 5.Carefully evaluate other design parameters as needed. 100 95 EFFICIENCY (%) 90 85 80 75 70 65 60 0 1 2 LOAD CURRENT (A) 3 DC2139a F01 Figure 1. LT8610A 12VIN to 5VOUT Efficiency at 2MHz Switching Frequency CASE TEMPERATURE RISE (°C) 140 TA = 25°C fSW = 2MHz ILOAD = 3.5A 120 100 80 60 40 20 0 fSW = 2MHz ILOAD = 2.5A 8 12 fSW = 1MHz ILOAD = 3.5A 20 28 16 24 INPUT VOLTAGE (V) 32 36 DC2139a F02 Figure 2. LT8610A Case Temperature Rise, VOUT = 5V, TA = 25°C dc2139af 2 DEMO MANUAL DC2139A Quick Start Procedure Figure 3. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A Antenna Polarization: Horizontal; Switching Frequency: 2MHz. Figure 4. 30MHz to 1GHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A Antenna Polarization: Vertical; Switching Frequency: 2MHz. dc2139af 3 DEMO MANUAL DC2139A Quick Start Procedure Figure 5. 150kHz to 30MHz Radiated EMI Performance. VIN = 12V, VOUT = 5V, IOUT = 2.5A Antenna Polarization: Vertical; Switching Frequency: 2MHz. (In the frequency range between 150kHz and 30MHz, only vertical polarization is required) dc2139af 4 DEMO MANUAL DC2139A Quick Start Procedure Figure 6. Proper Measurement Equipment Setup Figure 7. Measure Output Ripple dc2139af 5 DEMO MANUAL DC2139A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C2, C19 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 2 2 C4, C8 CAP, X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D 3 1 C5 CAP, C0G, 4.7pF, 25V, ±0.1pF, 0402 MURATA, GRM1555C1E4R7BZ01D 4 1 C6 CAP, X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L 5 1 C7 CAP, X5R, 1µF, 10V, 10%, 0402 MURATA, GRM155R61A105K 6 1 L1 IND, 2.2UH COILCRAFT, XAL5030-222MEC 7 2 R1, R4 RES, CHIP, 1M, 1/16W, 1% 0402 NIC, NRC04F1004TRF 8 1 R2 RES, CHIP, 18.2k, 1/10W, 1% 0603 VISHAY, CRCW060318K2FKED 9 1 R3 RES, CHIP, 49.9k, 1/16W, 1% 0402 VISHAY, CRCW040249K9FKED 10 1 R5 RES, CHIP, 243k, 1/16W, 1% 0402 VISHAY, CRCW0402243KFKED 11 1 U1 IC, LT8610AEMSE MSE16 LINEAR TECHNOLOGY CORPORATION, LT8610AEMSE#PBF Additional Demo Board Circuit Components 1 1 C1 CAP, ALUM, 22µF, 63V SUN ELECT, 63CE22BS 2 4 C3, C10, C18, C20 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 3 1 C9 CAP, X7R, 1µF, 16V, 10%, 0805 AVX, 0805YC105KAT2A 4 6 C11, C12, C13, C15, C16, C17 CAP, X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K 5 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S101AT 6 1 L2 IND 4.7UH VISHAY, IHLP2020BZ-ER4R7M01 7 0 R6 RES, OPT, 0402 OPT Hardware: For Demo Board Only 1 10 E1 TO E10 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 SAMTEC, TMM103-02-L-S 3 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 4 4 MH1 TO MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833(SNAP ON) dc2139af 6 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 * GND * VEMI 5.5V - 42V E2 E1 E10 5 E7 E9 E5 GND JP1 C18 4.7uF 50V 1206 C20 4.7uF 50V 1206 SYNC C10 4.7uF 50V 1206 C3 4.7uF 50V 1206 L2 4.7uH 3 2 1 22uF 63V SUNCON 63CE22BS + C1 4 * REFER TO THE DEMO MANUAL FOR VIN RANGE. 1. ALL RESISTORS ARE 0402. ALL CAPACITORS ARE 0402. NOTES: UNLESS OTHERWISE SPECIFIED TR/SS GND SYNC E6 C16 0.1uF 50V C15 0.1uF 50V EN/UV C12 0.1uF 50V C11 0.1uF 50V FB1 4 C7 1uF 10V C19 4.7uF 50V 1206 C2 4.7uF 50V 1206 C8 0.1uF C17 0.1uF 50V C13 0.1uF 50V R2 18.2k (2MHz) 0603 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 FB PG BIAS SW SW SW BST U1 LT8610AEMSE GND 17 VIN 5.5V - 42V 5 16 15 14 11 10 9 12 2 R5 243k C4 0.1uF 10V 2 C5 49.9k R3 4.7pF 1Meg R4 XAL5030-222MEC L1 2.2uH C6 47uF 10V 1210 VOUT 1 1 C9 1uF 16V 0805 E8 E4 E3 PG GND VOUT 5V / 3.5A A B C D DEMO MANUAL DC2139A Schematic Diagram dc2139af 7 DEMO MANUAL DC2139A 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 dc2139af 8 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