DEMO MANUAL DC2019B LT8614 42V, 4A Micropower Synchronous Step-Down Silent Switcher DESCRIPTION Demonstration circuit 2019B is a 42V, 4A micropower synchronous step-down Silent Switcher™ featuring the LT®8614. The demo board is designed for 5V output from a 5.8V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8614 is a compact, ultralow emission, high efficiency and high speed synchronous monolithic step-down switching regulator. The integrated power switches and inclusion of all necessary circuitry reduce the components count and solution size. Special Silent Switcher architecture minimizes EMI/EMC emissions. Ultralow 2.5µA quiescent current in Burst Mode® operation achieves high efficiency at very light loads. Fast minimum on-time of 30ns enables high VIN to low VOUT conversion at high frequency. The LT8614 switching frequency can be programmed either via oscillator resistor or external clock over a 200kHz to 3MHz range. 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 3V can be applied to the SYNC turret for pulse-skipping operation. Figure 1 shows the efficiency of the circuit at 12V input in Burst Mode operation (input from VIN turret pin). Figure 2 shows the LT8614 temperature rising on DC2019B demo board under different load conditions. The rated maximum load current is 4A, while derating is necessary for certain VIN and thermal conditions. The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown in Figure 3. The red line in Figure 3 is CISPR25 Class 5 peak limit. The figure shows that the circuit passes the test with a wide margin. To achieve EMI/EMC performance as shown in Figure 3, the input EMI filter is required and the input voltage should be applied at VEMI turret pin. The LT8614 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo manual for demo circuit 2019B. The LT8614 is assembled in a 3mm × 4mm plastic QFN package with exposed pads for low thermal resistance. Proper board layout is essential for both low EMI operation and maximum thermal performance. See the data sheet sections, “Low EMI PCB Layout” and “High Temperature Considerations.” Design files for this circuit board are available at http://www.linear.com/demo/DC2019B L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and Silent Switcher is a trademark 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 VOUT Output Voltage IOUT Maximum Output Current fSW Switching Frequency EFE Efficiency at DC MIN TYP 5.8 4.85 Derating is Necessary for Certain VIN and Thermal Conditions 42 5 5.15 4 1.85 VIN = 12V, IOUT = 3A MAX UNITS V V A 2 91.3 2.15 MHz % dc2019bfb 1 DEMO MANUAL DC2019B PERFORMANCE 100 95 VOUT = 5V 90 fSW = 2MHz 90 80 TEMPERATURE RISING (°C) EFFICIENCY (%) 100 85 80 75 70 VIN = 12V VOUT = 5V fSW = 2MHz 65 60 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 3.5 60 50 40 30 20 10 4 12 6 18 24 30 36 42 INPUT VOLTAGE (V) IOUT = 4A IOUT = 2.5A IOUT = 3.5A IOUT = 2A dc2019a F02 IOUT = 3A dc2019a F01 Figure 2. Temperature Rising vs Input Voltage Figure 1. Efficiency vs Load Current (Input from VIN Turret Pin) 50 70 DETECTOR: +PEAK AMPLITUDE (dBµV/m) 40 30 20 10 CLASS 5 PEAK DATA 0 0 100 200 300 400 600 500 FREQUENCY (MHz) 700 800 900 1000 dc2019a F03 Figure 3. LT8614 Demo Circuit EMI Performance in CISPR25 Radiated Emission Test (14V Input from VEMI Turret Pin, IOUT = 4A) dc2019bfb 2 DEMO MANUAL DC2019B QUICK START PROCEDURE Demonstration circuit 2019B is easy to set up to evaluate the performance of the LT8614. Refer to Figure 4 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 VEMI or VOUT and GND terminals. See Figure 5 for the proper scope technique. 1. Place JP1 on GND position. 2. With power off, connect the input power supply to VEMI and GND. If the EMI/EMC performance is not important, the input EMI filter can be bypassed by connecting the input power supply to VIN and GND. 5. Check for the proper output voltage (VOUT = 5V). NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high or is shorted. 6. Once the proper output voltage is established, adjust the load within the operating ranges and observe the output voltage regulation, ripple voltage, efficiency and other parameters. 7. An external clock can be added to the SYNC terminal when SYNC function is used (JP1 on the SYNC position). Please ensure that the chosen RT sets the LT8614 switching frequency to equal or below the lowest SYNC frequency. See the data sheet section, “Synchronization.” 3. With power off, connect the load from VOUT to GND. 4. Turn on the power at the input. NOTE: Make sure that the input voltage does not exceed 42V. Figure 5. Measuring Output Ripple Figure 4. Proper Measurement Equipment Setup dc2019bfb 3 DEMO MANUAL DC2019B PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C2, C12 CAP., X5R, 1µF, 50V, 10%, 0603 TDK, C1608X5R1H105K 2 2 C4,C8 CAP., X7R, 0.1µF, 16V, 10%, 0603 MURATA, GRM188R71C104KA01D 3 1 C5 CAP., C0G, 4.7pF, 25V, ±0.25p, 0603 AVX, 06033A4R7CAT2A 4 1 C6 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L 5 2 C7, C13 CAP., X7R, 1µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D 6 1 C9 CAP., X5R, 4.7μF, 25V, 10%, 0603 MURATA, GRM188R61E475KE11D 7 1 C11 CAP., X5R, 10µF, 50V, 10%, 1206 MURATA, GRM31CR61H106KA12L 8 1 L1 IND, 1.5µH, IHLP2020CZ-01 VISHAY, IHLP2020CZER1R5M01 9 2 R1, R3 RES., CHIP, 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA 10 1 R2 RES., CHIP, 18.2k, 1/10W, 1%, 0603 VISHAY, CRCW060318K2FKEA 11 1 R4 RES., CHIP, 1M, 1/10W, 1%, 0603 VISHAY, CRCW06031M00FKEA 12 1 R5 RES., CHIP, 243k, 1/10W, 1%, 0603 VISHAY, CRCW0603243KFKEA 13 1 U1 IC, REGULATOR, 20-QFN, UDC LINEAR TECHNOLOGY, LT8614EUDC#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM, 22µF, 63V SUN ELECT., 63CE22BS 2 1 C3 CAP., X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 3 1 C10 CAP., X7R, 10µF, 50V, 10%, 1210 MURATA, GRM32ER71H106KA12L 4 1 C14 CAP., X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K 5 1 FB1 CHIP BEAD, MPZ2012 TDK, MPZ2012S300AT 6 1 L2 IND., 0.22µH,IHLP1616AB-01 VISHAY, IHLP1616ABERR22M01 7 0 R6 (OPT) RES., 0603 8 1 R7 RES., CHIP, 0, 1/10W, 0603 VISHAY, CRCW06030000Z0EA Hardware: For Demo Board Only 1 10 E1-E10 TESTPOINT, TURRET, 0.094" pbf MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 HEADER, 3 PIN, 0.079", SINGLE ROW SULLINS, 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) dc2019bfb 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. SCHEMATIC DIAGRAM DEMO MANUAL DC2019B dc2019bfb 5 DEMO MANUAL DC2019B 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 dc2019bfb 6 Linear Technology Corporation LT 0515 REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013