DEMO MANUAL DC2137A LT8619 60V, 1.2A Synchronous Monolithic Buck Regulator with 6A Quiescent Current DESCRIPTION Demonstration circuit 2137A is a monolithic step-down DC/DC switching regulator featuring the LT(R)8619. The LT8619 is a high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 6A of quiescent current. The demo circuit is designed for 5V, 1.2A output from 6V to 48V input with the transient input voltage up to 60V. The wide input range makes it suitable for regulating power from a wide variety of sources, including automotive, industrial systems and telecom supplies. The power switch, compensation and other necessary circuits are inside of the LT8619 to minimize external components and simplify design. The LT8619 switching frequency can be programmed either via oscillator resistor or external clock over a 300kHz to 2.2MHz range. The default frequency of demo circuit 2137A is 2MHz. The SYNC pin on the demo board is grounded (JP1 at BURST position) by default for low ripple Burst Mode(R) operation. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC terminal. The RT resistor (R4) should be chosen to set the LT8619 internal switching frequency equal or below the lowest synchronization input. During clock synchronization, the controller enters forced continuous mode. Pulse-skipping mode and forced continuous mode can be selected respectively by moving JP1 shunt. PERFORMANCE SUMMARY SYMBOL PARAMETER VIN Input Supply Range VOUT Output Voltage fSW Switching Frequency IOUT Max Output Current EFE Efficiency at DC Low ripple Burst Mode operation increases the efficiency at the light load while keeping the output ripple low. Figure 1 shows the efficiency of the circuit at 12V and 24V input in Burst Mode operation (input from VIN terminal to bypass the EMI filter). The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown on Figure 2. The red line in Radiated EMI Performance 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 2, the input EMI filter is required and the input voltage should be applied at VEMI terminal. The LT8619 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 2137A. The LT8619 is assembled in a small 16-lead MSOP and 10-lead 3mm x 3mm DFN packages with exposed pad. Proper board layout is essential for both low EMI operation and maximum thermal performance. See the data sheet sections for details. Design files for this circuit board are available at http://www.linear.com/demo/DC2137A All registered trademarks and trademarks are the property of their respective owners. Specifications are at TA = 25C CONDITIONS MIN TYP 3 RT = 20k UNITS 60 V V 4.875 5 5.125 1.9 2 2.1 1.2 VIN = 12V, IOUT = 1.2A MAX MHz A 87.1 % UG-1297 Rev 0 1 DEMO MANUAL DC2137A DESCRIPTION 100 95 VIN = 12V EFFICIENCY (%) 90 85 VIN = 24V 80 75 70 fSW = 2MHz VOUT = 5V Burst Mode OPERATION 65 60 0 0.2 0.4 0.6 0.8 LOAD CURRENT (A) 1.0 1.2 DC2137A F01 DC2137A F02 Figure 1. LT8619 DC2137A Efficiency vs Load Current Figure 2. LT8619 DC2137A EMI Performance in CISPR25 Radiated Emission Test (12V Input from VEMI Turret Pin, IOUT = 1A) QUICK START PROCEDURE Demonstration circuit 2137A is easy to set up to evaluate the performance of the LT8619. Refer to Figure 3 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 4 for the proper scope technique. 1. Place JP1 on the Burst Mode operation position. 2. With power off, connect the input power supply to VIN1 and GND. Make sure that the input voltage does not exceed 60V. 3. With power off, connect loads from VOUT to GND. 4. Turn on the power at the input. 2 5. Check for the proper output voltage (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 voltages are 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/MODE position). Please make sure that R4 should be chosen to set the LT8619 switching frequency equal to or below the lowest SYNC frequency. See the data sheet Synchronization section. JP1 can also set LT8619 in pulse-skipping mode (JP1 on the PULSE-SKIPPING position) or forced continuous mode (JP1 on the FORCED CONTINUOUS position). DEMO MANUAL DC2137A Quick Start Procedure Figure 3. Proper Measurement Equipment Setup VOUT GND Figure 4. Measuring Input or Output Ripple UG-1297 Rev 0 3 DEMO MANUAL DC2137A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Demo Board Circuit Components 1 1 C2 CAP., X7R, 2.2F, 100V, 10% 1210 TDK, C3225X7R2A225K230AB 2 2 C5, C11 CAP., X7R, 1F, 25V, 10% 0603 TDK, C1608X7R1E105K080AB 3 1 C6 CAP., X7R, 0.1F, 25V, 10%, 0603 TDK, C1608X7R1E104K080AA 4 1 C8 CAP., C0G, 4.7pF, 50V, 0.25pF, 0603 MURATA, GRM1885C1H4R7CA01D 5 1 C10 CAP., X7R, 22F, 16V, 10% 1210 MURATA, GRM32ER71C226KE18L 6 1 L1 IND., 4.7H, XFL4030 COILCRAFT, XFL4030-472ME 7 2 R1, R5 RES., CHIP, 1M, 1/10W, 1% 0603 VISHAY, CRCW06031M00FKEA 8 1 R3 RES., CHIP, 100k, 1/10W, 1% 0603 VISHAY, CRCW0603100KFKEA 9 1 R4 RES., CHIP, 20k, 1/10W, 1% 0603 VISHAY, CRCW060320K0FKEA 10 1 R6 RES., CHIP, 191k, 1/10W, 1% 0603 VISHAY, CRCW0603191KFKEA 11 1 R7 RES., CHIP, 0, 1/10W, 0603 VISHAY, CRCW06030000Z0EA 12 1 U1 I.C., BUCK REGULATOR, MSOP-16E ANALOG DEVICES, LT8619EMSE#PBF Additional Demo Board Circuit Components 1 2 C12, 13 CAP., X7R, 2.2F, 100V, 10% 1210 TDK, C3225X7R2A225K230AB 2 2 C3, C4 CAP., X7R, 0.1F, 100V, 10% 0603 MURATA, GRM188R72A104KA35D 3 1 C1 CAP., ALUM. ELECTRO., 10F, 63V PANASONIC, EEHZC1J100P 4 1 FB BEAD, 330, MPZ2012 TDK, MPZ2012S331AT000 5 1 L2 IND., 2.2H, XEL4020 COILCRAFT, XEL4020-222ME 6 0 C7 CAP., 0603 (OPT) 7 0 R2 RES., CHIP, 0603 (OPT) Hardware/Components (for Demo Board Only) 1 2 E1, E2 TESTPOINT, TURRET, 0.061" PBF MILL-MAX, 2308-2-00-80-00-00-07-0 2 7 E3-E9 TESTPOINT, TURRET, 0.094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 3 1 JP1 0.079 x 4 DOUBLE ROW HEADER WURTH ELEKTRONIK, 62000821121 4 1 XJP1 SHUNT, 0.079" CENTER WURTH ELEKTRONIK, 60800213421 4 A B C D * PG EN E2 E1 E4 E3 C13 2.2uF 100V 1210 L2 2.2uH RT INTVCC R4 20K 1% (2MHz) 5 PG EN/UV NC Vin NC VIN 15 16 14 CUSTOMER NOTICE 7 C6 0.1uF L1 4.7uH XFL4030-472ME LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. SYNC 10 FB 9 FB SW SW BST BIAS 11 0 R6 191K 1% R5 1M 1% C8 4.7pF SYNC BURST C12 2.2uF 100V 1210 FB MPZ2012S331AT000 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 5 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. 4 XEL4020-222ME 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. DATE: N/A SIZE TECHNOLOGY 5 7 8 E9 SYNC E8 E7 C11 1uF 16V GND VOUT 5V / 1.2A 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 3 6 1 4 2 JP1 C10 22uF 16V 1210 VOUT 1 2 Thursday, September 28, 2017 1 SHEET 1 OF 1 60V, 1.2A, SYNCHRONOUS MONOLITHIC POWER BUCK REGULATOR IC NO. REV. LT8619EMSE 2 DEMO CIRCUIT 2137A TITLE: SCHEMATIC PULSE SKIPPING 1% C5 1uF 12 6 4 3 2 1 C7 OPT E6 VOUT R2 OPT R1 1M C4 0.1uF 100V U1 LT8619EMSE R7 2 FORCED CONTINUOUS R3 C2 2.2uF 100V 1210 C3 0.1uF 100V 3 E5 100K PANASONIC EEHZC1J100P 10uF 63V + C1 VIN NOTES: UNLESS OTHERWISE SPECIFIED GND VEMI GND VIN 6V - 60V SEE DEMO MANUAL GND 8 * GND 17 4 NC 13 5 A B C D DEMO MANUAL DC2137A SCHEMATIC DIAGRAM UG-1297 Rev 0 5 DEMO MANUAL DC2137A ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. 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