DEMO MANUAL DC1869A LT3667 40V Step-Down Regulator with Dual LDOs Description Demonstration circuit 1869A is a triple power supply including one 400mA step-down regulator and two 200mA low dropout linear regulators (LDOs) featuring the LT®3667. The demo circuit is designed for 5.0V, 3.3V and 2.5V outputs from a 6V to 40V input. Two LDO outputs are configured as post-regulators of the switching regulator output. The total current capability of three output channels is up to 400mA in this configuration, while the two LDO regulators are capable of 200mA each. The LT3667 internal boost diode and loop compensation reduce the components count and solution size. The current mode control scheme creates fast transient response and good loop stability. The switching regulator has cycleby-cycle current limit and diode current sense, providing protection against shorted outputs. The switching frequency of the step-down regulator can be programmed either via a oscillator resistor over a 250kHz to 2.2MHz range or an external clock over a 300kHz to 2.2MHz range. When the circuit is synchronized to an external clock connected to the SYNC terminal, the RT resistor (R8) should be chosen to set the LT3667 internal switching frequency at least 20% below the final SYNC frequency. The LT3667 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 DC1869A. Proper board layout is essential for both proper operation and maximum thermal performance. See the PCB Layout section in the data sheet. JP1 can be used to set the whole LT3667 in shutdown mode. JP3 and JP4 enable and disable the 2.5V LDO output and 3.3V LDO output respectively. Design files for this circuit board are available at http://www.linear.com/demo/DC1869A 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 SYMBOL PARAMETER VIN1 Input Supply Range of VIN1 fSW Switching Frequency VOUT1 Specifications are at TA = 25°C CONDITIONS MIN TYP MAX UNITS 6 40 V VIN1 = 12V, VOUT1 = 5V/IOUT1 = 400mA VOUT2 = 2.5V/IOUT2 = 0mA VOUT3 = 3.3V/IOUT3 = 0mA 510 690 kHz Output Voltage 1 VIN1 = 12V, VOUT1 = 5V/IOUT1 = 0mA to 400mA VOUT2 = 2.5V/IOUT2 = 0mA VOUT3 = 3.3V/IOUT3 = 0mA 4.9 5.1 V VOUT2 Output Voltage 2 VIN1 = 12V, VOUT1 = 5V/IOUT1 = 0mA VOUT2 = 2.5V/IOUT2 = 0mA to 190mA VOUT3 = 3.3V/IOUT3 = 0mA 2.43 2.57 V VOUT3 Output Voltage 3 VIN1 = 12V, VOUT1 = 5V/IOUT1 = 0mA VOUT2 = 2.5V/IOUT2 = 0mA VOUT3 = 3.3V/IOUT3 = 0mA to 190mA 3.21 3.39 V IOUT1 + IOUT2 + IOUT3 Maximum Total Output Current IN2 and IN3 are powered by VOUT1 400 IOUT2, IOUT3 Maximum LDO Output Current 190 mA 200 mA dc1869af 1 DEMO MANUAL DC1869A Quick Start Procedure 90 80 VIN1 = 24V EFFICIENCY (%) 70 VIN1 = 12V 60 50 40 30 VOUT1 = 5V fSW = 600kHz IOUT2 = 0 IOUT3 = 0 20 10 0 0 0.1 0.2 0.3 LOAD CURRENT (A) 0.4 DC1869A F01 Figure 1. VOUT1 Typical Efficiency vs Load Current + VIN1 – + + – – – VOUT2 VOUT1 + – + – + – LOAD + – + – LOAD + VOUT3 – + – + – + LOAD Figure 2. Proper Measurement Equipment Setup 2 dc1869af DEMO MANUAL DC1869A Quick Start Procedure Demonstration circuit 1869A is easy to set up to evaluate the performance of the LT3667. Refer to Figure 2 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 3 for the proper scope technique. 1.Place JP1, JP3 and JP4 on the EN position. Place JP2 on the RT position. 2.With power off, connect the input power supply to VIN1 and GND. 3.With power off, connect loads from VOUT1 to GND, from VOUT2 to GND, and from VOUT3 to GND. 4.Turn on the power at the input. NOTE: Make sure that the input voltage do not exceed 40V. 5.Check for the proper output voltages: VOUT1 = 5V, VOUT2 = 2.5V, VOUT3 = 3.3V NOTE. If there is no output, temporarily disconnect the load to make sure that the loads are not set too high or are shorted. 6.Once the proper output voltages are established, adjust the loads 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 (JP2 on the SYNC position). Please make sure that RT should be set to provide a frequency at least 20% below the final SYNC frequency. See the Synchronization section in the data sheet. Figure 3. Measuring Input or Output Ripple dc1869af 3 DEMO MANUAL DC1869A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C2 CAP., X7S 2.2µF 100V 20% 1206 TDK C3216X7S2A225M 2 1 C3 CAP., X7R 0.22µF 25V 10% 0603 AVX 06033C224KAT2A 3 1 C4 CAP., NPO 22pF 25V 5% 0603 AVX 06033A220JAT2A 4 1 C5 CAP., X5R 22µF 10V 20% 0805 TAIYO YUDEN LMK212BJ226MG-T 5 2 C7, C11 CAP., X7R 4.7µF 10V 10% 0805 TAIYO YUDEN LMK212B7475KG-T 6 2 C9, C10 CAP., X5R 1µF 16V 10% 0603 TAIYO YUDEN EMK107BJ105KA-T 7 1 D1 SCHOTTKY DIODE 1A/60V POWERDITM123 DIODES INC. DFLS160-7 8 1 L1 INDUCTOR, 22µH SUMIDA CDRH4D22HPNP-220MC 9 1 R1 RES., CHIP 1M 0.10W 5% 0603 VISHAY CRCW06031M00JNEA 10 4 R3, R5, R11, R16 RES., CHIP 150k 0.10W 5% 0603 VISHAY CRCW0603150KJNEA 11 1 R7 RES., CHIP 931k 0.10W 1% 0603 VISHAY CRCW0603931KFKEA 12 1 R8 RES., CHIP 174k 0.10W 1% 0603 VISHAY CRCW0603174KFKEA 13 1 R9 RES., CHIP 294k 0.10W 1% 0603 VISHAY CRCW0603294KFKEA 14 1 R13 RES., CHIP 340k 0.10W 1% 0603 VISHAY CRCW0603340KFKEA 15 2 R14, R17 RES., CHIP 158k 0.10W 1% 0603 VISHAY CRCW0603158KFKEA 16 1 R15 RES., CHIP 499k 0.10W 1% 0603 VISHAY CRCW0603499KFKEA 17 1 U1 I.C., VOLTAGE REG. QFN(24) (UDD) 3mm × 5mm LINEAR TECH. CORP. LT3667EUDD#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM 10µF 63V 20% OSCON-CE-6.3 SUN ELECTRONIC INDUSTRIES 63CE10GA 2 1 C6 CAP., X7R 0.1µF 16V 10% 0603 AVX 0603YC104KAT2A 3 0 C8, C12 (OPT) CAP., 0603 4 2 C13, C14 CAP., X7R 47nF 25V 20% 0603 5 0 C15, C16 (OPT) CAP., 1206 6 0 C17 (OPT) CAP., X7R 10pF 25V 10% 0603 AVX 06033C100KAT2A 7 0 FB1 (OPT) FERRITE BEAD, 600Ω/500mA 0603 TDK MMZ1608S601AT 8 0 L2 (OPT) INDUCTOR, 4.7µH SUMIDA CDRH2D18/LDNP-4R7NC 9 3 R2, R6, R18 RES./JUMPER, CHIP 0Ω 0.1W 5A 0603 VISHAY CRCW06030000Z0EA 10 0 R4 (OPT) RES., 0603 11 2 R10, R12 RES., CHIP 1.50k 0.10W 1% 0603 VISHAY CRCW06031K50FKEA 12 1 R19 RES., CHIP 200k 0.10W 1% 0603 VISHAY CRCW0603200KFKEA 13 1 R20 RES., CHIP 100k 0.10W 1% 0603 VISHAY CRCW0603100KFKEA 14 0 R21 (OPT) RES., CHIP 10k 0.10W 5% 0603 VISHAY CRCW060310K0JNEA AVX 06033C473MAT2A Hardware: For Demo Board Only 4 1 17 E1-E17 TURRET, TESTPOINT MILL-MAX 2501-2-00-80-00-00-07-0 2 4 JP1, JP2, JP3, JP4 HEADERS, 3 PINS 2mm CTRS. SULLINS NRPN031PAEN-RC 3 4 XJP1, XJP2, XJP3, XJP4 SHUNT, 2mm CTRS. SAMTEC 2SN-BK-G 4 4 MH1, MH2, MH3, MH4 STAND-OFF, NYLON 0.25" TALL KEYSTONE 8831(SNAP ON) dc1869af 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 EN DIS DIS EN 3 2 1 3 2 1 VIN1_EMI JP3 EN2 JP1 ENABLE MMZ1608S601AT 0603 (OPT) 3 2 1 10pF (OPT) C17 174k 1% fs=600kHz 10k (OPT) 47nF C14 1.50k 1% 4.7uH C16 CDRH2D18/LDNP-4R7NC Sumida 1206 (OPT) (OPT) L2 + C1 10uF 63V R8 R21 R12 150k R5 100k 1% 200k 1% JP4 EN3 3 2 1 EN DIS JP2 R20 FB1 E7 E5 MODE R19 RT SYNC SYNC PG GND 5 * 4 1. ALL RESISTORS 0603. 2. ALL CAPACITORS 0603. SEE DEMO MANUAL FOR CURRENT CAPABILITY. NOTE: UNLESS OTHERWISE SPECIFIED. C15 1206 (OPT) E15 47nF C13 1.50k 1% R10 E8 C2 2.2µF 100V 1206 EN3/ILIM3 R17 158k 1% R15 499k 1% 13 14 11 15 10 23 24 L1 22uH R14 158k 1% C9 1µF 16V R18 340k 1% R13 0 Ohm R6 IN2 0 Ohm D1 DFLS160-7 CDRH4D22HPNP-220MC R9 294k 1% 0.22µF CUSTOMER NOTICE C10 1µF 16V IN3 FB2 R2 0 Ohm C3 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. C:\PADS PROJECTS\1869A(LT3776EUDD)\SCH\1869A_08_REV3.DSN 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. C11 4.7µF 10V 0805 PG2 IN2 FB1 DA SW OUT2 EN2/ILIM2 SYNC RT PG EN 21 22 NC NC 17 16 2 4 18 3 (OPT) R4 R1 1M 19 UVLO1 GND 25 20 IN1 FB3 8 E1 VIN1 6V TO 40V TRANSIENT TO 60V E3 GND OUT3 7 D 9 PG1 3 1 BOOST IN3 6 4 5 BD PG3 12 5 C7 4.7µF 10V 0805 2 SCALE = NONE APP ENG. PCB DES. E14 E13 E12 E17 E11 E10 E9 E16 E6 E4 * GND VOUT3 3.3V / 200mA PG3 IN3 GND VOUT2 2.5V / 200mA PG2 IN2 GND VOUT1 5V / PG1 www.linear.com C12 TBD R16 150k C8 TBD R11 150k C6 0.1µF 16V R3 150k E2 1 MODIFY DATE: IC NO. 17:00:05 1 SHEET 1 OF 3 1 REV. 40V STEP-DOWN REGULATOR WITH DUAL LDOS SIZE TECHNOLOGY TITLE: SCHEMATIC C5 22µF 10V 0805 APPROVALS 931k 1% 22pF R7 C4 2 A B C D DEMO MANUAL DC1869A Schematic Diagram dc1869af 5 DEMO MANUAL DC1869A 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 6 dc1869af Linear Technology Corporation LT 0914 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014