DEMO MANUAL DC1895A LTC3633A Dual Channel 3A 20V Monolithic Synchronous Step-Down Regulator Board Description Demonstration circuit DC1895 is a dual output regulator consisting of two constant-frequency step-down converters, based on the LTC3633A monolithic dual channel synchronous buck regulator. The DC1895 has an input voltage range of 3.6V to 20V, with each regulator capable of delivering up to 3A of output current. The DC1895 can operate in either Burst Mode® operation or forced continuous mode. In shutdown, the DC1895 can run off of less than 15µA total. The DC1895 is a very efficient circuit: over 90% for either circuit. The DC1895 uses the 28-Pin QFN LTC3633AEUFD package, which has an exposed pad on Performance Summary PARAMETER Minimum Input Voltage Maximum Input Voltage Run Output Voltage VOUT1 Typical Output Ripple VOUT1 Output Regulation VOUT1 Output Voltage VOUT2 Typical Output Ripple VOUT2 Output Regulation VOUT2 Nominal Switching Frequencies Burst Mode Operation Phase INTVCC V2P5 the bottom-side of the IC for better thermal performance. These features, plus a programmable operating frequency range from 500kHz to 4MHz (2MHz switching frequency with the RT pin connected to INTVCC), make the DC1895 demo board an ideal circuit for use industrial or distributed power applications. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Burst Mode, Linear Technology 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 CONDITIONS RUN Pin = GND RUN Pin = VIN VIN = 3.6V to 20V, IOUT1 = 0A to 3A VIN = 12V, IOUT1 = 3A (20MHz BW) Line Load VIN = 3.6V to 20V, IOUT2 = 0A to 3A VIN = 12V, IOUT2 = 3A (20MHz BW) Line Load RT Pin connected to 324k RT Pin = INTVCC Channel 1: VIN = 12V, VOUT1 = 1.8V, fSW = 1 MHz Channel 2: VIN = 12V, VOUT2 = 3.3V, fSW = 1 MHz Channel 1: VIN = 12V, VOUT1 = 1.8V, fSW = 2 MHz Channel 2: VIN = 12V, VOUT2 = 3.3V, fSW = 2 MHz Phase Pin = INTVCC Phase Pin = GND VALUE 3.6V 20V Shutdown Operating 1.2V ±4% (1.152V to 1.248V) 1.5V ±4% (1.44V to 1.56V) 1.8V ±4% (1.728V to 1.872V) < 30mVP-P ±1% ±1% 2.5V ±4% (2.4V to 2.6V) 3.3V ±4% (3.168V to 3.432V) 5V ±4% (4.8V to 5.2V) < 30mVP-P ±1% ±1% 1MHz 2MHz IOUT1 = 1.3A IOUT2 = 850mA IOUT1 = 800mA IOUT2 = 500mA Out-of-Phase In Phase 3.3V 2.5V dc1895afa 1 DEMO MANUAL DC1895A Quick Start Procedure The DC1895 is easy to set up to evaluate the performance of the LTC3633A. For a proper measurement equipment configuration, set up the circuit according to the diagram in Figure 1. 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 the proper scope probe technique in Figure 2. Please follow the procedure outlined below for proper operation. 1.Connect the input power supply to the VIN and GND terminals. Connect the loads between the VOUT and GND terminals. Refer to Figure 1 for the proper measurement equipment setup. Before proceeding to operation, insert jumper shunts XJP1 and XJP2 into the OFF positions of headers JP1 and JP2, shunt XJP11 into the ON position (180° outof-phase) of PHASE header JP11, shunts XJP3 and XJP4 into the soft-start (ss) positions of headers JP3 and JP4, shunt XJP8 into the forced continuous mode (FCM) position of MODE header JP8, shunt XJP14 into the 1MHz position of the frequency (FREQ) header JP14, shunts XJP12 and XJP13 into the external (EXT) compensation positions of headers JP12 and JP13, and shunt XJP6 into the VOUT1 voltage options of choice of header JP6: 1.2V, 1.5V, or 1.8V, and a shunt into the VOUT2 voltage option of choice: 2.5V (header JP15), 3.3V (header JP5), or 5V (header JP7). 2.Apply 5.5V at VIN. Measure both VOUTs; they should read 0V. If desired, one can measure the shutdown supply current at this point. The supply current will be less than 100µA in shutdown. 2 3.Turn on VOUT1 and VOUT2 by shifting shunts XJP1 and XJP2 from the OFF positions to the ON positions. Both output voltages should be within a tolerance of ±2%. 4.Vary the input voltage from 5.8V (the minimum VIN is dependent on VOUT) to 20V, and the load currents from 0A to 3A. Both output voltages should be within ±4% tolerance. 5.Set the load current of both outputs to 3A and the input voltage to 20V, and then measure each output ripple voltage (refer to Figure 2 for proper measurement technique); they should each measure less than 30mVAC. Also, observe the voltage waveforms at the switch nodes (Pins 23 and 24 for reg.1 and 13 and 14 for reg.2) of each regulator. The switching frequencies should be between 800kHz and 1.2MHz (t = 1.25µs and 0.833µs). To realize 2MHz operation, change the shunt position on header JP14. In all cases, both switch node waveforms should be rectangular in shape, and 180°out-of-phase with each other. Change the shunt position on header JP11 to set the switch waveforms in phase with respect to each other. To operate the ckt.s in Burst Mode Operation, change the shunt in header JP8 to the Burst Mode position. When finished, insert shunts XJP1 and XJP2 to the OFF position(s) and disconnect the power. Warning: If the power for the demo board is carried in long leads, the input voltage at the part could “ring”, which could affect the operation of the circuit or even exceed the maximum voltage rating of the IC. To eliminate the ringing, a small tantalum capacitor (for instance, AVX part number TPSY226M035R0200) is inserted on the pads between the input power and return terminals on the bottom of the demo board. The (greater) ESR of the tantalum will dampen the (possible) ringing voltage due to the use of long input leads. On a normal, typical PCB, with short traces, this capacitor is not needed. dc1895afa DEMO MANUAL DC1895A Quick Start Procedure – – + + LOAD – – + – + – + + VO1 VS1 – + + + – – + + – VS2 – + LOAD – VO2 dc1895af F01 Figure 1. Proper Measurement Equipment Setup GND VIN Figure 2. Measuring Input or Output Ripple dc1895afa 3 DEMO MANUAL DC1895A Quick Start Procedure VIN = 12V, VOUT1 = 1.8V at IOUT1 = 3A, VOUT2 = 3.3V at IOUT2 = 3A FORCED CONTINUOUS MODE fSW = 1MHz EXTERNAL COMPENSATION: RITHX = 13k, CITHX = 220pF TRACE 1: VOUT1 (10V/DIV) TRACE 3: VOUT1 AC VOLTAGE (20mV/DIV AC) TRACE 2: VOUT2 (10V/DIV) TRACE 4: VOUT2 AC VOLTAGE (20mV/DIV AC) Figure 3. LTC3633A Switch Operation 4 dc1895afa DEMO MANUAL DC1895A Quick Start Procedure VIN = 12V, VOUT1 = 1.8V, 3A LOAD STEP (0A < to > 3A) FORCED CONTINUOUS MODE fSW = 2MHz EXTERNAL COMPENSATION: RITH = 13k, CITH = 220pF TRACE 3: OUTPUT VOLTAGE (100mV/DIV AC) TRACE 4: OUTPUT CURRENT (1A/DIV) Figure 4. VOUT1 Load Step Response dc1895afa 5 DEMO MANUAL DC1895A Quick Start Procedure VIN = 12V, VOUT2 = 3.3V, 3A LOAD STEP (0A < to > 3A) FORCED CONTINUOUS MODE fSW = 2MHz EXTERNAL COMPENSATION: RITH = 13k, CITH = 220pF TRACE 3: OUTPUT VOLTAGE (100mV/DIV AC) TRACE 4: OUTPUT CURRENT (1A/DIV) Figure 5. VOUT2 Load Step Response 6 dc1895afa DEMO MANUAL DC1895A Quick Start Procedure 100 90 VO2 = 3.3V, fSW = 1 MHz VO2 = 3.3V, fSW = 2 MHz VO1 = 1.8V, fSW = 1 MHz VO1 = 1.8V, fSW = 2 MHz 80 70 EFFICIENCY (%) 60 50 40 30 20 VIN = 12V Burst Mode OPERATION L1 = 1 µH L2 = 2.2 µH 2020BZ VISHAY 10 0 1.00E-03 1.00E-02 1.00E-01 LOAD CURRENT (A) 1.00E+00 1.00E+01 dc1895af F06 Figure 6. LTC3633A DC1895 Efficiency dc1895afa 7 DEMO MANUAL DC1895A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C1, C2 CAP, 0603, 0.1µF, 10%, 50V, X7R TDK C1608X7R1H104K 2 2 CFFW1, CFFW2 CAP, 0402, 10pF, 5%, 25V, NPO AVX 04023A100JAT2A 3 4 CIN1 to CIN4 CAP, 1210, 22µF, 20%, 25V, X7R TAIYO YUDEN TMK325B7226MM-TR 4 4 COUT1 to COUT4 CAP, 1206, 22µF, 20%, 6.3V, X5R TAIYO YUDEN JMK316BJ226ML-T 5 1 CVCC CAP, 0603, 1µF, 10%, 16V, X5R AVX 0603YD105KAT2A 6 1 L1 IND, 1.0µH VISHAY IHLP-2020BZER1R0M01 7 1 L2 IND, 2.2µH VISHAY IHLP-2020BZER2R2M01 8 2 R3, R5 RES, 0402, 29.4kΩ, 1%, 1/16W VISHAY CRCW040229K4FKED 9 1 R4 RES, 0402, 84.5kΩ, 1%, 1/16W VISHAY CRCW040284K5FKED 10 1 R8 RES, 0402, 11.5kΩ, 1%, 1/16W VISHAY CRCW040211K5FKED 11 1 U1 IC, DUAL STEP-DOWN REGULATOR LINEAR TECH, LTC3633AEUFD Additional Demo Board Circuit Components 1 0 CC1, CC2 CAP, 0402, 10pF, 5%, 25V, NPO OPTION AVX 04023A100JAT2A OPTION 2 2 CIN5, CIN6 CAP, 603,2 3.3µF, 20%, 35V TANT AVX TAJW335M035R 3 2 CITH1, CITH2 CAP, 0402, 220pF, 10%, 25V C0G AVX 04023A221KAT2A 4 0 CLDO CAP, 0603, 1µF, 10%, 16V, X5R OPTION AVX 0603YD105KAT2A OPTION 5 2 COUT5, COUT6 CAP, 0805, 10µF, 20%, 6.3V, X5R TDK C2012X5R0J106M 6 2 CTR1, CTR2 CAP, 0402, 4700pF, 10%, 50V, X7R AVX 04025C472KAT 7 2 CVCC1, C2P5 CAP, 0603, 1µF, 10%, 16V, X5R AVX 0603YD105KAT2A 8 2 C2P5, CVCC1 CAP, 0603, 1µF, 10%, 16V, X5R AVX 0603YD105KAT2A 9 2 RITH1, RITH2 RES, 0402, 13kΩ, 1%, 1/16W NIC NRC04F1302TRF 10 2 RPG1, RPG2 RES, 0402, 100kΩ, 5%, 1/16W VISHAY CRCW0402100KJNED 11 3 R1, R2, RPHMDE RES, 0402, 1MΩ, 5%, 1/16W VISHAY CRCW04021M00JNED 12 1 RT RES, 0402, 324kΩ, 1%, 1/16W VISHAY CRCW0402324KFKED 13 2 RTR1, RTR2 RES, 0402, 0Ω, JUMPER VISHAY CRCW04020000Z0ED 14 0 RTR3, RTR4 RES, 0402, OPTION OPTION 15 1 R6 RES, 0402, 18.7kΩ, 1%, 1/16W VISHAY CRCW040218K7FKED 16 1 R7 RES, 0402, 19.6kΩ, 1%, 1/16W VISHAY CRCW040219K6FKED 17 1 R9 RES, 0402, 14.7kΩ, 1%, 1/16W VISHAY CRCW040214K7FKED 18 1 R10 RES, 0402, 26.7kΩ, 1%, 1/16W VISHAY CRCW040226K7FKED 19 1 R11 RES, 0402, 10kΩ, 5%, 1/16W VISHAY CRCW040210K0JNED TURRET MILL-MAX 2501-2-00-80-00-00-07-0 Hardware: For Demo Board Only 1 16 E1 to E16 2 8 JP1 to JP4, JP11 toJP14 HEADER, 3Pin, 2mm SULLINS, NRPN031PAEN-RC 3 3 JP5, JP7, JP15 HEADER, 2Pin, 2mm SULLINS, NRPN021PAEN-RC 4 2 JP6, JP8 HEADER, 3Pin, DBL ROW 2mm SULLINS, NRPN032PAEN-RC 5 11 JP1 to JP4, JP6 to JP8, JP11 to JP14 SHUNT, 2mm SAMTEC 2SN-BK-G 8 dc1895afa 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 E16 E2 E15 E6 E4 E1 [1] CIN5 3.3uF 35V 6032 [1] + CIN6 3.3uF 35V 6032 + 3 5 4 6 CIN4 22uF 25V 1210 CIN3 22uF 25V 1210 VIN VIN JP6 1 2 VO1 SELECT 1.8V 1.5V CIN2 22uF 25V 1210 R3 29.4K 1% 1M RPHMDE INT EXT 3 2 1 2MHz (INT.) 1MHz JP12 ITH1 L1 1.0uH 3 2 1 VIN C1 0.1uF R1 1M JP3 3 2 1 23 24 20 5 2. ALL RESISTOR AND CAPACITOR CASE SIZE ARE 0402. 4 11 9 12 14 13 17 18 6 JP4 SS VIN 3 2 1 TRACK CC2 10pF OPT INTVCC 220pF CITH2 RITH2 13K 1% C2 L2 2.2uH 0.1uF R2 1M 3 2 1 TRACK/SS2 JP14 3 6 JP13 ITH2 5 3 1 RTR4 OPT R8 11.5K 1% R6 18.7K 1% R10 26.7K 1% COUT2 22uF 6.3V 1206 C2P5 1uF 5V 3.3V 2.5V 2 N/A JP7 JP5 GND GND VOUT2 V2P5 GND TECHNOLOGY SYNC APPROVED TOM G. 1 1 LTC3633AEUFD DEMO CIRCUIT 1895A 10/16/12 14:29:17 1 1 R11 10k E12 DATE 08/23/12 PGOOD2 TRACK2 VO2 SELECT E14 E7 E5 E13 E3 E8 E11 1 DUAL SYNCHRONOUS STEP-DOWN REGULATOR CLDO 1uF OPT COUT6 10uF 6.3V 0805 JP15 COUT4 22uF 6.3V 1206 VOUT2 0 RTR2 PROTO 1 REVISION HISTORY DESCRIPTION REV FCM (FORCED CONTINUOUS MODE) ECO BURST MODE SYNC INTVCC INT JP8 MODE 3 2 1 2 R4 84.5K 1% EXT OFF ON CFFW2 10pF JP2 RUN2 4 ITH2 VFB2 VON2 SW2 SW2 BOOST2 V2P5 RUN2 RPG2 100K CTR2 4700pF 3 RT 324K 1% 220pF CITH1 ITH1 VFB1 VON1 VIN LTC3633AEUFD U1 1uF 1uF CVCC 2 INTVCC INTVCC RITH1 13K 1% 26 28 25 SW1 SW1 BOOST1 PHMODE RUN1 VIN CTR1 4700pF 3 CVCC1 INTVCC E10 2 1 FREQ CC1 10pF OPT 2 3 RPG1 100K JP1 CFFW1 10pF OFF ON RUN1 TRACK SS TRACK/SS1 [1] CIN5 AND CIN6 ARE INSERTED ON DC1895A TO DAMPEN THE (POSSIBLE) RINGING VOLTAGE DUE TO THE USE OF LONG INPUT LEADS. ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES, CIN5 AND CIN6 ARE NOT NEEDED. R9 14.7K 1% R7 19.6K 1% R5 29.4K 1% COUT1 22uF 6.3V 1206 INTVCC 1.2V 3 2 1 CIN1 22uF 25V 1210 COUT3 22uF 6.3V 1206 VOUT1 JP11 PHASE OFF ON RTR3 OPT COUT5 10uF 6.3V 0805 0 RTR1 NOTES: UNLESS OTHERWISE SPECIFIED, VIN2 VIN1 GND GND 3A VOUT1 PGOOD1 TRACK1 E9 4 1 PGOOD1 21 22 PVIN1 PVIN1 RT 5 INTVCC INTVcc 27 TRACK/SS1 10 TRACK/SS2 19 SGND 7 PGND 29 8 PGOOD2 15 16 PVIN2 PVIN2 MODE/SYNC 4 5 A B C D DEMO MANUAL DC1895A Schematic Diagram dc1895afa 9 DEMO MANUAL DC1895A 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 10 Linear Technology Corporation dc1895afa LT 0514 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2012