Evaluation Board User Guide UG-504 One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com Evaluation Board for the ADP2380 and ADP2381, 20 V, 4 A/6 A Synchronous Step-Down Regulators with Low-Side Driver FEATURES GENERAL DESCRIPTION Input voltage: 4.5 V to 20 V ±1% output voltage accuracy Integrated 44 mΩ high-side MOSFET Continuous output current 4 A for the ADP2380 6 A for the ADP2381 Programmable switching frequency: 250 kHz to 1.4 MHz Synchronizes to external clock: 250 kHz to 1.4 MHz 180° out-of-phase synchronization Programmable UVLO Power-good output External compensation Internal soft start with external adjustable option Startup into a precharged output The ADP2380/ADP2381 evaluation board is a complete, 4 A/6 A, 20 V, step-down regulator solution that allows users to evaluate the performance of the ADP2380 and the ADP2381 with a nearly ideal printed circuit board (PCB) layout. The switching frequency can be programmed between 250 kHz and 1.4 MHz, or it can be synchronized to an external clock with a 180° phase shift, which provides the possibility for a stackable, multiphase power solution. The output of the ADP2380/ADP2381 evaluation board is preset to 3.3 V, and the switching frequency is set to 500 kHz. Different output voltage settings can be achieved by changing the appropriate passive components. The ambient temperature operating range is −40°C to +85°C. Full details about the ADP2380 and ADP2381 regulators are provided in the ADP2380 and ADP2381 data sheets, which are available from Analog Devices, Inc. The data sheets should be consulted in conjunction with this user guide. 11203-001 DEMO BOARD Figure 1. PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | Page 1 of 12 UG-504 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Evaluation Board Schematics and Artwork ...................................5 General Description ......................................................................... 1 ADP2380 Schematic ......................................................................5 Demo Board ...................................................................................... 1 ADP2381 Schematic ......................................................................6 Revision History ............................................................................... 2 PCB Layout ....................................................................................7 Using the Evaluation Board............................................................. 3 Ordering Information .......................................................................8 Powering Up .................................................................................. 3 Bill of Materials ..............................................................................8 Measuring Evaluation Board Performance .................................. 3 Modifying the Board .................................................................... 4 REVISION HISTORY 12/12—Revision 0: Initial Version Rev. 0 | Page 2 of 12 Evaluation Board User Guide UG-504 USING THE EVALUATION BOARD POWERING UP MEASURING EVALUATION BOARD PERFORMANCE The ADP2380/ADP2381 evaluation board is supplied fully assembled and tested. Before applying power to the evaluation board, follow the procedures in this section. Measuring the Switching Waveform To observe the switching waveform with an oscilloscope, place the oscilloscope probe tip at Test Point J4 (SW) with the probe ground at J16 (GND). Set the scope to dc with the appropriate voltage and time divisions. The switching waveform limits should alternate approximately between 0 V and the input voltage. Jumper J12 (EN/SS) Use one of the following methods to enable or disable the regulator: • • Measuring Load Regulation To enable the regulator, leave Jumper J12 open. To disable the regulator, short Jumper J12. Load regulation can be tested by observing the change in the output voltage with increasing output load current. To minimize the voltage drop, use short, low resistance wires. Input Power Source If the input power source includes a current meter, use that meter to monitor the input current. Connect the positive terminal of the power source to J5 (VIN) of the evaluation board, and the negative terminal of the power source to J14 (GND) of the evaluation board. Measuring Line Regulation If the power source does not include a current meter, connect a current meter in series with the input source voltage. Connect the positive lead (+) of the power source to the positive (+) ammeter terminal, the negative lead (−) of the power source to J14 (GND), and the negative lead (−) of the ammeter to J5 (VIN). Generate a step input voltage change and observe the behavior of the output voltage using an oscilloscope. Output Load Before connecting the load, ensure that the board is turned off. Connect an electronic load or resistor to set the load current. Connect the positive terminal of the load to J6 (VOUT) of the evaluation board and connect the negative terminal of the load to J13 (GND). Vary the input voltage and examine the change in the output voltage with a fixed output current. Line Transient Response Load Transient Response Generate a load current transient at the output and observe the output voltage response using an oscilloscope. Attach the current probe to the wire between the output and the load to capture the current transient waveform. Measuring Efficiency The efficiency, η, is measured by comparing the input power with the output power. η= Input and Output Voltmeter Measure the input and output voltages using voltmeters. Ensure that the voltmeters are connected to the appropriate terminals of the evaluation board and not to the load or power source. If the voltmeters are not connected directly to the evaluation board, the measured voltages are incorrect, due to the voltage drop across the leads and/or connections between the evaluation board, the power source, and/or the load. To measure the input voltage, connect the positive terminal of the voltmeter to J7 (VIN_SENSE) and the negative terminal to J11 (GND_SENSE). Likewise, to measure the output voltage, connect the positive terminal of the voltmeter to J8 (VOUT_SENSE) and the negative terminal to J10 (GND_SENSE). Turning On the Evaluation Board Measure the input and output voltages as close as possible to the input and output capacitors to reduce the effect of voltage drop. Measuring Inductor Current The inductor current can be measured by removing one end of the inductor from its pad and connecting a current loop in series. A current probe can be connected onto this wire. Measuring Output Voltage Ripple To observe the output voltage ripple, place the oscilloscope probe across the output capacitor with the probe ground lead connected to the negative (−) capacitor terminal and the probe tip placed at the positive (+) capacitor terminal. Set the oscilloscope to ac, 10 mV/division, 2 µs/division time base, and 20 MHz bandwidth. When the power source and load are connected to the evaluation board, it can be powered for operation. Perform the following steps to turn on the board: 1. 2. 3. VOUT × I OUT V IN × I IN Ensure that the power source voltage is >4.5 V and <20 V. Ensure that J12 (EN/SS) is open. Turn on the load, ensure that it is drawing the proper load current, and verify that the output voltage maintains its regulation. Rev. 0 | Page 3 of 12 UG-504 Evaluation Board User Guide A standard oscilloscope probe has a long wire ground clip. For high frequency measurements, this ground clip picks up high frequency noise and injects it into the measured output ripple. Figure 2 shows an easy way to measure the output ripple properly. It requires removing the oscilloscope probe sheath and wrapping an unshielded wire around the oscilloscope probe. By keeping the ground length of the oscilloscope probe as short as possible, the true ripple can be measured. Changing the Switching Frequency The switching frequency (fSW) set point can be changed by replacing the R7 resistor with a different value, as shown in the following equation: fSW [kHz] = 57, 600/(R7 [kΩ] + 15) A 215 kΩ resistor sets the frequency to 250 kHz, and a 100 kΩ resistor sets the frequency to 500 kHz. When the switching frequency is changed, the values of the inductor (L1), the output capacitors (C2, C3, C4), and the compensation networks (R8, C10, C11) must be recalculated and changed for stable operation (see the ADP2380 and ADP2381 data sheets for details on external component selection). Changing the Soft Start Time The soft start time of the ADP2380/ADP2381 on the evaluation board is programmed to 4 ms. 11203-002 To change the soft start time, tSS, replace the C9 capacitor value, using the following equation: Figure 2. Measuring Output Voltage Ripple MODIFYING THE BOARD To modify the ADP2380/ADP2381 evaluation board configuration, unsolder and/or replace/remove the appropriate passive components or jumpers on the board. Changing the Output Voltages The output voltage setpoints of the ADP2380 and the ADP2381 can be changed by replacing the R9 and R11 resistors with the resistor values shown in Table 1. Table 1. Resistive Divider for Various Output Voltages VOUT (V) 1.0 1.2 1.5 1.8 2.5 3.3 5.0 R9, ±1% (kΩ) 10 10 15 20 47.5 10 22 C9 [nF] = 5.5 × tSS [ms] Changing the Input Voltage UVLO The default values of PVIN UVLO rising/falling threshold are 4.2 V/3.9 V, and these default values can be replaced by placing an external voltage divider (R4 and R6) to achieve more accurate, externally adjustable UVLO. Lower values of the external resistors are recommended to get high accuracy of the UVLO threshold. Setting R6 to 1 kΩ is a proper choice, and the value of R4 for a chosen input voltage rising threshold is as follows: R4 = (V IN _ RISING 1.2 V) R6 1.2 V where: VIN_RISING is the input voltage rising threshold. The input voltage falling threshold can be determined by the following equation: R11, ±1% (kΩ) 15 10 10 10 15 2.21 3 VIN_FALLING = 1.1 V R4 + 1.1 V R6 External Synchronization To limit output voltage accuracy degradation due to the FB pin bias current (0.1 μA maximum) to less than 0.5% (maximum), ensure that the bottom divider string resistor, R11, is less than 30 kΩ. The value of the top resistor, R9, is calculated using the following equation: To synchronize the regulator to an external clock signal, apply an external clock signal to J9 (SYNC) of the evaluation board. The clock signal must have a logic high level from 1.3 V to 5 V and a logic low level that is below 0.4 V. Set the external clock pulse width to greater than 100 ns and the frequency range to between 250 kHz and 1.4 MHz. During synchronization, the regulator operates in CCM mode, and the rising edge of the switching waveform runs 180° out of phase to the external clock rising edge. R9 = R11 × VOUT 0.6 V 0.6 V When the output voltage is changed, the values of the inductor (L1), the output capacitors (C2, C3, and C4), and the compensation components (R8, C10, and C11) must be recalculated and changed to ensure stable operation (see the ADP2380 and ADP2381 data sheets for details on external component selection). For reliable synchronization, connect a resistor from the RT pin to GND (R7) to program the internal oscillator to run at 90% to 110% of the external synchronization clock signal. Rev. 0 | Page 4 of 12 Rev. 0 | Page 5 of 12 Figure 3. Evaluation Board Schematic for the ADP2380 1 2 1 GND J16 1 C6 C5 R6 NC R4 NC 1 R7 100k 1 SY NC J9 VIN = 12V, VOUT = 3.3V, IOUT = 4A, FSW = 500kHz GND J15 GND J14 GND 1 1 10uF/25V J11 VIN J7 VIN 2 1 R1 100k 1 8 7 6 5 4 3 2 ADP2380 C11 2.2pF C10 1000pF COMP EN/ SS SY NC RT PGOOD UVLO PVIN 2 PVIN 1 BST 16 R2 0 C1 0.1uF R8 73.2k FB GND PGND VREG LD SW1 SW2 R11 2.21k 9 10 11 12 13 14 15 R10 NC R3 R9 10k 0 C12 NC 1 2 J12 C9 22nF U1 J3 PWG 1 J4 SW 1 EXP J5 10uF/25V 1 C8 1uF Q1 FDS6298 4 C7 NC R5 NC 1 4.7uH L1 2 C3 47uF/6.3V C2 100uF/6.3V 17 5 6 7 8 3 2 1 J2 J1 UVLO VREG C4 1 2 1 1 1 2 GND J13 GND J10 VOUT J8 VOUT J6 Evaluation Board User Guide UG-504 EVALUATION BOARD SCHEMATICS AND ARTWORK ADP2380 SCHEMATIC NC 11203-003 Rev. 0 | Page 6 of 12 Figure 4. Evaluation Board Schematic for the ADP2381 1 2 1 GND J16 1 C6 C5 R6 NC R4 NC R7 100k 1 1 VIN = 12V, VOUT = 3.3V, IOUT = 6A, FSW = 500kHz GND J15 GND J14 GND 1 1 10uF/25V J11 VIN J7 VIN 2 1 SY NC J9 R1 100k 1 2 8 7 6 5 4 3 ADP2381 C11 2.2pF C10 680pF COMP EN/ SS SY NC RT PGOOD UVLO PVIN 2 PVIN 1 BST 16 R2 0 C1 0.1uF R8 93.1k FB GND PGND VREG LD SW1 SW2 R11 2.21k 9 10 11 12 13 14 15 R10 NC R3 R9 10k 0 C12 NC 1 2 J12 C9 22nF U1 J3 PWG 1 J4 SW 1 EXP J5 10uF/25V 1 C8 1uF Q1 FDS6298 4 C7 NC R5 NC 1 L1 2.2uH 2 C3 100uF/6.3V C2 100uF/6.3V 17 5 6 7 8 3 2 1 J2 J1 UVLO VREG C4 1 2 1 1 1 2 GND J13 GND J10 VOUT J8 VOUT J6 UG-504 Evaluation Board User Guide ADP2381 SCHEMATIC NC 11203-004 Evaluation Board User Guide UG-504 11203-005 11203-007 PCB LAYOUT Figure 7. Layer 2, Ground Plane Figure 6. Layer 3, Power Plane 11203-008 11203-006 Figure 5. Layer 1, Component Side Figure 8. Layer 4, Bottom Side Rev. 0 | Page 7 of 12 UG-504 Evaluation Board User Guide ORDERING INFORMATION BILL OF MATERIALS Table 2. ADP2380 Bill of Materials Qty 1 1 1 1 2 2 1 1 1 1 1 1 2 2 4 1 1 1 1 Reference Designator C1 C2 C3 C4 C5, C6 C7, C12 C8 C9 C10 C11 L1 Q1 R1, R7 R2, R3 R4, R5, R6, R10 R8 R9 R11 U1 11 J1, J2, J3, J4, J7, J8, J9, J10, J11, J15, J16 J5, J6, J12, J13, J14 5 Description Capacitor, 0.1 µF, 16 V, 0603 Capacitor, 100 µF, 6.3 V, 1210 Capacitor, 47 µF, 6.3 V, 1210 Capacitor, optional, 1210 Capacitor, 10 µF, 25 V, 1206 Capacitor, optional, 0603 Capacitor, 1 µF, 16 V, 0603 Capacitor, 22 nF, 16 V, 0603 Capacitor, 1000 pF, 50 V, 0603 Capacitor, 2.2 pF, 50 V, 0603 Inductor, FDVE1040, L = 4.7 µH, IRAT = 8.2 A, DCR = 12.5 mΩ N-channel MOSFET, VDS = 30 V, RDS(ON) = 9.4 mΩ, ID = 13 A, SO8 Resistor, 100 kΩ, 1%, 0603 Resistor, 0 Ω, 1%, 0603 Resistor, optional, 0603 Resistor, 73.2 kΩ, 1%, 0603 Resistor, 10 kΩ, 1%, 0603 Resistor, 2.21 kΩ, 1%, 0603 Regulator, 20 V, 4 A, synchronous step-down with low-side driver, 16-lead, TSSOP_EP Test point, 2.54 mm pitch SIL vertical PC tail pin header, 6.1 mm mating pin height, tin, SIP1 Connector, 2.54 mm pitch SIL vertical PC tail pin header, 6.1 mm mating pin height, tin, 2-way, SIP2 Rev. 0 | Page 8 of 12 Part Number/Vendor GRM188R71C104KA01D/Murata GRM32ER60J107ME20L /Murata GRM32ER70J476KE19L/Murata Optional/Murata GRM31CR61E106MA12L /Murata Optional/Murata GRM188R61C105KA93D/Murata GRM188R71C223KA01D/Murata GRM188R61H102KA01D/Murata GRM1885C1H2R2BZ01D/Murata FDVE1040-4R7M/Toko FDS6298/Fairchild CRCW0603100KFKEA/Vishay Dale CRCW06030000Z0EA/Vishay Dale Optional/Vishay Dale CRCW060373K2FKEA/Vishay Dale CRCW060310K0FKEA/Vishay Dale CRCW06032K21FKEA/Vishay Dale ADP2380/Analog Devices, Inc. M20-9990245/Harwin M20-9990245/Harwin Evaluation Board User Guide UG-504 Table 3. ADP2381 Bill of Materials Qty 1 2 1 2 2 1 1 1 1 1 1 2 2 4 1 1 1 1 Reference Designator C1 C2, C3 C4 C5, C6 C7, C12 C8 C9 C10 C11 L1 Q1 R1, R7 R2, R3 R4, R5, R6, R10 R8 R9 R11 U1 11 J1, J2, J3, J4, J7, J8, J9, J10, J11, J15, J16 J5, J6, J12, J13, J14 5 Description Capacitor, 0.1 µF, 16 V, 0603 Capacitor, 100 µF, 6.3 V, 1210 Capacitor, optional, 1210 Capacitor, 10 µF, 25 V, 1206 Capacitor, optional, 0603 Capacitor, 1 µF, 16 V, 0603 Capacitor, 22 nF, 16 V, 0603 Capacitor, 680 pF, 50 V, 0603 Capacitor, 2.2 pF, 50 V, 0603 Inductor, FDVE1040, L = 2.2 µH, IRAT = 11.4 A, DCR = 6.1 mΩ N-channel MOSFET, VDS = 30 V, RDS(ON) = 9.4 mΩ, ID = 13 A, SO8 Resistor, 100 kΩ, 1%, 0603 Resistor, 0 Ω, 1%, 0603 Resistor, optional, 0603 Resistor, 93.1 kΩ, 1%, 0603 Resistor, 10 kΩ, 1%, 0603 Resistor, 2.21 kΩ, 1%, 0603 Regulator, 20 V, 6 A, synchronous step-down with low-side driver, 16-lead, TSSOP_EP Test point, 2.54 mm pitch SIL vertical PC tail pin header, 6.1 mm mating pin height, tin, SIP1 Connector, 2.54 mm pitch SIL vertical PC tail pin header, 6.1 mm mating pin height, tin, 2-way, SIP2 Rev. 0 | Page 9 of 12 Part Number/Vendor GRM188R71C104KA01D/Murata GRM32ER60J107ME20L/Murata Optional/Murata GRM31CR61E106MA12L/Murata Optional/Murata GRM188R61C105KA93D/Murata GRM188R71C223KA01D/Murata GRM188R71H681KA01D/Murata GRM1885C1H2R2BZ01D/Murata FDVE1040-2R2M/Toko FDS6298/Fairchild CRCW0603100KFKEA/Vishay Dale CRCW06030000Z0EA/Vishay Dale Optional/Vishay Dale CRCW060393K1FKEA/Vishay Dale CRCW060310K0FKEA/Vishay Dale CRCW06032K21FKEA/Vishay Dale ADP2381/Analog Devices, Inc. M20-9990245/Harwin M20-9990245/Harwin UG-504 Evaluation Board User Guide NOTES Rev. 0 | Page 10 of 12 Evaluation Board User Guide UG-504 NOTES Rev. 0 | Page 11 of 12 UG-504 Evaluation Board User Guide NOTES ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality. Legal Terms and Conditions By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the “Evaluation Board”), you are agreeing to be bound by the terms and conditions set forth below (“Agreement”) unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you (“Customer”) and Analog Devices, Inc. (“ADI”), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal, temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term “Third Party” includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board. Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED “AS IS” AND ADI MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER’S POSSESSION OR USE OF THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI’S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby submits to the personal jurisdiction and venue of such courts. The United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement and is expressly disclaimed. ©2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. UG11203-0-12/12(0) Rev. 0 | Page 12 of 12