EVAL-ADP2311 User Guide UG-653 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 ADP2311, Dual, 1 A, 18 V Synchronous Step-Down Regulator with Fail-Safe Voltage Monitoring FEATURES GENERAL DESCRIPTION Input voltage: 4.5 V to 18 V ±1.0% output accuracy Integrated MOSFET: 110 mΩ/60 mΩ typical Continuous output current: 1 A/1 A Power fail comparator generates warning Power-on reset with programmable delay timer Adjustable voltage monitor for power-down Watchdog refresh input Dual phase with 180° out of phase operation Fixed switching frequency: 300 kHz Internal compensation and soft start Stable with low effective series resistance (ESR) output ceramic capacitors Precision enable input Power feedback during power off Undervoltage lockout (UVLO), overcurrent protection (OCP), overvoltage protection (OVP), and thermal shutdown (TSD) The ADP2311 evaluation board is a complete, dual, 1 A step-down regulator solution that allows users to evaluate the performance of the ADP2311 with a near ideal printed circuit board (PCB) layout. The outputs of the ADP2311 evaluation board are preset to 1.2 V and 3.3 V for Channel 1 and Channel 2, respectively. The VIN threshold of the power fail input is set at 8.99 V. Different output and power fail input voltages can be achieved by changing the appropriate passive components. Full details on the ADP2311 dual regulator are provided in the ADP2311 data sheet, available from Analog Devices, Inc., which should be consulted in conjunction with this user guide. 11995-001 ADP2311 EVALUATION BOARD Figure 1. PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | Page 1 of 8 UG-653 EVAL-ADP2311 User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Evaluation Board Schematic and Artwork.....................................5 General Description ......................................................................... 1 ADP2311 Evaluation Board Schematic ......................................5 ADP2311 Evaluation Board ............................................................ 1 PCB Layout ....................................................................................6 Revision History ............................................................................... 2 Ordering Information .......................................................................8 Using the Evaluation Board............................................................. 3 Bill of Materials ..............................................................................8 Powering Up the Evaluation Board ............................................ 3 Measuring Evaluation Board Performance .................................. 3 Modifying the Evaluation Board ................................................ 4 REVISION HISTORY 3/14—Revision 0: Initial Version Rev. 0 | Page 2 of 8 EVAL-ADP2311 User Guide UG-653 USING THE EVALUATION BOARD POWERING UP THE EVALUATION BOARD Turning On the Evaluation Board The ADP2311 evaluation board is supplied fully assembled and tested. Before applying power to the evaluation board, follow the procedures in this section. When the power source and load are connected to the evaluation board, it can be powered for operation. Jumper J20 Setting (Enable) 1. 2. 3. Jumper J20 is used to control the ADP2311. Use one of the following methods to enable or to disable the device: • • To enable the ADP2311, short the middle pin of J20 (EN) to high. To disable the ADP2311, short the middle pin of J20 (EN) to low. 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 J4 (VIN) of the evaluation board, and connect the negative terminal of the power source to J6 (GND) of the evaluation board. 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 J6 (GND), and the negative lead (−) of the ammeter to J4 (VIN). Output Load To turn on the evaluation board, perform the following steps: Ensure that the power source voltage is >4.5 V and <18 V. Ensure that EN is high and monitor the output voltage. Turn on the load, check that it is drawing the proper load current, and verify that the output voltage maintains its regulation. MEASURING EVALUATION BOARD PERFORMANCE Measuring the Switching Waveform To observe the switching waveform with an oscilloscope, place the oscilloscope probe tip at Test Point J2 (SW1) and J10 (SW2) with the probe ground at GND. Set the scope to dc with the appropriate voltage and time divisions. The switching waveform must alternate approximately between 0 V and the input voltage. Measuring Load Regulation Load regulation can be tested by observing the change in the output voltage with increasing output load current. Measuring Line Regulation Vary the input voltage and examine the change in the output voltage with a fixed output current. Line Transient Response Before connecting the load, ensure that the board is turned off. Connect an electronic load or resistor to set the load current. To connect a load to the output of Channel 1, connect the positive terminal of the load to J5 (VOUT1) of the evaluation board and connect the negative terminal of the load to J7 (GND). To connect a load to the output of Channel 2, connect the positive terminal of the load to J12 (VOUT2) of the evaluation board and connect the negative terminal of the load to J13 (GND). Input and Output Voltmeter Measure the input and output voltages using voltmeters. Make sure 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 J1 (VIN_S) and the negative terminal to J9 (GND_S). Likewise, to measure the output voltage, connect the positive terminal of the voltmeter to J3 (VOUT1_S) or J11 (VOUT2_S) and the negative terminal to J8 (GND1_S) or J14 (GND2_S). Generate a step input voltage change and observe the behavior of the output voltage using an oscilloscope. 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= VOUT × I OUT V IN × I IN 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 by connecting a current loop in series. A current probe can be connected onto this wire. Rev. 0 | Page 3 of 8 UG-653 EVAL-ADP2311 User Guide 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. 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. To limit the output voltage accuracy degradation due to the FBx bias current (0.1 µA maximum) to less than 0.5% (maximum), ensure that the bottom divider string resistors, R2 and R8, is less than 30 kΩ. The top resistors, R1 and R5, value is calculated using the following equations: For Channel 1, V − 0.6 V R1 = R2 × OUT1 0.6 V For Channel 2, V − 0.6 V R5 = R8 × OUT2 0.6 V When the output voltage of Channel 1 is changed, the values of the inductor (L1) and the output capacitors (C4 and C5) must be recalculated and changed to ensure stable operation (see the ADP2311 data sheet for details on external component selection). Likewise, if the output voltage of Channel 2 is changed, the values of the inductor (L2) and the output capacitors (C8 and C9) must be recalculated and changed. 11995-002 Changing the VIN Threshold of Power Fail (PFI) Figure 2. Measuring Output Voltage Ripple The evaluation board sets the VPFI_RISING at 8.99 V and the VPFI_FALLING at 8.61 V. It can be changed with different R4 and R7 value. Using the following equation to calculate the R4 and R7: MODIFYING THE EVALUATION BOARD To modify the ADP2311evaluation board configuration, unsolder and/or replace/remove the appropriate passive components or jumpers on the board. VPFI _ RISING = 0.6 V × R 4 + R7 R7 VPFI _ FALLING = 0.575 V × Changing the Output Voltages R 4 + R7 R7 Changing the VIN Threshold of Voltage Monitoring (VM2) The output voltage setpoints of the ADP2311 can be changed by replacing the R1, R2, R5, and R8 resistors with the resistor values shown in Table 1. The evaluation board sets the VVM2_RISING at 5.41 V and the VVM2_FALLNG at 5 V. It can be changed with different R3 and R6 value. Table 1. Resistive Divider for Various Output Voltages Using the following equation to calculate R3 and R6: VOUT (V) 1.0 1.2 1.5 1.8 2.5 3.3 5.0 R1/R5, ±1% (kΩ) 10 10 15 20 47.5 10 22 R2/R8, ±1% (kΩ) 15 10 10 10 15 2.21 3 Rev. 0 | Page 4 of 8 VVM 2 _ RISING = 0.65 V × R3 + R6 R6 VVM 2 _ FALLING = 0.6 V × R3 + R6 R6 EVAL-ADP2311 User Guide UG-653 EVALUATION BOARD SCHEMATIC AND ARTWORK ADP2311 EVALUATION BOARD SCHEMATIC 3 2 1 R13 NC SW2 PGND2 U1 ADP2311 FB1 10 1 10uF/25V/1206 C6 R3 499k 1 4 23 PFI SW4 VM2 C10 1uF PFO POR 6 GND nRSTO FB2 1 5 1 PGND3 3 J18 GND R7 35.7k R1 10k 17 C13 NC 24 15 C7 0.1uF R2 10k J10 SW2 12 11 2 L2 22uH C4 C5 2 J5 VOUT1 1 2 J7 GND 1 J8 GND1_S J11 VOUT2_S 1 C8 14 13 R5 10k VREG 8 R6 68.1k 18 7 C14 NC 1 2 J12 VOUT2 1 2 J13 GND 1 J14 GND2_S C9 NC PGND4 2 1 1 1 SW3 VREG J23 GND L1 15uH 47uF/6.3V/1206 J22 VM2 1 BST2 TIMER J21 PFI R4 499k VOUT1_S 2 20 PVIN2 WDI J9 GND_S PGND1 19 47uF/6.3V/1206 2 1 C3 J3 1 47uF/6.3V/1206 NC J6 GND C12 10uF/25V/1206 C2 SW1 PVIN1 J2 SW1 R8 2.21k VREG R9 R10 R11 100k 100k 100k R14 0 1 J15 POR C11 15nF Figure 3. Evaluation Board Schematic for the ADP2311 Rev. 0 | Page 5 of 8 1 J16 PFO 1 J17 nRSTO 1 2 J19 WDI 11995-003 21 C1 0.1uF 1 2 1 BST1 EN 16 pad J4 VIN 22 25 1 10uF/25V/1206 J1 VIN_S 1 R12 NC 9 J20 EN UG-653 EVAL-ADP2311 User Guide 11995-004 PCB LAYOUT 11995-005 Figure 4. ADP2311 Evaluation Board Layer 1, Component Side Figure 5. ADP2311 Evaluation Board Layer 2, Ground Plane Rev. 0 | Page 6 of 8 UG-653 11995-006 EVAL-ADP2311 User Guide 11995-007 Figure 6. ADP2311 Evaluation Board Layer 3, Power Plane Figure 7. ADP2311 Evaluation Board Layer 4, Bottom Side Rev. 0 | Page 7 of 8 UG-653 EVAL-ADP2311 User Guide ORDERING INFORMATION BILL OF MATERIALS Table 2. Qty 2 1 3 3 1 1 1 2 1 1 3 2 1 1 1 3 2 1 1 Reference Designator C1, C7 C2 C3, C6, C12 C4, C5, C8 C10 C11 C9 C13, C14 L1 L2 R1, R2, R5 R3, R4 R6 R7 R8 R9, R10, R11 R12, R13 R14 U1 15 7 J1, J2, J3, J8, J9, J10, J11, J14 ,J15, J16, J17, J18, J21, J22, J23 J4, J5, J6, J7, J12, J13, J19 1 J20 Description 0.1 µF, 50 V, capacitor, 0603 Optional, capacitor 10 µF, 25 V, capacitor, 1206 47 µF, 6.3 V, capacitor, 1206 1 µF, 16 V, capacitor, 0603 15 nF, 50 V, capacitor, 0603 Optional, capacitor, 1206 Optional, capacitor, 0603 Inductor, L = 15 µH, IRAT = 5.8 A, DCR = 43.75 mΩ Inductor, L = 22 µH, IRAT = 5.6 A, DCR = 60.63 mΩ 10 kΩ,1%, resistor, 0603 499 kΩ,1%,resistor, 0603 68.1 kΩ,1%, resistor, 0603 35.7 kΩ,1%,resistor, 0603 2.21 kΩ,1%, resistor, 0603 100 kΩ,1%, resistor, 0603 Optional, resistor, 0603 0 Ω, resistor, 0603 Dual 1 A, 18 V synchronous, step-down regulator with failsafe voltage monitoring, 24-lead LFCSP_WQ 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 Jumper, 0.1-inch header, 3-way, SIP3 Part Number/Vendor GRM188F51H104ZA01/Murata Optional GRM31CR61E106KA12/Murata GRM31CR60J476ME19L/Murata GRM188F51C105ZA01/Murata GRM188F51H153ZA01/Murata Optional Optional XAL6060-153ME/CoilCraft XAL6060-223ME/CoilCraft CRCW060310K0FKEA/Vishay Dale CRCW0603499KFKEA/Vishay Dale CRCW060368K1FKEA/Vishay Dale CRCW060335K7FKEA/Vishay Dale CRCW06032K21FKEA/Vishay Dale CRCW0603100KFKEA/Vishay Dale Optional CRCW06030000Z0EA/Vishay Dale ADP2311ACPZ-1-R7/Analog Devices M20-9990245/Harwin M20-9990245/Harwin M20-9990346/Harwin 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. ©2014 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. UG11995-0-3/14(0) Rev. 0 | Page 8 of 8