Evaluation Board for the ADP220/ADP221 EVAL-ADP220/ADP221 FEATURES GENERAL DESCRIPTION Input voltage range: 2.5 V to 5.5 V Output current range: 0 mA to 200 mA per output Output voltage accuracy: ±1% Operating temperature range: −40°C to +125°C The ADP220/ADP221 evaluation boards are used to demonstrate the functionality of the ADP220/ADP221 series of linear regulators. Simple device measurements such as line and load regulation, dropout, and ground current can be demonstrated with just a single voltage supply, a voltmeter, a current meter, and load resistors. For more details about the ADP220/ADP221 linear regulator, see the ADP220/ADP221 data sheet. 07575-001 EVALUATION BOARD DIGITAL PICTURE Figure 1. ADP220/ADP221 Evaluation Board Rev. 0 Evaluation boards are only intended for device evaluation and not for production purposes. Evaluation boards are supplied “as is” and without warranties of any kind, express, implied, or statutory including, but not limited to, any implied warranty of merchantability or fitness for a particular purpose. No license is granted by implication or otherwise under any patents or other intellectual property by application or use of evaluation boards. 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. Analog Devices reserves the right to change devices or specifications at any time without notice. Trademarks and registered trademarks are the property of their respective owners. Evaluation boards are not authorized to be used in life support devices or systems. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 Fax: 781.461.3113 ©2008 Analog Devices, Inc. All rights reserved. EVAL-ADP220/ADP221 TABLE OF CONTENTS Features .............................................................................................. 1 Dropout Voltage ............................................................................5 General Description ......................................................................... 1 Ground Current Measurements ......................................................6 Evaluation Board Digital Picture .................................................... 1 Ground Current Consumption ...................................................6 Revision History ............................................................................... 2 Printed Circuit Board Layout Considerations ...............................7 Evaluation Board Hardware and Schematic ................................. 3 Ordering Information .......................................................................8 Evaluation Board Configurations .............................................. 3 Bill of Materials ..............................................................................8 Output Voltage Measurements ....................................................... 4 Ordering Guide .............................................................................8 Line Regulation ............................................................................. 5 ESD Caution...................................................................................8 Load Regulation............................................................................ 5 REVISION HISTORY 10/08—Revision 0: Initial Version Rev. 0 | Page 2 of 8 EVAL-ADP220/ADP221 EVALUATION BOARD HARDWARE AND SCHEMATIC EVALUATION BOARD CONFIGURATIONS 2 1 The ADP220/ADP221 evaluation boards are supplied with different components, depending on which version is ordered. Components common to all versions are C1, C2, C3, J1, and J2. Figure 2 shows the schematic of this evaluation board configuration. J1 TB2 TB5 A VOUT1 = 2.8V VOUT1 EN1 C2 TB7 U1 TB4 B GND TB1 VIN = 3.3V TO 4.2V VIN C1 TB3 C EN2 TB6 VOUT2 VOUT2 = 2.8V C3 Figure 2. Evaluation Board Schematic Table 1. Evaluation Board Hardware Components Component U1 1 C1 C2, C3 J1, J2 1 Function Linear regulator Input capacitor Output capacitors Jumper Description ADP220/ADP221 low dropout linear regulator. 1 μF input bypass capacitor, 0402 case. 2.2 μF output capacitors; 0402 case. Required for stability and transient performance. These jumpers connect EN1 and EN2 to VIN for automatic startup. Component varies depending on the evaluation board type ordered. Rev. 0 | Page 3 of 8 07575-002 J2 TOP VIEW (Not to scale) EVAL-ADP220/ADP221 OUTPUT VOLTAGE MEASUREMENTS VOLTMETER LOAD 1.99711 + – VOLTAGE SOURCE + – VOLTMETER 1.99711 + – 07575-003 LOAD Figure 3. Output Voltage Measurement Setup Figure 3 shows the evaluation board can be connected to a voltage source and voltmeters for basic output voltage accuracy measurements. A resistor can be used as the load for the regulator. Ensure that the resistor has a power rating adequate to handle the power expected to be dissipated across it. An electronic load can also be used as an alternative. In addition, ensure that the voltage source can supply enough current for the expected load levels. Follow these steps to connect to a voltage source and voltmeters: 1. 2. 3. 4. 5. Connect the negative terminal (−) of the voltage source to one of the GND pads on the evaluation board. Connect the positive terminal (+) of the voltage source to the VIN pad of the evaluation board. Connect a load between VOUT1 or VOUT2 and one of the GND pads. Connect the negative terminal (−) of the voltmeter to one of the GND pads. Connect the positive terminals (+) of the voltmeters TB5 (VOUT1) or TB6 (VOUT2). The voltage source can now be turned on. If J1 or J2 is inserted (connecting EN1 or EN2 to VIN for automatic startup), the regulator powers up. Rev. 0 | Page 4 of 8 EVAL-ADP220/ADP221 2.85 LINE REGULATION For line regulation measurements, the regulator’s outputs are monitored while its input is varied. For good line regulation, the outputs must change as little as possible with varying input levels. To ensure that the device is not in dropout mode during this measurement, VIN must be varied between VOUTNOM + 0.5 V (or 2.5 V, whichever is greater) and VINMAX. For example, for an ADP220/ADP221 with fixed 2.8 V output, VIN needs to be varied between 3.3 V and 5.5 V. This measurement can be repeated under different load conditions. Figure 4 shows the typical line regulation performance of an ADP220/ADP221 with fixed 2.8 V output. VOUT = 2.8V VIN = 3.3V TA = 25°C OUTPUT VOLTAGE (V) 2.83 2.81 2.79 2.75 0.01 0.1 100 1k DROPOUT VOLTAGE Dropout voltage can be measured using the configuration shown in Figure 3. Dropout voltage is defined as the input-tooutput voltage differential when the input voltage is set to the nominal output voltage. This applies only for output voltages above 2.5 V. Dropout voltage increases with larger loads. For more accurate measurements, a second voltmeter can be used to monitor the input voltage across the input capacitor. The input supply voltage may need to be adjusted to account for IR drops, especially if large load currents are used. Figure 6 shows the typical curve of the dropout voltage measurement with different load currents. 2.81 2.79 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 INPUT VOLTAGE (V) 5.3 5.5 07575-006 2.77 Figure 4. Output Voltage vs. Input Voltage 250 LOAD REGULATION 2.5V 2.8V 3.3V 200 DROPOUT VOLTAGE (mV) For load regulation measurements, the regulator’s outputs are monitored while the loads are varied. For good load regulation, the outputs must change as little as possible with varying loads. The input voltage must be held constant during this measurement. The load currents can be varied from 0 mA to 200 mA per output. Figure 5 shows the typical load regulation performance of a single 2.8 V output of the ADP220/ADP221 for an input voltage of 3.3 V. 150 100 50 0 1 10 100 LOAD CURRENT (mA) Figure 6. Dropout Voltage vs. Load Current, VOUT = 2.8 V Rev. 0 | Page 5 of 8 1k 07575-014 2.83 OUTPUT VOLTAGE (V) 10 Figure 5. Output Voltage vs. Load Current LOAD = 10µA LOAD = 100µA LOAD = 1mA LOAD = 10mA LOAD = 100mA LOAD = 200mA VOUT = 2.8V TA = 25°C 2.75 3.3 1 LOAD CURRENT (mA) 2.85 07575-005 2.77 EVAL-ADP220/ADP221 GROUND CURRENT MEASUREMENTS LOAD VOLTAGE SOURCE AMMETER 0.00049 + – + – 07575-007 LOAD Figure 7. Ground Current Measurement Use the following steps to connect to a voltage source and ammeter: 2. 3. 4. Connect the positive terminal (+) of the voltage source to the VIN pad on the evaluation board. Connect the positive terminal (+) of the ammeter to one of the GND pads of the evaluation board. Connect the negative terminal (−) of the ammeter to the negative (−) terminal of the voltage source. Connect a load between VOUT1 and/or VOUT2 of the evaluation board and the negative (−) terminal of the voltage source. Ground current measurements can determine how much current the regulator’s internal circuits are consuming while the circuits perform the regulation function. To be efficient, the regulator needs to consume as little current as possible. Typically, the regulator uses the maximum current when supplying its largest load level (200 mA per output). Figure 8 shows the typical ground current consumption for various load levels at an input voltage of 3.3 V for a single output. When the device is disabled (EN1 and EN2 = GND), ground current drops to less than 1 μA. The voltage source can now be turned on. If J1 or J2 is inserted (connecting EN1 or EN2 to VIN for automatic startup), the regulator powers up. 140 120 VOUT = 2.8V VIN = 3.3V 100 BOTH OUTPUTS 80 SINGLE OUTPUT 60 40 20 0 0.01 0.1 1 10 LOAD CURRENT (mA) 100 Figure 8. Ground Current vs. Load Current Rev. 0 | Page 6 of 8 1k 07575-008 1. GROUND CURRENT CONSUMPTION GROUND CURRENT (uA) Figure 7 shows how the evaluation board can be connected to a voltage source and an ammeter for ground current measurements. A resistor can be used as the load for the regulator. Ensure that the resistor has a power rating adequate to handle the power expected to be dissipated across it. An electronic load can be used as an alternative. Ensure that the voltage source used can supply enough current for the expected load levels. EVAL-ADP220/ADP221 PRINTED CIRCUIT BOARD LAYOUT CONSIDERATIONS Heat dissipation from the package can be improved by increasing the amount of copper attached to the pins of the ADP220/ADP221. Here are a few general tips when designing PCBs: • 07575-010 • Place the input capacitor as close as possible to the VIN and GND pins. Place the output capacitors as close as possible to the VOUT1, VOUT2, and GND pins. Use 0402 or 0603 size capacitors and resistors to achieve the smallest possible footprint solution on boards where area is limited. Figure 10. Typical Board Layout, Bottom Side 07575-009 • Figure 9. Typical Board Layout, Top Side Rev. 0 | Page 7 of 8 EVAL-ADP220/ADP221 ORDERING INFORMATION BILL OF MATERIALS Table 2. Qty 1 2 2 1 Reference Designator C1 C2, 3 J1, J2 U1 Description Capacitor, MLCC, 1.0 μF, 10 V, 0402, X5R Capacitor, MLCC, 2.2 μF, 4 V, 0402, X5R Header, single, STR, 2 pins IC, LDO regulator Manufacturer/Vendor Murata or equivalent Murata or equivalent Digi-Key Corp. Analog Devices, Inc. Vendor Part No. GRM155R61A105KE15 GRM155R60G225ME15 S1012E-36-ND ADP220ACBZ-2828R7 ADP221ACBZ-2828R7 ORDERING GUIDE Model ADP220-2828-EVALZ 1 ADP221-2828-EVALZ1 1 Output Voltage (V) 2.8/2.8 2.8/2.8 Description 2.8 V/2.8 V evaluation board 2.8 V/2.8 V with output discharge evaluation board Z = RoHS Compliant Part. ESD CAUTION ©2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. EB07575-0-10/08(0) Rev. 0 | Page 8 of 8