Evaluation Board for the ADP1720 EVAL-ADP1720 FEATURES GENERAL DESCRIPTION Input voltage range: 4 V to 28 V Output current range: 0 mA to 50 mA Output voltage accuracy: ±1% Operating temperature range: −40°C to +125°C The ADP1720 evaluation board can be used to demonstrate the functionality of the ADP1720 linear regulator. Depending on what component combinations are used, the evaluation board can be used for ADP1720 fixed output voltage devices and ADP1720 adjustable output voltage devices. Simple device measurements such as line and load regulation, dropout, and ground current can be demonstrated with just a single voltage supply, a voltage meter, a current meter, and load resistors. For more details about the ADP1720 linear regulators, visit www.analog.com. EVALUATION BOARD EVAL-ADP1720 U1 GND C1 GND C2 R1 J1 R2 VIN VOUT GND EN GND/ADJ GND 06768-001 J2 Figure 1. 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. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2007 Analog Devices, Inc. All rights reserved. EVAL-ADP1720 TABLE OF CONTENTS Features .............................................................................................. 1 Load Regulation ............................................................................6 General Description ......................................................................... 1 Dropout Voltage ............................................................................6 Evaluation Board .............................................................................. 1 Ground Current Measurements ......................................................7 Revision History ............................................................................... 2 Ground Current Consumption ...................................................7 Evaluation Board Hardware and Schematic ................................. 3 Ordering Information.......................................................................8 Evaluation Board Configurations................................................... 4 Bill of Materials..............................................................................8 ADP1720 Adjustable Output ...................................................... 4 Ordering Guide .............................................................................8 ADP1720 Fixed Output ............................................................... 4 ESD Caution...................................................................................8 Output Voltage Measurements ....................................................... 5 Line Regulation............................................................................. 5 REVISION HISTORY 6/07—Revision 0: Initial Version Rev. 0 | Page 2 of 8 EVAL-ADP1720 EVALUATION BOARD HARDWARE AND SCHEMATIC GND VIN GND C1 U1 GND/ADJ J1 EN 1 GND/ADJ GND 8 2 IN GND 7 3 OUT GND 6 4 EN GND 5 J2 R1 C2 GND VOUT GND 06768-002 R2 Figure 2. Evaluation Board Schematic Table 1. Evaluation Board Hardware Components Component U1 1 C1 C2 R1, R2 2 J1 J23 1 2 3 Function Linear regulator Input capacitor Output capacitor Output voltage adjust resistors Jumper Jumper Description ADP1720 Low Dropout Linear Regulator. 1 μF Input Bypass Capacitor. 1 μF Output Capacitor. Required for stability and transient performance. External Resistors. Used to set VOUT with the adjustable version of ADP1720. Jumper. Connects EN to VIN for automatic startup. Jumper. Connects the GND/ADJ pin to GND for fixed version devices. Component varies depending on which evaluation board type is ordered. Components present only on boards with ADP1720 adjustable output devices. Components present only on boards with ADP1720 fixed output devices. Rev. 0 | Page 3 of 8 EVAL-ADP1720 EVALUATION BOARD CONFIGURATIONS ADP1720 ADJUSTABLE OUTPUT Evaluation boards that come supplied with ADP1720 adjustable output voltage option devices have the additional R1 and R2 resistors included. Figure 3 shows the schematic of this evaluation board configuration. ADP1720 FIXED OUTPUT Fixed output voltage evaluation boards are available in 3.3 V and 5 V options. For fixed output devices, J2 is inserted to connect the GND/ADJ pin to ground. Figure 4 shows the schematic of this evaluation board configuration. ADP1720 J2 VIN ADP1720 1 GND ADJ 8 R1 2 IN GND 7 3 OUT GND 6 4 EN GND 5 C1 J1 VOUT GND 8 2 IN GND 7 3 OUT GND 6 4 EN GND 5 C2 U1 Figure 4. ADP1720 Fixed Output U1 C2 J1 VOUT 06768-003 VIN GND C1 ADJUSTABLE R2 1 Figure 3. ADP1720 Adjustable Output The output voltage is set based on the following equation: VOUT = 1.225 V (1 + R1/R2) For example, if R1 = 15 kΩ and R2 = 10 kΩ, then VOUT is 3.06 V. Rev. 0 | Page 4 of 8 06768-004 The ADP1720 evaluation boards come supplied with different components depending on which version is ordered. Components common to all versions are C1, C2, and J1. EVAL-ADP1720 OUTPUT VOLTAGE MEASUREMENTS VOLTAGE SOURCE + VOLTAGE METER V EVAL-ADP1720 _ _ U1 GND C1 + GND C2 R1 J1 R2 VIN VOUT LOAD GND GND/ADJ EN 06768-005 J2 GND Figure 5. 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 the VOUT pad and one of the GND pads. Connect the negative terminal (−) of the voltage meter to one of the GND pads, and the positive terminal (+) of the voltage meter to the VOUT pad. The voltage source can now be turned on. If J1 is inserted (this connects EN to VIN for automatic startup), then the regulator powers up. For line regulation measurements, the regulator’s output is monitored while its input is varied. For good line regulation, the output must change as little as possible with varying input levels. To ensure the device is not in dropout during this measurement, VIN must be varied between VOUTNOM + 0.5 V (or 4 V, whichever is greater) to VINMAX. For an ADP1720 with 5 V output, this means VIN needs to be varied between 5.5 V and 28 V. This measurement can be repeated under different load conditions. Figure 6 shows the typical line regulation performance of an ADP1720 with 5 V output. If large load currents are used, then the user must connect the voltage meter as close as possible to the output capacitor to reduce the effects of IR drops. 5.010 ILOAD = 10µA ILOAD = 100µA ILOAD = 1mA ILOAD = 10mA ILOAD = 25mA ILOAD = 50mA 5.008 5.006 5.004 5.002 5.000 4.998 4.996 4.994 06768-006 Follow these steps to connect to a voltage source and voltage meter: LINE REGULATION VOUT (V) Figure 5 shows how the evaluation board can be connected to a voltage source and a voltage meter for some basic output voltage accuracy measurements. A resistor can be used as the load for the regulator. Ensure 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 the voltage source used can supply adequate current for the expected load levels. 4.992 4.990 0 5 10 15 20 VIN (V) Figure 6. ADP1720 Line Regulation Rev. 0 | Page 5 of 8 25 30 EVAL-ADP1720 LOAD REGULATION DROPOUT VOLTAGE For load regulation measurements, the regulator’s output is monitored while the load is varied. For good load regulation, the output must change as little as possible with varying load levels. The input voltage must be held constant during this measurement. The load current can be varied from 0 mA to 50 mA. Figure 7 shows the typical load regulation performance of an ADP1720 with 5 V output for an input voltage of 12 V. Dropout voltage measurements can also be performed using the configuration shown in Figure 5. Dropout voltage is defined as the input-to-output voltage differential when the input voltage is set to the nominal output voltage. This applies only for output voltages above 4 V. Dropout voltage increases with larger loads. For more accurate measurements, a second voltage meter 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 8 shows a typical curve of dropout voltage measurements with different load currents. 5.0015 5.0010 5.0005 300 4.9995 4.9990 250 4.9985 VDROPOUT (mV) 4.9980 4.9975 06768-007 4.9970 4.9965 0.01 0.1 1 10 100 ILOAD (mA) 200 150 100 50 Figure 7. ADP1720 Load Regulation 0 06768-008 VOUT (V) 5.0000 1 10 ILOAD (mA) Figure 8. Dropout Voltage vs. Load Current Rev. 0 | Page 6 of 8 100 EVAL-ADP1720 GROUND CURRENT MEASUREMENTS CURRENT METER _ μA EVAL-ADP1720 + U1 GND C1 GND C2 VOLTAGE SOURCE + R1 _ J1 R2 LOAD VIN VOUT EN GND 06768-009 J2 GND GND/ADJ Figure 9. largest load level (50 mA). Figure 10 shows the typical ground current consumption for various load levels. 1200 1000 800 IGND (µA) Follow these steps to connect to a voltage source and current meter: 1. 2. 3. 4. 5. Connect the positive terminal (+) of the voltage source to the VIN pad on the evaluation board. Connect the positive terminal (+) of the current meter to one of the GND pads of the evaluation board. Connect the negative terminal (−) of the current meter to the negative (−) terminal of the voltage source. Connect a load between the VOUT pad of the evaluation board and the negative (−) terminal of the voltage source. The voltage source can now be turned on. If J1 is inserted (this connects EN to VIN for automatic startup), then the regulator powers up. GROUND CURRENT CONSUMPTION Ground current measurements are a way of determining how much current the regulator’s internal circuits are consuming, while performing the regulation function. To be efficient, the regulator must consume as little current as possible. Typically, the regulator consumes maximum current when supplying its 600 400 200 0 0.01 06768-010 Figure 9 shows how the evaluation board can be connected to a voltage source and a current meter for ground current measurements. A resistor can be used as the load for the regulator. Ensure 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 the voltage source used can supply adequate current for the expected load levels. 0.1 1 10 100 ILOAD (mA) Figure 10. Ground Current vs. Load Current When the device is disabled (EN = 0 V), ground current is reduced to less than 1 μA. Note that larger ground current levels are observed when using an evaluation board with R1 and R2 present. Rev. 0 | Page 7 of 8 EVAL-ADP1720 ORDERING INFORMATION BILL OF MATERIALS Table 2. Qty 1 1 1 1 2 1 Reference Designator C1 C2 R1 R2 J1, J2 U1 Description Capacitor, MLCC, 1 μF, 50 V, 0805, X7R Capacitor, MLCC, 1 μF, 16 V, 0805, X7R Resistor, 15 kΩ, 1%, 0805 Resistor, 10 kΩ, 1%, 0805 Header, single, STR, 2 pins ADP1720, IC, LDO regulator ORDERING GUIDE Model ADP1720-EVALZ1 ADP1720-3.3-EVALZ1 ADP1720-5-EVALZ1 1 Manufacturer/Vendor Murata or equivalent Murata or equivalent Vishay Dale or equivalent Vishay Dale or equivalent Digi-Key, Corp. Analog Devices, Inc. ESD CAUTION Description Evaluation Board with Adjustable Output ADP1720 Evaluation Board with 3.3 V Fixed Output ADP1720 Evaluation Board with 5 V Fixed Output ADP1720 Z = RoHS Compliant Part. ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. EB06768-0-6/07(0) Rev. 0 | Page 8 of 8 Vendor Part No. GRM21BR71H105KA12 GRM21BR71C105KA01 CRCW080515K0FKEA CRCW080510K0FKEA S1012E-36-ND ADP1720ARMZ-5-R7 ADP1720ARMZ-3.3-R7 ADP1720ARMZ-R7