Evaluation Board for the ADP121
EVAL-ADP121
Rev. A
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 ©2008–2009 Analog Devices, Inc. All rights reserved.
FEATURES
Input voltage range: 2.3 V to 5.5 V
Output current range: 0 mA to 150 mA
Output voltage accuracy: ±1%
Operating temperature range: −40°C to +125°C
GENERAL DESCRIPTION
The ADP121 evaluation boards are used to demonstrate the
functionality of the ADP121 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 ADP121 linear regulators, see the
ADP121 data sheet.
EVALUATION BOARD BLOCK DIAGRAMS
VIN VOUT
GND
EN
GND
GNDGND
07140-001
C2C1 U1
J1
ANALOG DEVICES
ADP121-xx-EVALZ
NOTES
1. xx = 28 (2.8V), 30 (3.0V), 33 (3.3V).
Figure 1. TSOT
07140-014
Figure 2. WLCSP
EVAL-ADP121
Rev. A | Page 2 of 8
TABLE OF CONTENTS
Features .............................................................................................. 1
General Description ......................................................................... 1
Evaluation Board Block Diagrams ................................................. 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Evaluation Board Configurations .............................................. 3
Measuring Output Voltage .............................................................. 4
Line Regulation ............................................................................. 5
Load Regulation ............................................................................5
Dropout Voltage ............................................................................5
Measuring Ground Current .............................................................6
Ground Current Consumption ...................................................7
Ordering Information .......................................................................8
Bill of Materials ..............................................................................8
Ordering Guide .............................................................................8
ESD Caution...................................................................................8
REVISION HISTORY
4/09—Rev. 0 to Rev. A
Changes to Figure 2 .......................................................................... 1
Changes to Figure 5 and Figure 6 ................................................... 4
Changes to Figure 12 ........................................................................ 6
Changes to Ordering Guide ............................................................ 8
7/08—Revision 0: Initial Version
EVAL-ADP121
Rev. A | Page 3 of 8
EVALUATION BOARD HARDWARE
EVALUATION BOARD CONFIGURATIONS
The EVAL-ADP121 is supplied with different components
depending on which version is ordered. Components common
to all versions are C1, C2, and J1 or J2. Figure 3 and Figure 4
show schematics for these evaluation board configurations.
1
2
3
5
4
140-00207
C2
C1 J1
V
OUT
V
IN
VOUT
NC
VIN
GND
EN
U1
Figure 3. Evaluation Board Circuit Diagram, TSOT
J2
C1 C2
V
IN
V
OUT
VIN VOUT
U1
07140-010
EN GND
Figure 4. Evaluation Board Circuit Diagram, WLCSP
Table 1. Evaluation Board Hardware Components
Component Function Description
U11 Linear
regulator
ADP121 low dropout linear
regulator.
C1 Input
capacitor
1 μF input bypass capacitor.
C2 Output
capacitor
1 μF output capacitor. Required for
stability and transient performance.
J1 or J2 Jumper Jumper. Connects EN to IN for
automatic startup.
1 This component varies depending on the evaluation board type ordered.
EVAL-ADP121
Rev. A | Page 4 of 8
MEASURING OUTPUT VOLTAGE
GNDGND
ANALOG DEVICES
ADP121-xx-EVALZ
VOUT
GND
C2C1 U1
VIN
GND EN
J1
VOLT AG E S OURCE
07140-003
VOLTMETER
LOAD
+–
+–
Figure 5. Output Voltage Measurement, TSOT
07140-015
VOLTMETER
+–
+–
VOLTAGE S O URCE
LOAD
Figure 6. Output Voltage Measurement, WLCSP
Figure 5 and Figure 6 show how the evaluation board can be
connected to a voltage source and a voltmeter 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.
Ensure that the voltage source can supply enough current for
the expected load levels.
Use the following steps to connect to a voltage source and
voltmeter:
1. Connect the negative terminal (−) of the voltage source to
one of the GND pads on the evaluation board.
2. Connect the positive terminal (+) of the voltage source to
the VIN pad of the evaluation board.
3. Connect a load between the VOUT pad and one of the
GND pads.
4. Connect the negative terminal (−) of the voltmeter to one
of the GND pads.
5. Connect the positive terminal (+) of the voltmeter to the
VOUT pad.
The voltage source can now be turned on. If J1 or J2 is inserted
(connecting EN to VIN for automatic startup), the regulator
powers up.
If the load current is large, the user needs to connect the
voltmeter as close as possible to the output capacitor to
reduce the effects of IR drops.
EVAL-ADP121
Rev. A | Page 5 of 8
LINE REGULATION
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 that the device is not in dropout mode during
this measurement, VIN must be varied between VOUT nominal
+ 0.5 V (or 2.3 V, whichever is greater) and VIN maximum. For
example, an ADP121 with a fixed 1.8 V output needs VIN to be
varied between 2.3 V and 5.5 V. This measurement can be
repeated under different load conditions. Figure 7 shows the
typical line regulation performance of the ADP121 with fixed
1.8 V output.
07140-004
1.806
1.802
1.804
1.800
1.796
1.794
1.798
V
OUT
(V)
2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
V
IN
(V)
V
OUT
= 1. 8V
T
A
= 25°C
LO AD = 10µ A
LO AD = 100µ A
LO AD = 1mA
LO AD = 10mA
LO AD = 50mA
LO AD = 100mA
Figure 7. Output Voltage vs. Input Voltage
LOAD REGULATION
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 loads.
The input voltage must be held constant during this measure-
ment. The load current can be varied from 0 mA to 150 mA.
Figure 8 shows the typical load regulation performance of the
ADP121 with fixed 1.8 V output for an input voltage of 2.3 V.
1.806
1.804
1.802
1.800
1.798
1.796
1.794
0.01 0.1 1 10 100 1000
ILOAD (mA)
VOUT (V)
07140-005
VOUT = 1.8V
VIN = 2.3V
TA = 25°C
Figure 8. Output Voltage vs. Load Current
DROPOUT VOLTAGE
Dropout voltage can be measured using the configuration
shown in Figure 5 and Figure 6. 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 2.3 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 9 and
Figure 10 show the typical curves of dropout voltage measure-
ments with different load currents for different output voltages.
120
140
160
180
100
80
60
40
20
01 10 100 1000
I
LOAD
(mA)
V
DROPOUT
(mV)
07140-006
T
A
= 25°C
V
OUT
= 3. 3V
V
OUT
= 2. 5V
Figure 9. TSOT Dropout Voltage vs. Load Current
100
80
60
40
140
120
20
01 10 100 1000
I
LOAD
(mA)
V
DROPOUT
(mV)
07140-013
T
A
= 25°C
V
OUT
= 3. 3V
V
OUT
= 2. 5V
Figure 10. WLCSP Dropout Voltage vs. Load Current
EVAL-ADP121
Rev. A | Page 6 of 8
MEASURING GROUND CURRENT
07140-007
GNDGND
ANALOG DEVICES
ADP121-xx-EVALZ
VOUT
GND
C2C1 U1
VIN
GND EN
J1
VOLT AGE SOURCE
LOAD
AMMETER
+– +–
Figure 11. Ground Current Measurement, TSOT
07140-016
LOAD
AMMETER
+–
+–
VOLT AGE SO URCE
Figure 12. Ground Current Measurement, WLCSP
Figure 11 and Figure 12 show the evaluation board connected
to a voltage source and an ammeter for ground current measure-
ments. A resistor can be used as the load for the regulator.
Ensure that the resistor has a power rating that is 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.
Use the following steps to connect to a voltage source and
ammeter:
1. Connect the positive terminal (+) of the voltage source to
the VIN pad on the evaluation board.
2. Connect the positive terminal (+) of the ammeter to one of
the GND pads of the evaluation board.
3. Connect the negative terminal (−) of the ammeter to the
negative (−) terminal of the voltage source.
4. Connect a load between the negative (−) terminal of the
voltage source and the VOUT pad of the evaluation board.
The voltage source can now be turned on. If J1 or J2 is inserted
(connecting EN to VIN for automatic startup), the regulator
powers up.
EVAL-ADP121
Rev. A | Page 7 of 8
GROUND CURRENT CONSUMPTION
Ground current measurements can determine how much current
the regulator’s internal circuits consume while the circuits
perform the regulation function. To be efficient, the regulator
needs to consume as little current as possible. Typically, the regu-
lator uses the maximum current when supplying its largest load
level (150 mA). Figure 13 shows the typical ground current
consumption for various load levels at an input voltage of 2.3 V.
When the device is disabled (EN = GND), the ground current
drops to less than 1 μA.
35
30
25
20
15
10
5
0
0.01 0.1 1 10 100 1000
I
LOAD
(mA)
GRO UND CURRENT (µ A)
07140-008
V
OUT
= 1. 8V
V
IN
= 2. 3V
T
A
= 25°C
Figure 13. Ground Current vs. Load Current
EVAL-ADP121
Rev. A | Page 8 of 8
ORDERING INFORMATION
BILL OF MATERIALS
Table 2.
Qty Reference Designator Description Manufacturer/Vendor Vendor Part No.
2 C1, C2 Capacitor, MLCC, 1 μF, 10 V, 0402, X5R Murata or equivalent GRM155R61A105KE15
1 J1 or J2 Header, single, STR, 2 pins Digi-Key Corp. S1012E-36-ND
1 U1 IC, LDO regulator Analog Devices, Inc. ADP121-AUJZ33R7
ADP121-AUJZ30R7
ADP121-AUJZ28R7
ADP121-ACBZ33R7
ADP121-ACBZ30R7
ADP121-ACBZ28R7
ADP121-ACBZ20R7
ADP121-ACBZ18R7
ORDERING GUIDE
Model Output Voltage Description
ADP121-3.3-EVALZ1 3.3 ADP121 3.3 V Output Evaluation Board [TSOT]
ADP121-3.0-EVALZ1 3.0 ADP121 3.0 V Output Evaluation Board [TSOT]
ADP121-2.8-EVALZ1 2.8 ADP121 2.8 V Output Evaluation Board [TSOT]
ADP121-1.8-EVALZ1 1.8 ADP121 1.8 V Output Evaluation Board [TSOT]
ADP121-1.5-EVALZ1 1.5 ADP121 1.5 V Output Evaluation Board [TSOT]
ADP121-1.2-EVALZ1 1.2 ADP121 1.2 V Output Evaluation Board [TSOT]
ADP121CB-3.3-EVALZ1 3.3 ADP121-1 3.3 V Output Evaluation Board [WLCSP]
ADP121CB-3.0-EVALZ1 3.0 ADP121-1 3.0 V Output Evaluation Board [WLCSP]
ADP121CB-2.8-EVALZ1 2.8 ADP121-1 2.8 V Output Evaluation Board [WLCSP]
ADP121CB-2.0-EVALZ1 2.0 ADP121-1 2.0 V Output Evaluation Board [WLCSP]
ADP121CB-1.8-EVALZ1 1.8 ADP121-1 1.8 V Output Evaluation Board [WLCSP]
ADP121CB-1.5-EVALZ1 1.5 ADP121 1.5 V Output Evaluation Board [WLCSP]
ADP121CB-1.2-EVALZ1 1.2 ADP121 1.2 V Output Evaluation Board [WLCSP]
ADP121-BL1-EVZ1 Blank Evaluation Board
1 Z = RoHS Compliant Part.
ESD CAUTION
©2008–2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
EB07140-0-4/09(A)
