ADP220/ADP221评估板 PDF

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
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