Evaluation Board User Guide
UG-056
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Setting Up the Evaluation Board for the ADP124/ADP125
FEATURES
GENERAL DESCRIPTION
Input voltage range: 2.3 V to 5.5 V
Output current range: 0 mA to 500 mA
Output voltage accuracy: ±1%
Operating temperature range: −40°C to +125°C
This user guide explains the functionality of the ADP124/
ADP125 linear regulators.
Simple device measurements such as line and load regulation,
dropout voltage, and ground current can be achieved with only
a single voltage supply, a voltage meter, a current meter, and
load resistors.
For more information about the ADP124/ADP125 linear
regulators, see the ADP124/ADP125 data sheets.
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
Rev. B | Page 1 of 12
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Evaluation Board User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Line Regulation Measurements ...................................................7
General Description ......................................................................... 1
Load Regulation Measurements ..................................................7
Revision History ............................................................................... 2
Dropout Voltage Measurements..................................................7
Evaluation Board PCB Layout.......................................................... 3
Ground Current Measurements ......................................................8
Evaluation Board Hardware ............................................................ 4
Ground Current Consumption ................................................ 10
Evaluation Board Configurations .............................................. 4
Ordering Information .................................................................... 11
Output Voltage Measurements ....................................................... 5
Bill of Materials for the Evaluation Board .............................. 11
REVISION HISTORY
11/10—Rev. A to Rev. B
Added ADP124 to Figure 9 Caption ...............................................6
Added ADP124 to Figure 15 Caption .............................................9
Changes to U1 Part No. Column, Table 2 ................................... 11
9/10—Rev. 0 to Rev. A
Added LFCSP Throughout................................................ Universal
Changes to Figure 1 and Figure 2, added Figure 3;
Renumbered Sequentially................................................................ 3
Added Figure 6 and changes to Evaluation Board
Configurations Section .................................................................... 4
Changes to Output Voltage Measurements Section..................... 5
Changes to Ground Current Measurements Section................... 8
Added Figure 15................................................................................ 9
Changes to Ordering Information Section ................................. 11
3/10—Revision 0: Initial Version
Rev. B | Page 2 of 12
Evaluation Board User Guide
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Figure 1. ADP124 PCB Layout, MSOP
08525-103
08525-001
EVALUATION BOARD PCB LAYOUT
08525-002
Figure 3. ADP124/ADP125 PCB Layout, LFCSP
Figure 2. ADP125 PCB Layout, MSOP
Rev. B | Page 3 of 12
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Evaluation Board User Guide
EVALUATION BOARD HARDWARE
EVALUATION BOARD CONFIGURATIONS
Table 1. Evaluation Board Hardware Components
The ADP124/ADP125 evaluation boards are supplied with
different components, depending on the version that is ordered.
Components common to both versions are C1, C2, TP1, TP2,
and J1. Figure 4, Figure 5, and Figure 6 show the schematics
of the various ADP124 and ADP125 evaluation board
configurations. Table 1 describes the components.
Component
U1 1
C1
C2
J1
TP1
TP2
TP3
The ADP125 is the same as the ADP124 except that the output
voltage dividers are internally disconnected and the feedback
input of the error amplifiers is brought out for each output. The
output voltage can be set using the following formula:
R1, R2
VOUT = 0.5 V(1 + R1/R2) + (ADJI-BIAS)(R1)
1
The value of R1 should be less than 200 kΩ to minimize errors
in the output voltage caused by the ADJ pin input current. For
example, when R1 and R2 are equal to 200 kΩ, the output voltage
is 1.0 V. The output voltage error introduced by the ADJ pin input
current is 3 mV or 0.30%, assuming a typical ADJ pin input
current of 15 nA at 25°C.
TP2
VOUT
TP1
U1
VIN
C1
VIN 7
2 VOUT
VOUT
SENSE
NC 6
J1
08525-003
3
Component depends on evaluation board type ordered.
VIN 8
1 VOUT
C2
Description
ADP124/ADP125 low dropout linear regulators
Input bypass capacitor, 1 μF, 0603 size
Output capacitor, 1 μF, 0603 size
Jumper (connects EN to VIN for automatic
startup)
Testpoint closer to VIN
Testpoint closer to VOUT
Testpoint closer to ADJ (ADP125 evaluation
board only)
0603 size feedback resistors between VOUT and
ADJ (ADP125 evaluation board only)
EN 5
4 GND
Figure 4. ADP124 MSOP Evaluation Board Schematic
TP2
VOUT
TP1
1 VOUT
C2
U1
R1
TP3
VIN
VIN 8
C1
2 VOUT
VIN 7
3 ADJ
NC 6
4 GND
EN 5
J1
08525-004
R2
Figure 5. ADP125 MSOP Evaluation Board Schematic
TP2
U1
1
1
R1
C2
2
1µF
3
1
VOUT
VIN
VOUT
VIN
VSENSE/ADJ
NC
VIN
8
7
6
C1
1µF
J1
TP3
4
GND
EN
5
1
2
1
1-WAY LINK
ADP124/ADP125
R2
08525-106
VOUT
TP1
Figure 6. ADP124/ADP125 Evaluation Board Schematic, LFCSP
Rev. B | Page 4 of 12
Evaluation Board User Guide
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OUTPUT VOLTAGE MEASUREMENTS
VOLTMETER
VOLTAGE SOURCE
1.99711
+
+
–
–
08525-005
LOAD
Figure 7. ADP124 Output Voltage Measurement Setup, MSOP
VOLTMETER
VOLTAGE SOURCE
1.99711
+
–
LOAD
08525-006
+
–
Figure 8. ADP125 Output Voltage Measurement Setup, MSOP
Rev. B | Page 5 of 12
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Evaluation Board User Guide
VOLTMETER
VOLTAGE SOURCE
1.99711
+
–
–
+
08525-109
LOAD
Figure 9. ADP124/ADP125 Output Voltage Measurement Setup, LFCSP
Figure 7, Figure 8, and Figure 9 show how the evaluation boards
can be connected to a voltage source and a voltage meter for
basic out-put voltage accuracy measurements. 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 that is
expected to dissipate 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.
Follow these steps to connect to a voltage source and voltage meter:
1.
2.
3.
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.
4.
5.
6.
Connect the negative terminal (−) of the voltage meter to
one of the GND pads.
Connect the positive terminal (+) of the voltage meter to
the VOUT pad.
If the ADP124 LFCSP board is being used, short R1.
Otherwise, install R1 and R2 for the ADP125 adjustable
LDO.
When these steps are completed, the voltage source can be turned
on. If J1 is inserted (connecting EN to VIN for automatic startup),
the regulator powers up.
If the load current is large, the user must connect the voltage
meter as close as possible to the output capacitor to reduce the
effects of IR drops.
Rev. B | Page 6 of 12
Evaluation Board User Guide
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3.309
LINE REGULATION MEASUREMENTS
3.308
3.307
VOUT (V)
For example, for the ADP124 with a fixed 3.3 V output, VIN
must be varied between 3.6 V and 5.5 V. This measurement
can be repeated under different load conditions. Figure 10
shows the typical line regulation performance of the ADP124
with a fixed 3.3 V output.
3.306
3.305
3.304
3.303
0.1
1
10
IOUT (mA)
3.310
100
1000
08525-008
For line regulation measurements, the output of the regulator
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 VOUTNOM + 0.3 V
(or 2.3 V, whichever is greater) and VINMAX.
Figure 11. Output Voltage (VOUT) vs. Load Current (IOUT) at VIN = 3.6 V, VOUT =
3.3 V, TA = 25°C
3.308
3.306
DROPOUT VOLTAGE MEASUREMENTS
Dropout voltage can be measured using the configurations
shown in Figure 7, Figure 8, and Figure 9. 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 to output voltages above 2.3 V. Dropout voltage increases
with larger loads.
3.302
3.300
3.298
3.296
IOUT = 100µA
IOUT = 1mA
IOUT = 10mA
IOUT = 100mA
IOUT = 300mA
IOUT = 500mA
3.292
3.50
4.00
4.50
5.00
5.50
VIN (V)
08525-007
3.294
Figure 10. Output Voltage (VOUT) vs. Input Voltage (VIN) at TA = 25°C
LOAD REGULATION MEASUREMENTS
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 12
shows the typical curve of dropout voltage measurements with
different load currents.
For load regulation measurements, the output of the regulator
is monitored while the load is varied. For good load regulation,
the output must change as little as possible with varying load.
The input voltage must be held constant during this measurement. The load current can be varied from 0 mA to 500 mA.
120
DROPOUT (mV)
100
Figure 11 shows the typical load regulation performance of the
ADP124 with a fixed 3.3 V output for an input voltage of 3.6 V.
80
60
40
20
0
1
10
100
IOUT (mA)
1000
08525-009
VOUT (V)
3.304
Figure 12. Dropout Voltage vs. Load Current (IOUT) at VOUT = 3.3 V, TA = 25°C
Rev. B | Page 7 of 12
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Evaluation Board User Guide
GROUND CURRENT MEASUREMENTS
VOLTAGE SOURCE
–
+
AMMETER
0.00112
+
LOAD
08525-010
–
Figure 13. ADP124 Ground Current Measurement Setup, MSOP
VOLTAGE SOURCE
–
+
AMMETER
0.00112
+
LOAD
Figure 14. ADP125 Ground Current Measurement Setup, MSOP
Rev. B | Page 8 of 12
08525-011
–
Evaluation Board User Guide
AMMETER
UG-056
VOLTAGE SOURCE
0.00112
–
–
+
LOAD
08525-015
+
Figure 15. ADP124/ADP125 Ground Current Measurement Setup, LFCSP
Rev. B | Page 9 of 12
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Evaluation Board User Guide
Figure 13, Figure 14, and Figure 15 show how the evaluation
boards 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 that is adequate to handle the power that is expected to
dissipate across it. An electronic load can be used as an
alternative. Ensure that the voltage source can supply enough
current for the expected load levels.
GROUND CURRENT CONSUMPTION
Follow these steps to connect to a voltage source and ammeter:
When the device is disabled (EN = GND), the ground current
drops to less than 1 μA.
3.
4.
5.
250
IOUT = 500mA
230
210
190
150
130
IOUT = 100mA
110
90
When these steps are completed, the voltage source can be turned
on. If J1 is inserted (connecting EN to VIN for automatic startup),
the regulator powers up.
IOUT = 300mA
170
IOUT = 10mA
IOUT = 1mA
IOUT = 100µA
70
50
3.50
4.00
4.50
VIN (V)
5.00
5.50
08525-012
2.
Connect the positive terminal (+) of the voltage source to
the VIN pad of the evaluation board.
Connect the positive terminal (+) of the ammeter to one
of the GND pads on the evaluation board.
Connect the negative terminal (−) of the ammeter 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.
If the ADP124 LFCSP board is being used, short R1.
Otherwise, install R1 and R2 for the ADP125 adjustable
LDO.
GROUND CURRENT (µA)
1.
Ground current measurements can determine how much current
the internal circuits of the regulator consume while the circuits
perform the regulation function. To be efficient, the regulator
must consume as little current as possible. Typically, the regulator
uses the maximum current when supplying its largest load level
(500 mA). Figure 16 shows the typical ground current consumption
for various load levels at VOUT = 3.3 V and TA = 25°C.
Figure 16. Ground Current vs. Input Voltage (VIN) at VOUT = 3.3 V, TA = 25°C
Rev. B | Page 10 of 12
Evaluation Board User Guide
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ORDERING INFORMATION
BILL OF MATERIALS FOR THE EVALUATION BOARD
Table 2.
Reference Designator
C1, C2
R1, R2 (ADP125 only)
J1
U1
Description
Capacitor, MLCC, 1 μF, 16 V, 0603, X5R
100 kΩ 0603 size resistors
Jumper, single, STR, two pins
IC, LDO regulator
Manufacturer
Murata (or equivalent)
Vishay
Sullins Connector Solutions
Analog Devices, Inc.
Rev. B | Page 11 of 12
Part No.
GRM188R61C105KA93
CRCW06031003F
PEC02SAAN
ADP124ARHZ-3.3-R7
ADP125ARHZ-R7
ADP124ACPZ-3.3-R7
ADP125ACPZ-R7
UG-056
Evaluation Board User Guide
NOTES
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.
©2010 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
UG08525-0-11/10(B)
Rev. B | Page 12 of 12
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