ADP2389-EVALZ/ADP2390-EVALZ User Guide
UG-863
One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Evaluating the ADP2389/ADP2390, 18 V, 12 A Step-Down Regulators with
Programmable Current Limit
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | Page 1 of 8
FEATURES
Input voltage: 4.5 V to 18 V
Continuous output current: 12 A
Integrated MOSFET: 17 mΩ/4.5 mΩ
Reference voltage: 0.6 V ±0.5%
Programmable switching frequency: 200 kHz to 2.2 MHz
Enhanced transient response
Programmable current-limit with ±10% accuracy
Precision enable and power good
External compensation and soft start
PFM mode (ADP2390 only)
Start up into a precharged output
Supported by ADIsimPowerTM design tool
GENERAL DESCRIPTION
The ADP2389/ADP2390 evaluation board is a complete, 12 A,
18 V, step-down regulator solution that allows users to evaluate
the performance of the ADP2389/ADP2390 with a near ideal
printed circuit board (PCB) layout.
The programmable current-limit function allows the inductor
to be optimized by output current. The peak current-limit
threshold is preset to 16.8 A to ensure the 12 A output current
capability.
The switching frequency can be programmed between 200 kHz
and 2.2 MHz, which provides the possibility for a stackable
multiphase power solution.
An enhanced transient response feature improves the load
transient performance, which reduces the output capacitance.
The output of the ADP2389/ADP2390 evaluation board is
preset to 1.8 V and the switching frequency is set to 500 kHz.
Different output voltage settings can be achieved by changing
appropriate passive components. The ambient temperature
operating range is −40°C to +85°C.
Full details on the ADP2389/ADP2390 regulators are provided
in the ADP2389/ADP2390 data sheet, available from Analog
Devices, Inc., which should be consulted in conjunction with
this user guide.
EVALUATION BOARD PHOTOGRAPH
13375-001
Figure 1.
UG-863 ADP2389-EVALZ/ADP2390-EVALZ User Guide
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TABLE OF CONTENTS
Features .............................................................................................. 1
General Description ......................................................................... 1
Evaluation Board Photograph ......................................................... 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Power Supplies .............................................................................. 3
Measuring Evaluation Board Performance ...................................3
Modifying the Board .....................................................................4
Evaluation Board Schematic and Artwork .....................................5
Ordering Information .......................................................................7
Bill of Materials ..............................................................................7
REVISION HISTORY
9/15—Revision 0: Initial Version
ADP2389-EVALZ/ADP2390-EVALZ User Guide UG-863
Rev. 0 | Page 3 of 8
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The ADP2389/ADP2390 evaluation board is provided fully
assembled and tested. Before applying power to the evaluation
board, follow the procedures in this section.
Jumper J5 (Enable)
Use one of the following methods to enable or to disable the
regulator:
• To enable the regulator, short the middle pin of J5, EN,
to high.
• To disable the regulator, short the middle pin of J5, EN,
to low.
Input Power Source
If the input power source includes a current meter, use that meter
to monitor the input current. Connect the positive terminal
of the power source to J7 (PVIN) of the evaluation board, and
the negative terminal of the power source to J14 (GND) of the
evaluation board.
If the power source does not include a current meter, connect a
current meter in series with the input source voltage. Connect the
positive lead (+) of the power source to the positive (+) ammeter
terminal, the negative lead (−) of the power source to J14
(GND), and the negative lead (−) of the ammeter to J7 (PVIN).
Output Load
Prior to connecting the load, ensure that the evaluation board is
turned off. Connect an electronic load or resistor to the output
of the evaluation board to set the load current.
Connect the positive terminal of the load to J12 (VOUT) of the
evaluation board and connect the negative terminal of the load to
J15 (GND).
Input and Output Voltmeters
Measure the input and output voltages using voltmeters. Ensure
that the voltmeters are connected to the appropriate terminals of
the evaluation board and not to the load or power source. If the
voltmeters are not connected directly to the evaluation board, it
produces incorrect measured voltages because the voltage drops
across the leads or connections between the evaluation board,
the power source, and the load.
To measure the input voltage, connect the positive terminal of the
voltmeter to J9 (PVIN_SNS) and the negative terminal to J13
(GND_SNS). Likewise, to measure the output voltage, connect
the positive terminal of the voltmeter to J11 (VOUT_SNS) and
the negative terminal to J16 (GND_SNS).
Turning On the Evaluation Board
When the power source and load are connected to the evaluation
board, it can be powered for operation.
Perform the following steps to turn on the board:
1. Ensure that the power source voltage is >4.5 V and <18 V.
2. Ensure that EN is high and monitor the output voltage.
3. Turn on the load, check that it is drawing the proper load
current, and verify that the output voltage maintains its
regulation.
MEASURING EVALUATION BOARD PERFORMANCE
Measuring the Switching Waveform
To observe the switching waveform with an oscilloscope, place the
oscilloscope probe tip at Tes t Point J3 (SW) with the probe ground
at J1 (GND). Set the scope to dc with the appropriate voltage and
time divisions. Alternate the switching waveform limits between
~0 V and the input voltage.
Measuring Load Regulation
Measure the load regulation by observing the change in the
output voltage while increasing the output load current. To
minimize the voltage drop, use short, low resistance wires.
Measuring Line Regulation
Measure the line regulation by varying the input voltage and
examining the change in the output voltage with a fixed output
current.
Line Transient Response
To test the line transient response, generate a step input voltage
change and observe the behavior of the output voltage using an
oscilloscope.
Load Transient Response
To test the load transient response, generate a load current
transient at the output and observe the output voltage response
using an oscilloscope. Attach the current probe to the wire
between the output and the load to capture the current transient
waveform.
Measuring Efficiency
The efficiency, η, is measured by comparing the input power with
the output power.
ININ
OUTOUT
IV
IV
η×
×
=
Measure the input and output voltages as close as possible to the
input and output capacitors to reduce the effect of voltage drop.
Measuring Inductor Current
To measure the inductor current, remove one end of the
inductor from its pad and connect a current loop in series with the
inductor end and its pad (acurrent probe can be connected onto
this wire).
UG-863 ADP2389-EVALZ/ADP2390-EVALZ User Guide
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Measuring Output Voltage Ripple
To observe the output voltage ripple, place the oscilloscope probe
across the output capacitor with the probe ground lead connected
to the negative (−) capacitor terminal and the probe tip placed at
the positive (+) capacitor terminal. Set the oscilloscope to ac,
10 mV/division, 2 µs/division time base, and 20 MHz bandwidth.
A standard oscilloscope probe has a long wire ground clip. For
high frequency measurements, this ground clip picks up high
frequency noise and injects it into the measured output ripple.
Figure 2 shows an easy way to measure the output ripple properly.
It requires removing the oscilloscope probe sheath and wrapping
an unshielded wire around the oscilloscope probe. By keeping
the ground length of the oscilloscope probe as short as possible,
the true ripple can be measured.
13375-002
Figure 2. Measuring Output Voltage Ripple
MODIFYING THE BOARD
To modify the ADP2389/ADP2390 evaluation board configura-
tion, unsolder and/or replace or remove the appropriate passive
components or jumpers on the board.
Changing the Output Voltages
The output voltage setpoints of the ADP2389/ADP2390 can be
changed by replacing the R9 and R5 resistors with the resistor
values shown in Table 1.
Table 1. Resistive Divider for Various Output Voltages
V
OUT
(V)
R9, ±1% (kΩ)
R5, ±1% (kΩ)
1.0
10
15
1.2
10
10
1.5
15
10
1.8
20
10
2.5 47.5 15
3.3
10
2.21
5.0
22
3
To limit output voltage accuracy degradation due to the FB pin
bias current (0.1 µA maximum) to less than 0.5% (maximum),
ensure that the bottom divider string resistor, R5, is less than
30 kΩ.
The top resistor, R9, value is calculated using the following
equation:
−
×=
V6.0
V6.0
OUT
V
R5R9
When the output voltage is changed, the values of the inductor
(L1), the output capacitors (C13, C14, C15, C16, and C17), and
the compensation components (R10, C5, and C4) must be
recalculated and changed to ensure stable operation (see the
ADP2389/ADP2390 data sheet for details on external component
selection).
Changing the Switching Frequency
The switching frequency (fSW) setpoint can be changed by
replacing the R6 resistor with a different value, as shown in
the following equation:
fSW (kHz) = 67,000/(R6 (kΩ) +12)
A 210 kΩ resistor sets the frequency to 300 kHz, and a 100 kΩ
resistor sets the frequency to 600 kHz.
When the switching frequency is changed, the values of the
inductor (L1), the output capacitors (C13, C14, C15, C16,
and C17), and the compensation networks (R10, C5, and C4)
must be recalculated and changed for stable operation (see
the ADP2389/ADP2390 data sheet for details on external
component selection).
Changing the Soft Start Time
The soft start time of the ADP2389/ADP2390 on the evaluation
board is programmed to 4 ms.
To change the soft start time, tSS, replace the C3 capacitor value
using the following equation:
C3 (nF) = 5.67 × tSS (ms)
Changing the Peak Current-Limit Threshold
The peak current-limit threshold of ADP2389/ADP2390 can be
changed by replacing the R7 resistor with a different value, as
shown in the following equation:
IOCP (A) = 1000/(R7 (kΩ) + 0.5)
A 54.9 kΩ resistor sets the current-limit threshold to 18 A, an
82.5 kΩ resistor sets the current-limit threshold to 12 A, and a
110 kΩ resistor sets the current-limit threshold to 9 A.
By programming the peak current-limit threshold at different
levels, the value and size of the inductor (L1) can be optimized
based on actual applications.
ADP2389-EVALZ/ADP2390-EVALZ User Guide UG-863
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EVALUATION BOARD SCHEMATIC AND ARTWORK
Figure 3. Evaluation Board Schematic for ADP2389/ADP2390
UG-863 ADP2389-EVALZ/ADP2390-EVALZ User Guide
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13375-004
Figure 4. Layer 1, Component Side
13375-006
Figure 5. Layer 2, Ground Plane
13375-005
Figure 6. Layer 3, Power Plane
13375-007
Figure 7. Layer 4, Bottom Side
ADP2389-EVALZ/ADP2390-EVALZ User Guide UG-863
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ORDERING INFORMATION
BILL OF MATERIALS
Table 2. ADP2389 Bill of Materials
Qty. Reference Designator Description Part Number/Vendor
2 C1, C7 0.1 µF, 16 V, capacitor, 0603 GRM188R71C104KA01D/Murata
2 C2, C18 Optional, capacitor, 0603 Optional/Murata
1 C3 22 nF, 16 V, capacitor, 0603 GRM188R71C223KA01D/Murata
1 C4 22 pF, 50 V, capacitor, 0603 GRM1885C1H220JA01D/Murata
1 C5 1.5 nF, 25 V, capacitor, 0603 GRM188R71E152KA01D/Murata
1 C6 1 µF, 16 V, capacitor, 0603 GRM188R61C105KA93D/Murata
5 C8, C9, C10, C11, C12 10 µF, 25 V, capacitor, 1206 GRM31CR61E106MA12L/Murata
5 C13, C14, C15, C16, C17 100 µF, 6.3 V, capacitor, 1210 GRM32ER60J107ME20L/Murata
1 L1 Inductor, 7443320100, L = 1 µH, ISAT = 32 A,
DCR = 1.17 mΩ
7443320100/Würth Elektronik
4 R1, R3, R4, R8 Optional, resistor, 0603 Optional/Vishay Dale
2 R2, R5 10 kΩ, 1%, resistor, 0603 CRCW060310K0FKEA/Vishay Dale
1 R6 121 kΩ, 1%, resistor, 0603 CRCW0603121KFKEA/Vishay Dale
1 R7 59 kΩ, 1%, resistor, 0603 CRCW060359K0FKEA /Vishay Dale
1 R9 20 kΩ, 1%, resistor, 0603 CRCW060320K0FKEA/Vishay Dale
1 R10 27.4 kΩ, 1%, resistor, 0603 CRCW060327K4FKEA/Vishay Dale
1 R11 0 Ω, 0.1 W, resistor, 0603 CRCW06030000Z0EA/Vishay Dale
1 R12 6.8 Ω, 1%, resistor, 0603 CRCW06036R80FKEA/Vishay Dale
1 U1 18 V, 12 A, synchronous, step-down regulator,
32-lead, LFCSP_VQ, with exposed paddles
ADP2389/Analog Devices, Inc.
11 J1, J2, J3, J4, J6, J8, J9, J10, J11, J13, J16 Test point, 2.54 mm pitch SIL vertical PC tail pin
header, 6.1 mm mating pin height, tin, SIP1
M20-9990245/Harwin
1 J5 Jumper, 0.1-inch header, three-way, SIP3 M20-9990346/Harwin
4 J7, J12, J14, J15 Terminal screw vertical PC mount 8191/Keystone Electronics
UG-863 ADP2389-EVALZ/ADP2390-EVALZ User Guide
Rev. 0 | Page 8 of 8
Table 3. ADP2390 Bill of Materials
Qty. Reference Designator Description Part Number/Vendor
2 C1, C7 0.1 μF, 16 V, capacitor, 0603 GRM188R71C104KA01D/Murata
2 C2, C18 Optional, capacitor, 0603 Optional/Murata
1 C3 22 nF, 16 V, capacitor, 0603 GRM188R71C223KA01D/Murata
1 C4 22 pF, 50 V, capacitor, 0603 GRM1885C1H220JA01D/Murata
1 C5 1.5 nF, 25 V, capacitor, 0603 GRM188R71E152KA01D/Murata
1 C6 1 μF, 16 V, capacitor, 0603 GRM188R61C105KA93D/Murata
5 C8, C9, C10, C11, C12 10 μF, 25 V, capacitor, 1206 GRM31CR61E106MA12L/Murata
5 C13, C14, C15, C16, C17 100 μF, 6.3 V, capacitor, 1210 GRM32ER60J107ME20L/Murata
1 L1 Inductor, 7443320100, L = 1 μH, ISAT = 32 A,
DCR = 1.17 mΩ
7443320100/Würth Elektronik
4 R1, R3, R4, R8 Optional, resistor, 0603 Optional/Vishay Dale
2 R2, R5 10 kΩ, 1%, resistor, 0603 CRCW060310K0FKEA/Vishay Dale
1 R6 121 kΩ, 1%, resistor, 0603 CRCW0603121KFKEA/Vishay Dale
1 R7 59 kΩ, 1%, resistor, 0603 CRCW060359K0FKEA /Vishay Dale
1 R9 20 kΩ, 1%, resistor, 0603 CRCW060320K0FKEA/Vishay Dale
1 R10 27.4 kΩ, 1%, resistor, 0603 CRCW060327K4FKEA/Vishay Dale
1 R11 0 Ω, 0.1 W, resistor, 0603 CRCW06030000Z0EA/Vishay Dale
1 R12 6.8 Ω, 1%, resistor, 0603 CRCW06036R80FKEA/Vishay Dale
1 U1 18 V, 12 A, synchronous, step-down regulator,
32-lead, LFCSP_VQ, with exposed paddles
ADP2390/Analog Devices, Inc.
11 J1, J2, J3, J4, J6, J8, J9, J10, J11, J13, J16 Test point, 2.54 mm pitch SIL vertical PC tail pin
header, 6.1 mm mating pin height, tin, SIP1
M20-9990245/Harwin
1 J5 Jumper, 0.1-inch header, 3-way, SIP3 M20-9990346/Harwin
4 J7, J12, J14, J15 Terminal screw vertical PC mount 8191/Keystone Electronics
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
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TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL
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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
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UG13375-0-9/15(0)