B:ADP1864-EVALZ:ADP1864评估板和网络设计工具数据手册  PDF

Evaluation Board for ADP1864
with Web Design Tool
EVAL-ADP1864
FEATURES
EVALUATION BOARD DESCRIPTION
Powerful companion design tool for quick design times
Input voltage range: 3.15 V to 14 V
Output voltage range: 0.8 V to VIN
Output current: up to 10 A
Accommodating layout with multiple packages for diodes,
PFETs, input and output capacitors, and inductors
3 PFETs in parallel for high current applications
Programmable compensation for optimizing transient
performance
Programmable current limit with sense resistor(s)
Enable/shutdown logic
Switching frequency: 580 kHz
Kelvin connections for measuring input and output voltage
The ADP1864 evaluation board is designed to be used with the
ADP1864 Buck Design Software. The evaluation board is configured to provide 3.3 V output at 3 A over an input voltage range
of 9 V to 12 V. Through a versatile layout that accommodates
several packages and a powerful companion design tool, the
ADP1864 evaluation board can provide a wide variety of solutions,
including up to a 5.0 V output at 10 A from a 12 V input. Kelvin
connection terminals provide an accurate means for measuring
the input and output voltages.
SHIPPED CONFIGURATION
Fully populated ADP1864-EVALZ
Input voltage range: 9 V to 12 V
Output voltage: 3.3 V
Output current: 3 A
Bare board ADP1864-BL-EVALZ
Populated with only ADP1864
The evaluation board is designed to use the ADP1864 as an
asynchronous, step-down dc-to-dc converter that uses a current
mode pulse-width modulation control scheme. The ADP1864
drives a P-channel MOSFET that regulates an output voltage as
low as 0.8 V with ±1.25% accuracy (up to 85°C), for up to 10 A
load currents, from input voltages as high as 14 V. The ADP1864
provides system flexibility by allowing accurate setting of the
current limit with an external resistor, while the output voltage
is easily adjustable using two external resistors.
For more details, see the ADP1864 data sheet.
05612-016
EVALUATION BOARD PHOTO
Figure 1. ADP1864-EVALZ
Rev. C
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 ©2006–2009 Analog Devices, Inc. All rights reserved.
EVAL-ADP1864
TABLE OF CONTENTS
Features .............................................................................................. 1 Enter Performance Specifications ...............................................8 Shipped Configuration .................................................................... 1 Select Component Values and Sizes ...........................................9 Evaluation Board Description......................................................... 1 Power Dissipation and Temperature ..........................................9 Evaluation Board Photo ................................................................... 1 Efficiency ........................................................................................9 Revision History ............................................................................... 2 Application Schematic ..................................................................9 Powering the Evaluation Board ...................................................... 3 BOM Summary .............................................................................9 Input Power Source ...................................................................... 3 Modifying the Evaluation Board .................................................. 10 Output Load .................................................................................. 3 Changing the MOSFET ............................................................. 10 Input and Output Voltmeters...................................................... 3 Changing the Sense Resistor ..................................................... 10 Turning On the Evaluation Board .............................................. 3 Changing the Diode ................................................................... 10 Measuring the Performance of the Evaluation Board ................. 4 Changing the Output Inductor ................................................ 10 Measuring Output Voltage Ripple.............................................. 4 Changing the Output Capacitors ............................................. 10 Measuring the Switching Waveform .......................................... 4 Changing the Output Voltage ................................................... 11 Measuring the Gate-to-Source Waveform ................................ 4 Schematic ......................................................................................... 12 Measuring the Inductor Current ................................................ 4 Assembly Drawing ......................................................................... 13 Measuring Efficiency and Load Regulation.............................. 4 Ordering Information .................................................................... 14 Measuring Line Regulation ......................................................... 4 Bill of Materials ........................................................................... 14 Monitoring Short-Circuit Behavior ........................................... 4 Ordering Guide .......................................................................... 14 Typical Performance Characteristics ............................................. 5 ESD Caution................................................................................ 14 Excel Design Tool Interface ............................................................. 8 REVISION HISTORY
7/09—Rev. B to Rev. C
Changes to Changing the Output Voltage Section, Equation .. 11
6/07—Rev. 0 to Rev. A
4/06—Revision 0: Initial Version
6/08—Rev. A to Rev. B
Changes to Shipped Configuration Section .................................. 1
Changes to Figure 1 .......................................................................... 1
Changes to Powering the Evaluation Board Section ................... 3
Changes to Figure 3 Caption ........................................................... 4
Changes to Excel Design Tool Interface Section Heading .......... 8
Changes to Figure 18 Caption......................................................... 8
Changes to BOM Summary Section .............................................. 9
Changes to Changing the Output Capacitors Section ............... 10
Changes to Figure 19 ...................................................................... 12
Added Figure 20 and Figure 21..................................................... 13
Changes to Table 1 .......................................................................... 14
Added Table 2.................................................................................. 14
Changes to Ordering Guide .......................................................... 14
Rev. C | Page 2 of 16
EVAL-ADP1864
POWERING THE EVALUATION BOARD
The ADP1864 evaluation board is supplied fully assembled or,
optionally, populated with only the ADP1864 IC. Before
applying power to the evaluation board, refer to Figure 2 and
follow the procedures in this section.
ammeter terminal to the evaluation board VOUT terminal, the
negative (−) ammeter terminal to the positive (+) load terminal,
and the negative (−) load terminal to the evaluation board GND
terminal just above the VOUT terminal.
INPUT POWER SOURCE
After the load is connected, make sure that it is set to the proper
current before powering the ADP1864 evaluation board.
Before connecting the power source to the ADP1864 evaluation
board, make sure that it is turned off. 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
the VIN terminal on the evaluation board, and the negative
terminal of the power source to the GND terminal just below
the VIN terminal. 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
ammeter positive (+) connection, the negative lead (−) of the
power source to the GND terminal just below the VIN terminal
on the evaluation board, and the negative lead (−) of the
ammeter to the VIN terminal on the board.
OUTPUT LOAD
Although the ADP1864 evaluation board can sustain the sudden
connection of the load, it is possible to damage the load if it is
not properly connected. Make sure that the board is turned off
before connecting the load. If the load includes an ammeter, or
if the current is not measured, connect the load directly to the
evaluation board with the positive (+) load connection to the
VOUT terminal and the negative (−) load connection to the GND
terminal just above the VOUT terminal. If an ammeter is used,
connect it in series with the load; connect the positive (+)
INPUT AND OUTPUT VOLTMETERS
Measure the input and output voltages with voltmeters. Connect
the voltmeter measuring the input voltage with the positive lead
(+) connected to TP1 and the negative lead (−) connected to
TP2. Connect the voltmeter measuring the output voltage with
the positive lead (+) connected to TP4 and the negative lead (−)
connected to TP3. Make sure to connect the voltmeters to the
appropriate evaluation board terminals and not to the load or
power source themselves. If the voltmeters are not connected
directly to the evaluation board at these Kelvin connection test
points (TP1 to TP4), the measured voltages will be incorrect
due to the voltage drop across the leads connecting the
evaluation board to both the source and load.
TURNING ON THE EVALUATION BOARD
After the power source and load are connected to the ADP1864
evaluation board, the board can be powered for operation. Slowly
increase the input power source voltage until the input voltage
exceeds the minimum input operating voltage of 9 V. If the load
is not already enabled, enable the load and check that it is drawing
the proper current and that the output voltage maintains voltage
regulation.
VOLTAGE SOURCE
VIN
IIN
SWITCH NODE
WAVEFORM
ELECTRONIC LOAD
VOLTMETER
VOUT
IOUT
INDUCTOR
CURRENT
WAVEFORM
CURRENT
PROBE
OUTPUT VOLTAGE
WAVEFORM
Figure 2. Measurement Setup
Rev. C | Page 3 of 16
05612-018
OSCILLOSCOPE
EVAL-ADP1864
MEASURING THE PERFORMANCE OF THE EVALUATION BOARD
MEASURING OUTPUT VOLTAGE RIPPLE
MEASURING THE INDUCTOR CURRENT
To observe the output voltage ripple, place an oscilloscope
across the output capacitor (COUT) with the probe ground lead
at the negative (−) capacitor terminal and the probe tip at the
positive (+) capacitor terminal. Set the oscilloscope to ac-coupled,
100 mV/division, and 2 μs/division time base. For a more accurate
measurement, the test leads should be as short as possible, as
shown in Figure 3. The output ripple voltage increases as the
input voltage is increased because the duty cycle is decreased.
The inductor current can be measured by removing one end of
the inductor from its pad and connecting a wire with adequate
current handling capabilities from the pad to inductor lead.
Then, a current probe can be used to measure the current
through the inductor, as shown in Figure 2.
MEASURING THE SWITCHING WAVEFORM
To observe the switching waveform with an oscilloscope, place
the oscilloscope probe tip to TP6 with the probe ground at test
point near the anode of the diode, which is on the GND plane.
Set the scope to dc coupling, 2 V/division, and 2 μs/division
time base. The switching waveform should alternate between
the negative forward voltage drop of the diode and approximately the input voltage with resonances near the switching
transitions.
MEASURING THE GATE-TO-SOURCE WAVEFORM
Using the voltages from the voltmeters and current readings
from the source and load, calculate efficiency from the
following equation:
n=
VOUT × I OUT
V IN × I IN
Sweep the load across the full load range to obtain the efficiency
and load regulation plot.
The efficiency results should correspond to the ADP1864 Buck
Design Software.
MEASURING LINE REGULATION
Vary the input voltage and examine the change in the output
voltage reading from the voltmeter.
MONITORING SHORT-CIRCUIT BEHAVIOR
Place a current probe on the load cable that connects the output
to the positive input of the electronic load. Monitor the output
voltage with a similar technique used to measure the output
voltage ripple; however, dc couple the scope with a 5 V/div
setting. Many electronic loads have short-circuit capability.
Enable this function on the load and ensure that the circuit
current limits at the correct current.
05612-017
To observe the gate-to-source waveform, place an oscilloscope
probe at TP7 with the ground lead at the test point nearest to
the anode of the diode, which is on the GND plane. Place
another oscilloscope probe at the source of the MOSFET with
the ground lead at the test point nearest the anode of the diode.
Use the math functions of the oscilloscope to observe the gateto-source waveform. Do not place a probe across gate-to-source
terminals of the MOSFET unless a differential probe is being
used. For a more accurate measurement, the test leads should be
as short as possible, as shown in Figure 3.
MEASURING EFFICIENCY AND LOAD REGULATION
Figure 3. Measuring Technique for Output Voltage Ripple
Rev. C | Page 4 of 16
EVAL-ADP1864
TYPICAL PERFORMANCE CHARACTERISTICS
C3
DC1M
5.00V/div
–5.00V ofst
Timebase –1.32µs Trigger
WStream
500ns Auto
12.5ks
2.5GSPS Edge
C4 DC
3.05V
Positive
C3 BWL AC1M
50.0mV/div
0.0mV ofst
Figure 4. Switch Node Ringing at 3 A Load; VIN = 9 V
Timebase –4.76µs Trigger
WStream 2.00ns Auto
2.5GSPS Edge
50.0ks
C4 DC
4.55V
Positive
05612-005
C4
05612-002
C4
Figure 7. VOUT Ripple at 3 A Load; VIN = 12 V
C4
Timebase –1.19µs Trigger
WStream
500ns Auto
12.5ks
2.5GSPS Edge
C4 DC
4.55V
Positive
C4
DC1M
5.00V/div
–5.00V ofst
Figure 5. Switch Node Ringing at 3 A Load; VIN = 12 V
Timebase –1.19µs Trigger
500ns Stop
WStream
2.5GSPS Edge
12.5ks
C4 DC
4.55V
Positive
05612-006
DC1M
5.00V/div
–5.00V ofst
C4 DC
7.00V
Positive
05612-007
C4
05612-003
C4
Figure 8. Gate Waveform 3 A; VIN = 9 V
C3
C3 BWL AC1M
50.0mV/div
0.0mV ofst
Timebase 0.00µs Trigger
WStream 2.00ns Single
50.0ks
2.5GSPS Edge
C1 DC
–168mV
Positive
05612-004
C4
C4
DC1M
5.00V/div
–5.00V ofst
Figure 6. VOUT Ripple at 3 A Load; VIN = 9 V
Timebase –2.38µs Trigger
WStream 1.00ns Stop
2.5GSPS Edge
25.0ks
Figure 9. Gate Waveform 3 A; VIN = 12 V
Rev. C | Page 5 of 16
EVAL-ADP1864
IOUT
VOUT
IOUT
C3
C2
VOUT
DC C3 BWL AC1M
1.00A/div
100mV/div
0mA offset
0.0mV ofst
Timebase –476µs Trigger
200µs Auto
WStream
1.00MS 500MSPS Edge
C2 DC
2.21A
Positive
C2
DC C3
DC1M
5.00A/div
5.00V/div
–5.00A ofst
–10.00V ofst
Timebase –119µs Trigger
WStream
50.0µs Stop
1.25MS 2.5GSPS Edge
C2 DC
5.35A
Positive
05612-011
C2
05612-008
C3
Figure 13. Short Circuit; VIN = 12 V
Figure 10. Load Transient; 1.5 A to 3 A at 250 mA/μs, VIN = 9 V
IOUT
IOUT
C2
VOUT
COMP/EN
C3
C4
VOUT
C3
C2
DC C3 BWL AC1M
1.00A/div
100mV/div
0mA offset
0.0mV ofst
Timebase –476µs Trigger
200µs Auto
WStream
1.00MS 500MSPS Edge
C2 DC
2.21A
Positive
C3
DC1M C4
DC1M
1.00V/div
1.00V/div
–2.030V ofst
0mV offset
Figure 11. Load Transient; 1.5 A to 3 A at 250 mA/μs, VIN = 12 V
Timebase –119µs Trigger C2 DC
WStream
50.0µs Stop
1.15V
1.25MS 2.5GSPS Edge
Negative
05612-012
DC
2.00A/div
2.860A ofst
05612-009
C2
Figure 14. Disable; VIN = 9 V
IOUT
C2
IOUT
COMP/EN
C4
C2
VOUT
VOUT
C3
C3
C2
DC C3
DC1M
5.00A/div
5.00V/div
–5.00A ofst
–10.00V ofst
Timebase –119µs Trigger
WStream
50.0µs Stop
1.25MS 2.5GSPS Edge
C2 DC
5.35A
Positive
C3
Figure 12. Short Circuit; VIN = 9 V
DC1M C4
DC1M
1.00V/div
1.00V/div
–2.030V ofst
0mV offset
Timebase –119µs Trigger C3 DC
WStream
50.0µs Stop
1.15V
1.25MS 2.5GSPS Edge
Negative
Figure 15. Disable; VIN = 12 V
Rev. C | Page 6 of 16
05612-013
DC
2.00A/div
2.860A ofst
05612-010
C2
EVAL-ADP1864
1.0
0.9
3.289
VIN = 9V
0.8
OUTPUT VOLTAGE (V)
3.284
VIN = 12V
0.6
0.5
0.4
0.3
3.279
VIN = 9V
3.274
VIN = 12V
3.269
0.2
0
0.01
0.1
1
LOAD CURRENT (A)
10
3.264
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
Figure 17. Load Regulation
Figure 16. Efficiency vs. Load Current
Rev. C | Page 7 of 16
3.0
3.5
05612-015
0.1
05612-014
EFFICIENCY(%)
0.7
EVAL-ADP1864
05612-019
EXCEL DESIGN TOOL INTERFACE
Figure 18. Excel Design Tool Interface
ENTER PERFORMANCE SPECIFICATIONS
In this section, the user can provide the specifications on how
the power supply being designed needs to perform. The voltage
range for the first two pull-down menus (Vinmin and Vinmax)
is 3.15 V to 14 V. In the third pull-down menu, the user provides
the required regulated output voltage (Vout), which needs to be
less than Vinmin and Vinmax, because this tool is to be used
with the buck topology. The next pull-down menu is the required
output current (Ioutmax). It is wise to design for the peak current
the regulator needs to provide, even if the peak is required for
only a short period of time. Without taking this into consideration, it is possible to hit the current limit when peak current is
needed. The information provided in the ambient temperature
(Tmax ambient) pull-down menu allows the estimated temperature to be computed for each component. This is a required
piece of information to ensure that the parts selected are thermally
capable of handling the rise in temperature associated with
internal losses of the parts. The switching frequency is internally
set in the ADP1864 to 580 kHz. There is a tolerance on this
specification, and the minimum and maximum limits can be
selected through the pull-down menu (Fsw). When the
switching frequency is at a minimum, the current in the
inductor rises to a slightly higher amplitude than in the nominal
switching frequency case. Consequently, the voltage across the
sense resistor will also be higher, which needs to be accounted
for when the tool calculates the current limit trip point. A
robust design should always consider this minimum switching
frequency. Additionally, the performance of the system can be
viewed when selecting the maximum switching frequency from
the pull-down menu.
The inductor ripple selection (IripplemaxL) affects several
parameters. As a general guideline, it is recommended to set
this value between 30% to 50% of the output load. A small
inductor allows energy to be transferred from the input to the
output more quickly during a load step, resulting in a smaller
output voltage excursion during the load step. However, a small
inductor requires a higher current rating of the inductor itself,
that is, the ripple current is inversely proportional to the size of
the inductor. Higher ripple current also translates to higher
output voltage ripple for a fixed capacitance value. Selecting the
maximum output voltage ripple from the next pull-down menu
(Vripple ppk) determines the amount and type (MLCC, aluminum electrolytic, for example) of output capacitance needed and
correspondingly how the compensation components are sized.
Rev. C | Page 8 of 16
EVAL-ADP1864
As a general guideline, it is recommended to set this value
around 5%. In the next pull-down menu (Ioutstep), the user
can select the estimate of the largest step in load the regulator
will demand. This, in conjunction with the allowable voltage
excursion on load transient (in the Vout step error pull-down
menu), delegates how much output capacitance is required. If
the Ioutstep specification is not known, entering a 50% load
step provides an adequate design for most applications at the
power level the ADP1864 is designed to be used.
SELECT COMPONENT VALUES AND SIZES
When starting a new design, it is recommended to reset each of
the pull-down menus to Auto, which is at the top of the list for
each option. With these settings, the tool automatically calculates
the most efficient design and provides that solution. If the user
would like to explore how other components affect various
parameters of the system, all the parts of the regulator except
the compensation components can be changed through the use
of the pull-down menus in this section. Note that the tool provides
a bill of materials that maintains all specifications entered in the
Enter Performance Specifications section of the tool when a
component is changed. Accordingly, other component values
can change as well. The feedback resistor selector at the bottom
of this section finds the right combination of resistors to
provide the feedback voltage with the 0.8 V.
POWER DISSIPATION AND TEMPERATURE
The Power Dissipation and Temperature section of the tool
provides the user with the power dissipation of each part at the
full rated current at both the maximum and minimum input
voltages. It also provides the user with the estimated temperature
of the ADP1864, the MOSFET, the diode, and the inductor. These
calculations are done taking into account the temperature rise
due to dissipation as well as the ambient temperature.
EFFICIENCY
From the power dissipation information calculated in the
Power Dissipation and Temperature section of the tool, the
efficiency across the full load range is plotted for both
maximum and minimum input voltages.
APPLICATION SCHEMATIC
The Application Schematic section provides a schematic of the
ADP1864 evaluation board. The reference designators on the
evaluation board match this schematic.
BOM SUMMARY
The BOM Summary provides the user with the final parts
list necessary to meet all the requirements entered into the
performance specifications section. Vendors, part numbers,
individual and total area, along with a value for each component,
are provided. If no part number is provided, a vital specification
is given instead. This specification can be used to find a part to
populate on the board. From this BOM, the user can modify the
fully populated configuration or populate the bare board
configuration to validate design changes.
Rev. C | Page 9 of 16
EVAL-ADP1864
MODIFYING THE EVALUATION BOARD
The ADP1864-EVALZ evaluation board is complete and tested
for operation. Due to the versatility of the ADP1864 step-down
dc-to-dc controller, the ADP1864 evaluation board can be
modified for a variety of external components. Some of the
most common modifications are described in this section.
CHANGING THE MOSFET
The ADP1864-EVALZ evaluation board is supplied with a
Siliconix Si5435 power MOSFET. The layout can accommodate
MOSFETs placed in parallel to accommodate higher current
levels. Additionally, 8-lead SOIC, thermally enhanced 8-lead
SOIC, 6-lead TSOP, 1206-8, and SOT-23 packages all have
footprints available on the ADP1864 evaluation board. On
resistances, gate charges and capacitances, gate-to-source
thresholds, and maximum drain to source voltage ratings
should all be considered before changing the MOSFET.
CHANGING THE SENSE RESISTOR
If an increase in current capability is desired, it may be necessary
to change the current limit via the sense resistor. As supplied,
two 33 mΩ resistors in parallel are used to sense current. For
duty cycles <40%, the current limit voltage is 125 mV typically.
For duty cycles >40%, use the slope factor (SF) vs. duty cycle
plot in the ADP1864 data sheet to determine the actual current
sense limit.
for all these changes when the new inductance value is selected
from the L1 pull-down menu. It then provides new suggestions
for component values. The Applications Information section of
ADP1864 data sheet also provides information concerning the
implications of changing the output inductor. If the duty cycle is
to exceed 40%, keep the ripple current to 30% to 50% of the
output current so that the slope compensation remains
effective. See the ADP1864 data sheet for more details.
CHANGING THE OUTPUT CAPACITORS
The ADP1864-EVALZ evaluation board is supplied with a 100 μF
ceramic capacitor on the output. If the capacitance is insufficient
to meet load transient requirements, a D-case tantalum capacitor
footprint and an 8 mm electrolytic capacitor footprint are
available to provide the capability to greatly increase the output
capacitance. Any change in output capacitance also requires a
change in compensation component values. To compensate for
a change in output capacitor, use the following equations:
RC =
C C1 =
C C0 =
Note that across the full temperature range and input voltage range
of the ADP1864, the current limit voltage can be as low as 80 mV.
C C0 =
CHANGING THE DIODE
The ADP1864-EVALZ evaluation board is supplied with a
Diodes, Inc. PDS1040L Schottky diode. The board can accommodate SMC, DPAK (TO-252), and other popular packages.
The two primary factors to consider when changing the diode
are the current handling capabilities as well as the maximum
reverse dc blocking voltage. Because of switch node voltage
excursions, it is recommended to select a diode with at least three
times the reverse dc blocking voltage as the maximum input
voltage for the application when no snubber circuit is used.
CHANGING THE OUTPUT INDUCTOR
The ADP1864-EVALZ evaluation board is populated with a
Coilcraft DO3316P-332ML 3.3 μH inductor with a saturation
current of 6.4 A. To operate at currents higher than this, the
inductor needs to be modified to accommodate at least the higher
current plus half the inductor ripple current. If the current
demand is less, it could be advantageous to select a physically
smaller and lower saturation current inductor for cost considerations. Changing the inductance value can affect the stress on
the transistor and diode, the output voltage ripple, and the load
transient response. The ADP1864 Buck Design Software accounts
2π × f UN × C OUT × ( ESR + R LOAD ) 2 × V OUT × R CL × G C
G M × R LOAD 2 × V REF
3
2π × R C × f UN
2π × f UN
G M × R LOAD × ESR × V REF
or
× ( ESR + R LOAD ) × R CL × G C × V OUT
3
, whichever is larger.
2π × R C × f SW
where:
fUN is the desired unity gain frequency in hertz (usually 40 kHz).
COUT is output capacitance in farads.
ESR is the effective series resistance of COUT in ohms.
RLOAD is VOUT (volts)/maximum load current (amps).
RCL is the parallel resistance of the current sense resistors in ohms.
GC is the nominal gain of the current sense amplifier (12).
GM is the nominal gain of the error amplifier (2.4 × 10−4 mhos).
VREF is the nominal error amplifier reference voltage (0.8 V).
fSW is the nominal switching frequency of the ADP1864
(580 kHz).
If multiple output capacitors are used and of the same type and
value, ESR is defined as the parallel effective series resistance of
all the capacitors. If multiple output capacitors are used that are
not of the same type and value, the analysis to calculate optimal
compensation components is considerably more complicated
and beyond the scope of this document.
It is recommended to always refer to the manufacturer’s data for
capacitance derating over applied voltage and temperature.
Rev. C | Page 10 of 16
EVAL-ADP1864
CHANGING THE OUTPUT VOLTAGE
The ADP1864-EVALZ evaluation board output regulation
voltage can be changed by altering the voltage divider consisting
of RF2 and RF1. The output regulation voltage is determined by
the following equation:
Modifying the output voltage changes the inductor ripple
current and subsequently the output voltage ripple, transient
response, and stress on the PFET. The design tool considers this
and, if necessary, provides new component values.
⎛ R + RF1 ⎞
⎟⎟
VOUT = 0.8 × ⎜⎜ F 2
RF1
⎠
⎝
Rev. C | Page 11 of 16
EVAL-ADP1864
SCHEMATIC
RIN1
LS
VIN
TP1
CIN1
C1
CIN4
CIN2
TP2
EN
ADP1864
R1
1
RC
COMP PGATE 6
2
GND
VIN 5
3
CF2
RF2
Q1-2
Q1-3
Q1-4
TP6
RCL2
RCL3
RCL4
D1
CS 4
FB
Q1-5
TP5
RCL1
RF1
L2
TP7
Q1-1
CC0
CS
RS
L1
VOUT
COUT2
TP4
COUT1
TP3
05612-001
CC1
U1
Figure 19. ADP1864-EVALZ Evaluation Board Schematic
Rev. C | Page 12 of 16
EVAL-ADP1864
05612-020
1900mm
ASSEMBLY DRAWING
1900mm
05612-021
Figure 20. ADP1864-EVALZ Evaluation Board Assembly Drawing, Front
Figure 21. ADP1864-EVALZ Evaluation Board Assembly Drawing, Back
Rev. C | Page 13 of 16
EVAL-ADP1864
ORDERING INFORMATION
BILL OF MATERIALS
Table 1. ADP1864-EVALZ
Qty.
1
Package
6-lead TSOT
Area
(mm2)
9
Manufacturer and
Part Number
Analog Devices
ADP1864AUJZ-R7
Designator
U1
Value
Comments
CC0
33 pF
1
0603
1.3
X7R or COG ceramic, 10% tolerance
CC1
0.82 nF
1
0603
1.3
X7R or COG ceramic, 10% tolerance
CIN1
10 μF
1
1210
8
TDK C3225X7R1C106M
COUT1
100 μF
1
1210
8.0
TDK C3225X5R0J107M
RC
27.4 kΩ
1
0603
1.3
RCL1, RCL2
0.033 Ω
2
0805
6.4
RF1
80.6 kΩ
1
0603
1.3
RF2
249 kΩ
1
0603
1.3
L1
3.3 μH, 15 mΩ
1
Drum
124
LS
Short
1
None
0
D1
10 A, 40 V
1
DI-5
27
J1
15-pin header
1
Header
96.8
Samtec HTSW-115-07-T-S
Q1-1
0.080 Ω
1
1206-8
5
Siliconix Si5435BDC
1% tolerance
Susumu RL1220T-R033-J
1% tolerance
1% tolerance
Coilcraft DO3316P-332ML
Shorted
Diodes, Inc. PDS1040L
Not populated
C1, CIN2, CIN4, CF2,
COUT2, CS, R1, RIN1,
RCL3, RCL4, RS, L2,
Q1-2, Q1-3, Q1-4,
Q1-5
Table 2. ADP1864-BL-EVALZ
Designator
U1
Value
Qty.
1
Package
6-lead TSOT
Area
(mm2)
9
J1
15-pin header
1
Header
96.8
ORDERING GUIDE
Model
ADP1864-EVALZ1
ADP1864-BL-EVALZ1
1
Manufacturer and
Part Number
Analog Devices
ADP1864AUJZ-R7
Samtec HTSW-115-07-T-S
ESD CAUTION
Description
Evaluation Board
Blank Evaluation Board
Z = RoHS Compliant Part.
Rev. C | Page 14 of 16
Comments
EVAL-ADP1864
NOTES
Rev. C | Page 15 of 16
EVAL-ADP1864
NOTES
©2006–2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
EB05612-0-7/09(C)
Rev. C | Page 16 of 16
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