an1925

Application Note 1925
ISL8271MEVAL1Z Evaluation Board User Guide
The ISL8271M is a 33A step-down DC/DC power supply
module with integrated digital PWM controller, synchronous
power switches, an inductor and passives. Only bulk input and
output capacitors are needed to finish the design. The 33A of
continuous output current can be delivered without a need of
airflow or a heatsink. The ISL8271M uses ChargeMode™
control architecture, which responds to a transient load within
a single switching cycle.
The ISL8271MEVAL1Z evaluation board is a 3inx4.5in 4-layer
FR4 board with 2 oz. in all layers. This evaluation board comes
with a placeholder for pin-strap resistors to adjust output
voltage, switching frequency, input undervoltage (UVLO)
protection threshold, and device PMBus™ address. More
configuration such as soft-start, and fault limits can be easily
programmed or changed via PMBus compliant serial bus
interface.
ZLUSBEVAL3Z (USB to PMBus adapter) is provided with this
evaluation kit, which connects the evaluation board to a PC to
activate the PMBus communication interface. The PMBus
command set is accessed by using the PowerNavigator™
evaluation software from a PC running Microsoft Windows.
References
“ISL8271M” datasheet
Ordering Information
PART NUMBER
ISL8271MEVAL1Z
DESCRIPTION
ISL8271M Kit (EVB, ZLUSBEVAL3Z Adapter,
USB Cable)
Key Features
• VIN range of 4.5V to 14V, VOUT adjustable from 0.6V to 5V
• Programmable VOUT, margining, UV/OV, IOUT limit,
soft-start/stop, sequencing, and external synchronization
• Monitor: VIN, VOUT, IOUT, temperature, duty cycle, switching
frequency and faults
• ChargeMode™ control tunable with PMBus
• Mechanical switch for enable and power-good LED indicator
Recommended Equipment
• DC power supply with minimum 15V/25A sourcing capacity
• Electronic load capable of sinking current up to 33A
• Digital multimeters (DMMs)
• Oscilloscope with higher than 100MHz bandwidth
Functional Description
The ISL8271MEVAL1Z provides all circuitry required to
evaluate the features of the ISL8271M. A majority of the
features of the ISL8271M, such as compensation-free
ChargeMode™ control, soft-start delay and ramp times, supply
sequencing, and voltage margining are available on this
evaluation board. For sequencing evaluation, the board can be
connected to any Intersil digital module evaluation board that
supports the Digital-DC™ (DDC) bus.
Figure 1 shows a board image of the ISL8271MEVAL1Z
evaluation board.
INTERCONNECTS DDC AND
SYNC BETWEEN BOARDS
PGOOD LED
INTERCONNECTS DDC AND
SYNC BETWEEN BOARDS
ENABLE SWITCH
CONNECT TO ZLUSBEVAL3Z
DONGLE. FOR MULTIPLE
BOARD EVALUATION,
CON-NECT TO PMBUS DONGLE
OUT CONNECTION OF OTHER
BOARD
TO DAISY CHAIN PMBus
CONNECTION
PLACEHOLDER FOR SMA
CONNECTOR TO MONITOR
VOUT RIPPLE
FIGURE 1. ISL8271MEVAL1Z EVALUATION BOARD IMAGE
August 15, 2014
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1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2014. All Rights Reserved
Intersil (and design), PowerNavigator, ChargeMode and Digital-DC are trademarks owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
Application Note 1925
Operation
PMBus Operation
The ISL8271M utilizes the PMBus protocol. The PMBus
functionality can be controlled via ZLUSBEVAL3Z dongle from a
PC running the PowerNavigator™ evaluation software in a
Windows XP or Windows 7 operating systems.
Install the evaluation software from the following Intersil
website: www.intersil.com/powernavigator
For board operation, connect the included ZLUSBEVAL3Z dongle
to the 6-pin male connector labeled as “PMBus DONGLE IN”.
Connect the desired load and an appropriate power supply to the
input and connect the included USB cable to the PC running the
PowerNavigator™ evaluation software. Place the ENABLE
switches in “DISABLE” before turning on the power.
The evaluation software allows modification of all ISL8271M
PMBus parameters. The ISL8271M device on the board has been
pre-configured as described in this document, but the user may
modify the operating parameters through the evaluation
software or by loading a predefined set-up from a configuration
file. A sample “Configuration File” on page 5 is provided and can
be copied to a notepad editor to make desired changes.
The ENABLE switch can then be moved to “ENABLE” and the
ISL8271MEVAL1Z board can be tested. Alternately, the PMBus
ON_OFF_CONFIG and OPERATION commands may be used from
the PowerNavigator™ GUI.
Quick Start Guide
Pin-Strap Option
The ISL8271MEVAL1Z can be configured in pin-strap mode with
standard 1% 0603 resistors. PMBus interface is not required to
evaluate ISL8271M in pin-strap mode. Output voltage (VOUT),
switching frequency (FSW), input undervoltage protection (UVLO)
threshold and device PMBus address can be changed by
populating recommended resistors at placeholders provided in
the evaluation board. By default, the evaluation board is
programmed to regulate at VOUT = 1.2V, FSW = 533kHz,
UVLO = 4.5V, and PMBus address = 28h. Follow these steps to
evaluate ISL8271M in pin-strap mode.
1. Set ENABLE switch to “DISABLE”.
2. Connect Load to VOUT lug connectors (J7 and J8).
3. Connect power supply to VIN connectors (J3 and J4). Make
sure power supply is not enabled when making connection.
4. Turn power supply on.
5. Set ENABLE switch to “ENABLE”.
6. Measure 1.2V VOUT at probe points (TP10 and TP11)
7. Observe switching frequency of 533kHz at probe point
labeled VSWH (TP1).
8. To change VOUT, disconnect board from the set up and
populated 1% standard 0603 resistor at R6 placeholder
location on bottom layer. Refer to the “Output Voltage
Resistor Settings” table in the ISL8271M datasheet for
recommended values. By default, VOUT_MAX is set to 110%
of VOUT set by the pin-strap resistor.
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2
9. To change switching frequency, disconnect board from the
setup and populated 1% standard 0603 resistor at R2
placeholder location on bottom layer. Refer to the “Switching
Frequency Resistor Settings” table in the ISL8271M
datasheet for recommended values.
10. To change UVLO, disconnect board from the setup and
populated 1% standard 0603 resistor at R7 placeholder
location on bottom layer. Refer to the “UVLO Resistor Settings”
table in the ISL8271M datasheet for recommended values.
PMBus Option
ISL8271MEVAL1Z can be evaluated for all features using the
provided ZLUSBEVAL3Z dongle and PowerNavigator™ evaluation
software. Follow these steps to evaluate ISL8271M with PMBus
option.
1.
2.
3.
4.
Install PowerNavigator™ software.
Set ENABLE switch to “DISABLE”.
Connect Load to VOUT lug connectors (J7 and J8).
Connect power supply to VIN connectors (J3 and J4). Make
sure power supply is not enabled when making connection.
5. Turn power supply on.
6. Connect ZLUSBEVAL3Z dongle (USB to PMBus™ adapter) to
ISL8271MEVAL1Z board to the 6-pin male connector labeled
as “PMBus DONGLE IN”.
7. Connect supplied USB cable from computer to USB to
ZLUSBEVAL3Z dongle.
8. Launch PowerNavigator™ software.
9. Set ENABLE switch to “ENABLE”.
10. Monitor and configure the ISL8271MEVAL1Z board using
PMBus commands in the evaluation software.
11. PowerNavigator™ tutorial videos are available at Intersil
website. www.intersil.com/powernavigator
12. For sequencing via Digital-DC Bus (DDC) or to evaluate
multiple Intersil digital power products using a single
ZLUSBEVAL3Z dongle, ISL8271M can be daisy chained with
other digital power evaluation boards. PMBus address can be
changed by placing a 1% standard 0603 resistor at the R5
placeholder location on the bottom layer. Refer to the “SMBus
Address Resistor Selection” table in the ISL8271M datasheet
for recommended values.
Thermal Considerations and
Current Derating
Board layout is very critical in order to make the module operate
safely and deliver maximum allowable power. To work in the high
temperature environments and carry large currents, the board
layout needs to be carefully designed to maximize thermal
performance. To achieve this, select enough trace width, copper
weight and the proper connectors.
The ISL8271MEVAL1Z evaluation board is designed for running
33A at room temperature without additional cooling systems
needed. However, if the output voltage is increased or the board
is operated at elevated temperatures, then the available current
is derated. Refer to the derated current curves in the ISL8271M
datasheet to determine the maximum output current the
evaluation board can supply. JA is measured by inserting
thermocouple inside the module to measure peak junction
temperature.
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August 15, 2014
SW1
GT11MCBE
2
MSTR_SYNC
R1
1
VR5
10K
XTEMP-
VIN
PG
R9
1K
V25
TP2
37 VDDC
TP3
C6
10uF
Q1
2N7002
UVLO
NC
SGND
TP6
VSEN+
6
VSEN+
VSEN-
7
VSEN-
1
VDDC
NC
3 2
38
SYCN
2
1
EN
SCL
SDA
SALRT
SA
16
2
3
PG
VDD
V25
2
1
2
3
4
5
6
NC
1
39
17
18
19
20
21
23
24
25
2
2
ENABLE
2
DISABLE
D1
R8
10K
6
4
DNP
R2
1
2
1
2
R5
1 OPEN
R6
OPEN
1
PG
1
SGND
15
J9
PGND
C7
1uF
+
+
R11
200
C14
470uF
2
34
C13
470uF
1
1
TP5
1
TP4
VR6
NC
+
C5
22uF
VSEN+
VIN
NC
1
C4
22uF
2
2
J4
1
11
2
C1
150uF
1
C2
150uF
2
+
VR5
35
VDRVIN
1
1
10
36
2
2
PGND
2
R3
2.2
2
PHASE
1
1
VIN
2
J3
DNP
VR6
1
2
C8
10uF
TP8
5
4
9
C15
1.0uF
2
VDRVOUT
2
3
1
VR5
TP7
8
1
C3
22uF
J7
TP10
PGND
VOUT
31
14
1
VOUT
1
100 uF
C11
2
1
1
100 uF
C10
2
2
100 uF
C9
2
1
KPA8CTP
TP9
VOUT
100 uF
C12
J8
1
PGND
KPA8CTP
40
TP11
30
U1
ISL8271MIRZ
VSWH
13
12
TP1
FIGURE 2. APPLICATION CIRCUIT
VSEN-
Application Note 1925
MSTR_SYNC
RSVD1
GND
DDC
RSVD2
RSVD3
PGND
XTEMP+
MGN
2
VSET
DDC
NC
2
3
1
1
J6
1
2
3
4
5
6
28
R7
OPEN
R4
4.7K
JP1
J5
1
VR5
29
1
2
3
4
5
6
27
SDA
SALRT
SCL
GND
Vi2c
MSTR_EN
SGND
1
2
3
4
5
6
2
J15
2
3
J1
1
MSTR_EN
SCL
SDA
SALRT
1
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ISL8271MEVAL1Z Board Schematic
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August 15, 2014
Application Note 1925
Bill of Materials
REFERENCE DESIGNATOR
QTY
MANUFACTURER
MANUFACTURER PART
DESCRIPTION
C7
1
MURATA
GRM188R71E105KA12D
CAP, SMD, 0603, 1µF, 25V, 10%, X7R, ROHS
C3-C5
3
MURATA
GRM32ER71E226KE15L
CAP, SMD, 1210, 22µF, 25V, 10%, X7R, ROHS
C15
1
PANASONIC
ECJ-0EB0J105K
CAP, SMD, 0402, 1µF, 6.3V, 10%, X5R, ROHS
C8
1
PANASONIC
ECJ-1VB1A106M
CAP, SMD, 0603, 10µF, 10V, 20%, X5R, ROHS
C6
1
TDK
C2012X5R1E106K
CAP, SMD, 0805, 10µF, 25V, 10%, X5R, ROHS
C9, C10, C11, C12
4
TDK
C3225X5R0J107M
CAP, SMD, 1210, 100µF, 6.3V, 20%, X5R,
ROHS
C1, C2
2
SANYO/PANASONIC
16TQC150MYF
CAP-POSCAP, SMD, 7.3x4.3, 150µF, 16V, 20%,
50mΩ, ROHS
C13, C14
2
SANYO/PANASONIC
6TPF470MAH
CAP TANT 470µF 6.3V 20%
TP8, TP10
2
KEYSTONE
5000
CONN-MINI TEST PT, VERTICAL, RED, ROHS
TP9, TP11
2
KEYSTONE
5001
CONN-MINI TEST PT, VERTICAL, BLK, ROHS
J3, J4
2
KEYSTONE
575-4
CONN-JACK, MINI BANANA, 0.175 PLUG,
NICKEL/BRASS, ROHS
J2, J6
2
SAMTEC
SSQ-103-02-T-D-RA
CONN-SOCKET STRIP, TH, 2X3, 2.54mm, TIN,
R/A, ROHS
J1, J5
2
SAMTEC
TSW-103-08-T-D-RA
CONN-HEADER, 2X3, BRKAWY, 2.54mm, TIN,
R/A, ROHS
D1
1
CHICAGO MINIATURE CMD17-21VGC/TR8
LED, SMD, 0805, GREEN, CLEAR, 10mcd, 2.1V,
20mA, 570nm, ROHS
U1
1
INTERSIL
ISL8271MIRZ
IC-25A DIGITAL DC/DC PMBUS MODULE, 26P,
QFN, ROHS
Q1
1
ON SEMICONDUCTOR 2N7002LT1G
TRANSISTOR-MOS, N-CHANNEL, SMD, SOT23,
60V, 115mA, ROHS
R4
1
YAGEO
RES, SMD, 0603, 4.7k, 1/10W, 1%, TF, ROHS
R2, R5, R6, R7
0
R3
1
PANASONIC
ERJ-3RQF2R2V
RES, SMD, 0603, 2.2Ω, 1/10W, 1%, TF, ROHS
R9
1
PANASONIC
ERJ-3EKF1001V
RES, SMD, 0603, 1k, 1/10W, 1%, TF, ROHS
R1, R8
2
KOA
RK73H1JT1002F
RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS
R11
1
PANASONIC
ERJ-8ENF2000V
RES, SMD, 1206, 200Ω, 1/4W,1%, TF, ROHS
SW1
1
ITT CANNON
GT11MCBE
SWITCH-TOGGLE, THRU-HOLE, SPDT, 5P, ROHS
J7, J8
2
BERG/FCI
KPA8CTP
HDWARE, MTG, CABLE TERMINAL, 6-14AWG,
LUG and SCREW, ROHS
J9
0
TE CONNECTIVITY
5-1814832-1
DO NOT POPULATE
JP1
0
DO NOT POPULATE
TP1-TP7
0
DO NOT POPULATE
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9C06031A4701FKHFT
RESISTOR, SMD, 0603, 0.1%, MF, DNPPLACE HOLDER
4
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Application Note 1925
Configuration File
Sample Configuration File for ISL8271M Module. Copy and paste (from RESTORE_FACTORY TO ### End User Store) to a notepad and
save it as Confile_file_name.txt. The # symbol is used for a comment line. Following settings are already loaded to ISL8271M module
as factory defaults.
RESTORE_FACTORY
STORE_USER_ALL
# VOUT Related
VOUT_COMMAND
VOUT_MAX
VOUT_MARGIN_HIGH
VOUT_MARGIN_LOW
VOUT_OV_FAULT_LIMIT
VOUT_OV_FAULT_RESPONSE
VOUT_OV_WARN_LIMIT
VOUT_UV_WARN_LIMIT
VOUT_UV_FAULT_LIMIT
VOUT_UV_FAULT_RESPONSE
POWER_GOOD_ON
VOUT_TRANSITION_RATE
VOUT_DROOP
VOUT_CAL_OFFSET
# IOUT Related
IOUT_CAL_GAIN
IOUT_CAL_OFFSET
IOUT_OC_FAULT_LIMIT
IOUT_UC_FAULT_LIMIT
MFR_IOUT_OC_FAULT_RESPONSE
MFR_IOUT_UC_FAULT_RESPONSE
ISENSE_CONFIG
# Other Faults
OT_FAULT_LIMIT
OT_FAULT_RESPONSE
OT_WARN_LIMIT
UT_WARN_LIMIT
UT_FAULT_LIMIT
UT_FAULT_RESPONSE
VIN_OV_FAULT_LIMIT
VIN_OV_FAULT_RESPONSE
VIN_OV_WARN_LIMIT
VIN_UV_WARN_LIMIT
VIN_UV_FAULT_LIMIT
VIN_UV_FAULT_RESPONSE
#Enable, Timing and Sequence Related
ON_OFF_CONFIG
TON_DELAY
TON_RISE
TOFF_DELAY
TOFF_FALL
POWER_GOOD_DELAY
FREQUENCY_SWITCH
SYNC_CONFIG
SEQUENCE
# Manufacturer Related
MFR_ID
MFR_MODEL
MFR_REVISION
MFR_LOCATION
MFR_DATE
MFR_SERIAL
USER_DATA_00
# Advance Settings
USER_CONFIG
DDC_CONFIG
DDC_GROUP
# Loop Compensation
ASCR_CONFIG
STORE_USER_ALL
### End User Store
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5
# reset device to the factory setting
# Clears user memory space
0x2666
0x2a3c
0x2851
0x247a
0x2c28
0x80
0x2a3c
0x228f
0x20a3
0x80
0x228f
0xba00
0x0000
0x0000
# 1.2 V
# 1.32 V
# 1.26 V
# 1.14 V
# 1.38 V
# Disable and no retry
# 1.32 V
# 1.08 V
# 1.02 V
# Disable and no retry
# 1.08 V
# 1 mV/us
# 0 mV/A
# 0 mV/A
0xb2ae
0x0000
0xe280
0xe57f
0x80
0x80
0x05
# 0.67 mV/A
#0A
# 40 A
# -40A
# Disable and no retry
# Disable and no retry
# 256ns Blanking time, Mid-Range
0xebe8
0x80
0xeb70
0xdc40
0xe530
0x80
0xd380
0x80
0xd327
0xca79
0xca40
0x80
# 125 °C
# Disable and no retry
# 110 °C
# -30 °C
# -45 °C
# Disable and no retry
# 14 V
# Disable and no retry
# 12.609 V
# 4.945 V
# 4.5 V
# Disable and no retry
0x17
0xca80
0xca80
0xca80
0xca80
0xba00
0x0215
0x00
0x0000
# Pin Enable, Immediate Off
# 5 ms
# 5 ms
# 5 ms
# 5 ms
# 1 ms
# Sequence Disabled
# Use Pin-strap for FSW setting
# 533 kHz
Intersil Corp
ISL8271MEVAL1Z
Rev-1
Milpitas, CA
3/14/2014
1234
Module
# Example Only
# Example Only
# Example Only
# Example Only
# Example Only
# Example Only
# Example Only
0x00
0x01
0x00000000
# Open Drain PG, XTEMP Disabled
# DDC rail ID = 1
# All Broadcast disabled
0x15a0100
# Store all above settings to NVRAM
# ASCR gain = 256, Residual = 90
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Application Note 1925
Measured Data
The following data was acquired using a ISL8271MEVAL1Z evaluation board.
100
95
5V
(700kHz)
95
2.5V
3.3V
1.8V
EFFICIENCY (%)
EFFICIENCY (%)
2.5V
85
80
1V
75
1.2V
0.8V
89
85
65
79
3
5
7
77
300
9 11 13 15 17 19 21 23 25 27 29 31 33
1.2V
83
81
1
1.8V
87
70
1V
0.8V
400
IOUT (A)
700
800
900
94
3.3V
2.5V
3.3V
1.8V
92
90
EFFICIENCY (%)
EFFICIENCY (%)
600
FIGURE 4. EFFICIENCY vs SWITCHING FREQUENCY AT VIN = 12V
AND IOUT = 33A FOR VARIOUS OUTPUT VOLTAGES
95
85
1.2V
1V
80
0.8V
75
70
2.5V
90
1.8V
88
1.2V
86
1V
84
0.8V
82
65
60
500
SWITCHING FREQUENCY (kHz)
FIGURE 3. EFFICIENCY vs OUTPUT CURRENT AT VIN = 12V AND
FSW = 533kHz FOR VARIOUS OUTPUT VOLTAGES
100
3.3V
91
90
60
5V
93
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33
80
300
400
500
600
700
800
900
SWITCHING FREQUENCY (kHz)
IOUT (A)
FIGURE 5. EFFICIENCY vs OUTPUT CURRENT AT VIN = 5V AND
FSW = 533kHz FOR VARIOUS OUTPUT VOLTAGES
FIGURE 6. EFFICIENCY vs SWITCHING FREQUENCY AT VIN = 5V AND
IOUT = 33A FOR VARIOUS OUTPUT VOLTAGES
VOUT (50mV/DIV)
FSW = 700kHz
ASCR GAIN = 500
RESIDUAL = 70
IOUT (10A/DIV)
20µs /DIV
FIGURE 7. LOAD TRANSIENT RESPONSE AT VIN = 12V, VOUT = 2.5V
WITH HIGH BANDWIDTH ASCR PARAMETERS
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2: 76.4°C
1: 81.3°C
TA = +25°C
FIGURE 8. THERMAL IMAGE, 12VIN TO 1.2VOUT, IOUT = 33A,
TA = +25°C, FSW = 533kHz, NO AIR FLOW.
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Application Note 1925
ISL8271MEVAL1Z Board Layout
FIGURE 9. PCB - TOP SILK SCREEN
FIGURE 10. PCB - TOP LAYER
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Application Note 1925
ISL8271MEVAL1Z Board Layout
(Continued)
FIGURE 11. PCB - INNER LAYER - LAYER 2 (TOP VIEW)
FIGURE 12. PCB - INNER LAYER - LAYER 3 (TOP VIEW)
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AN1925.1
August 15, 2014
Application Note 1925
ISL8271MEVAL1Z Board Layout
(Continued)
FIGURE 13. PCB - BOTTOM LAYER (BOTTOM VIEW)
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is
cautioned to verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
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