Renesas ISL8277M User manual

Rev 0.00 July 2017
User’s Manual
ISL8277MEVAL1Z
User’s Manual: Evaluation Board
Industrial Analog and Power

UG115 Rev.0.00 Page 2 of 16
Jul 28, 2017
UG115
Rev.0.00
Jul 28, 2017
ISL8277MEVAL1Z
Evalulation Board
USER’S MANUAL
1. Overview
The ISL8277M is a 25A step-down DC/DC power supply module with an integrated digital PWM controller,
synchronous power switches, an inductor, and passives. Only bulk input and output capacitors are needed to finish the
design. The 25A of continuous output current can be delivered without the need for airflow or a heatsink. The
ISL8277M uses ChargeMode™ control architecture, which responds to a transient load within a single switching
cycle.
The ISL8277MEVAL1Z evaluation board is a 3inx4.5in 4-layer FR4 board with 2oz. copper in all layers. This
evaluation board comes with a placeholder for pin-strap resistors to adjust output voltage, switching frequency, input
Undervoltage Lockout (UVLO) protection threshold, and device PMBus address. More configuration such as soft-start
and fault limits can be easily programmed or changed via a PMBus compliant serial bus interface.
The ZLUSBEVAL3Z (USB to PMBus adapter) is provided with this evaluation board, 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.
1.1 Key Features
•V
IN 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
1.2 Specifications
This board has been configured and optimized for the following operating conditions:
•V
IN = 5V to 12V
•V
OUT = 1.2V
•I
MAX = 25A
•f
SW = 533kHz
• Peak efficiency: >91% at 50% load
• ASCR gain = 250, ASCR residual = 90
• On/off delay = 5ms, On/off ramp time = 5ms
1.3 Ordering Information
1.4 Related Literature
• For a full list of related documents, visit our website
•ISL8277M product page
Part Number Description
ISL8277MEVAL1Z ISL8277M evaluation board (also included: ZLUSBEVAL3Z adapter, USB cable)

UG115 Rev.0.00 Page 3 of 16
Jul 28, 2017
ISL8277MEVAL1Z 1. Overview
1.5 Recommended Equipment
• DC power supply with minimum 15V/20A sourcing capacity
• Electronic load capable of sinking current up to 25A
• Digital multimeters (DMMs)
• Oscilloscope with higher than 100MHz bandwidth
Figure 1. Block Diagram
ISL8277M
VOUT
VIN
VDD
VOUT
VSEN+
VSEN-
VIN
PMBUS
INTERFACE
VDRVIN
VDRVOUT
CIN COUT
10µF
SALRT
SDA
SCL
SGND PGND
10µF
EN
ENABLE
VCC
VR55 10µF

UG115 Rev.0.00 Page 4 of 16
Jul 28, 2017
ISL8277MEVAL1Z 2. Functional Description
2. Functional Description
The ISL8277MEVAL1Z provides all circuitry required to evaluate the features of the ISL8277M. A majority of the
features of the ISL8277M, 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 2 on page 7 shows an image of the ISL8277MEVAL1Z evaluation board.
2.1 Operating Range
By default, the ISL8277MEVAL1Z is configured to operate at VOUT = 1.2V, fSW = 533kHz. VIN ranges are from
4.5V to 12V. The board can also support a wider operating range to meet the requirements of specific applications.
The VOUT can be adjusted from 0.6V to 5V. Load current range is from 0A to 25A. Note that, for continuous
operation at 25A, airflow across the board may be needed. The fSW and output voltage can also be tuned. However,
to ensure sufficient stability margins, switching frequency and output capacitors can only be selected using the
“ISL8277M Design Guide Matrix and Output Voltage Response” table in the ISL8277M datasheet.
If input voltage is less than 5.3V, tie the VCC test point directly to VIN or to a separate 5V power supply for normal
operation and best efficiency.
The ISL8277MEVAL1Z is capable of handling a 0A to 25A output current transient, in which the slew rate is less
than 2A/µs, such as electronic load. If the slew rate exceeds the 2A/us, then it may be necessary to increase the
output capacitance or change VOUT_OV_FAULT_LIMIT and VOUT_UV_FAULT_LIMIT values for proper
operation (refer to “PMBus Option” on page 5).
If external synchronization is used, connect the SYNC test point to the external clock. Note that the external clock
signal should be active before the module is enabled.
2.2 PMBus Operation
The ISL8277M uses the PMBus protocol. The PMBus functionality can be controlled through the ZLUSBEVAL3Z
dongle from a PC running the PowerNavigator evaluation software on Windows XP or Windows 7 operating
systems.
Install the evaluation software from the 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. Set the ENABLE switch to “DISABLE”
before turning on the power.
The evaluation software allows modification of all ISL8277M PMBus parameters. The ISL8277M device on the
board has been preconfigured as described in this document, but the user can 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 13 is provided and can be copied to a text editor to make desired changes.
The ENABLE switch can then be moved to “ENABLE” and the ISL8277MEVAL1Z board can be tested.
Alternately, the PMBus ON_OFF_CONFIG and OPERATION commands can be used from the PowerNavigator
GUI.

UG115 Rev.0.00 Page 5 of 16
Jul 28, 2017
ISL8277MEVAL1Z 2. Functional Description
2.3 Quick Start Guide
2.3.1 Pin-Strap Option
ISL8277MEVAL1Z can be configured in Pin-Strap mode with standard 1% 0603 resistors. The PMBus
interface is not required to evaluate ISL8277M in Pin-Strap mode. Output voltage (VOUT), switching frequency
(fSW), input undervoltage protection (UVLO) threshold, and the device PMBus address can be changed by
populating the 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 ISL8277M in Pin-Strap mode.
(1) Set the ENABLE switch to “DISABLE”.
(2) Connect a load to the VOUT lug connectors (J8 and J9).
(3) Connect a power supply to the VIN connectors (J1 and J2). Make sure the power supply is not enabled
when making the connection.
(4) Turn the power supply on.
(5) Set the ENABLE switch to “ENABLE”.
(6) Measure 1.2V VOUT at probe points TP9 and TP13.
(7) Observe switching frequency of 533kHz at probe point labeled VSWH (TP8).
(8) To change the VOUT, disconnect the board from the setup and populate with a 1% standard 0603 resistor at
R6 placeholder location on bottom layer. Refer to the “Output Voltage Resistor Settings” table in the
ISL8277M datasheet for recommended values. By default, VOUT_MAX is set 110% of VOUT set by pin-
strap resistor.
(9) To change the switching frequency, disconnect the board from the set up and populate with a 1% standard
0603 resistor at R2 placeholder location on bottom layer. Refer to the “Switching Frequency Resistor
Settings” table in the ISL8277M datasheet for recommended values.
(10) To change the UVLO, disconnect the board from the set up and populate with a 1% standard 0603 resistor
at R7 placeholder location on bottom layer. Refer to the “UVLO Resistor Settings” table in the ISL8277M
datasheet for recommended values.
2.3.2 PMBus Option
ISL8277MEVAL1Z can be evaluated for all features using the provided ZLUSBEVAL3Z dongle and
PowerNavigator evaluation software. Follow these steps to evaluate ISL8277M with the PMBus option.
(1) Install the PowerNavigator software.
(2) Set the ENABLE switch to “DISABLE”.
(3) Connect a load to the VOUT lug connectors (J8 and J9).
(4) Connect a power supply to the VIN connectors (J1 and J2). Make sure the power supply is not enabled
when making the connection.
(5) Turn the power supply on.
(6) Connect the ZLUSBEVAL3Z dongle (USB to PMBus adapter) to ISL8277MEVAL1Z board to the 6-pin
male connector labeled as “PMBus DONGLE IN”.
(7) Connect the supplied USB cable from the computer through USB to the ZLUSBEVAL3Z dongle.
(8) Launch the PowerNavigator software.
(9) Set the ENABLE switch to “ENABLE”.
(10) Monitor and configure the ISL8277MEVAL1Z 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, ISL8277M can be daisy chained with other digital power evaluation
boards. The 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 ISL8277M
datasheet for recommended values.

UG115 Rev.0.00 Page 6 of 16
Jul 28, 2017
ISL8277MEVAL1Z 3. PCB Layout Guidelines
3. PCB Layout Guidelines
To achieve stable operation, low losses, and good thermal performance some layout considerations are necessary.
The key features of the ISL8277MEVAL1Z layout are:
• Establish separate SGND plane and PGND plane, then connect SGND to PGND plane in the middle layer. For
making connections between SGND/PGND on the top layer and other layers, use multiple vias for each pin to
connect to inner SGND/PGND layer. Do not connect SGND directly to PGND on a top layer. Connecting SGND
directly to PGND without establishing SGND plane will bypass the decoupling capacitor at internal reference
supplies, making controller susceptible to noise.
• Place enough ceramic capacitors between VIN and PGND, VOUT and PGND, and bypass capacitors between VDD
and the ground plane, as close to the module as possible to minimize high frequency noise.
• Use large copper areas for power path (VIN, PGND, and VOUT) to minimize conduction loss and thermal stress.
Also, use multiple vias to connect the power planes in different layers. Extra ceramic capacitors at VIN and VOUT
can be placed on the bottom layer under VIN and VOUT pads when multiple vias are used for connecting copper
pads on top and bottom layers.
• Connect differential remote sensing traces to the regulation point to achieve a tight output voltage regulation. Route a
trace from VSEN+ and VSEN- to the point-of-load where the tight output voltage is desired. Avoid routing any
sensitive signal traces, such as the VSENSE signal near VSWH pads.
• For noise sensitive applications, it is recommended to connect VSWH pads only on the top layer; however, thermal
performance will be sacrificed. External airflow might be required to keep module heat at desired level. For
applications where switching noise is less critical, excellent thermal performance can be achieved in this power
module by increasing the copper mass attached to the VSWH pad. To increase copper mass on the VSWH node,
create copper islands in the middle and bottom layers under the VSWH pad and connect them to the top layer with
multiple vias. Make sure to shield those copper islands with a PGND layer to avoid any interference to noise sensitive
signals.
3.1 Thermal Considerations and Current Derating
Board layout is very critical to make the module operate safely and deliver maximum allowable power. To work in
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.
This evaluation board is designed for running 25A 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 ISL8277M 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.

UG115 Rev.0.00 Page 7 of 16
Jul 28, 2017
ISL8277MEVAL1Z 3. PCB Layout Guidelines
Figure 2. ISL8277MEVAL1Z Evaluation Board (Top Side)
Figure 3. ISL8277MEVAL1Z Evaluation Board (Bottom Side)
INTERCONNECTS
BETWEEN BOARDS
CONNECT TO ZLUSBEVAL3Z
DONGLE. FOR MULTIPLE
OUT CONNECTION OF OTHER
BOARD
PGOOD LED ENABLE SWITCH INTERCONNECTS DDC AND
SYNC BETWEEN BOARDS
TO DAISY CHAIN PMBus
CONNECTION
PLACEHOLDER FOR SMA
CONNECTOR TO MONITOR
VOUT RIPPLE
DDC AND SYNC
BOARD EVALUATION,
CONNECT TO PMBUS DONGLE

UG115 Rev.0.00 Page 8 of 16 Jul 28, 2017 ISL8277MEVAL1Z 3. PCB Layout Guidelines
3.2 ISL8277MEVAL1Z Board Schematic
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UG115 Rev.0.00 Page 9 of 16
Jul 28, 2017
ISL8277MEVAL1Z 3. PCB Layout Guidelines
3.3 Bill of Materials
Qty
Reference
Designator Description Manufacturer
Manufacturer
Part
1 PWB-PCB, ISL8277MEVAL1Z, REVC, ROHS SHENZHEN
MULTILAYER PCB
TECHNOLOGY CO.,
LTD
ISL8277MEVAL1ZREVCPCB
3 C4, C5, C6 CAP, SMD, 1210, 22µF, 25V, 10%, X7R, ROHS MURATA GRM32ER71E226KE15L
1 C17 CAP, SMD, 0402, 1µF, 6.3V, 10%, X5R, ROHS PANASONIC ECJ-0EB0J105K
2 C7, C8 CAP, SMD, 0603, 10µF, 16V, 10%, X5R, ROHS MURATA GRM188R61C106KAALD
1 C10 CAP, SMD, 0603, 4.7µF, 16V, 10%, X5R, ROHS VENKEL C0603X5R160-475KNE
0 C3 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS
1 C9 CAP, SMD, 0805, 10µF, 25V, 10%, X5R, ROHS TDK C2012X5R1E106K
4 C11, C12,
C13, C14
CAP, SMD, 1210, 100µF, 6.3V, 10%, X5R, ROHS AVX 12106D107KAT2A
2 C1, C2 CAP-POSCAP, SMD, 7.3x4.3, 150µF, 16V, 20%, 50mΩ,
ROHS
SANYO/PANASONIC 16TQC150MYF
2 C15, C16 CAP-POSCAP, SMD, 7.3x4.3, 470µF, 4V, 20%, 12mΩ,
ROHS
PANASONIC/SANYO 4TPE470MCL
7 TP1, TP4-TP9 CONN-MINI TEST PT, VERTICAL, RED, ROHS KEYSTONE 5000
2 TP2, TP13 CONN-MINI TEST PT, VERTICAL, BLK, ROHS KEYSTONE 5001
2 J1, J2 CONN-JACK, MINI BANANA, 0.175 PLUG,
NICKEL/BRASS, ROHS
KEYSTONE 575-4
1 J10 CONN-HEADER, 1x2, BRKAWY 1x36, 2.54mm, ROHS BERG/FCI 68000-236HLF
2 J5, J6 CONN-SOCKET STRIP, TH, 2x3, 2.54mm, TIN, R/A,
ROHS
SAMTEC SSQ-103-02-T-D-RA
2 J3, J4 CONN-HEADER, 2x3, BRKAWY, 2.54mm, TIN, R/A,
ROHS
SAMTEC TSW-103-08-T-D-RA
1 D1 LED, SMD, 0805, GREEN, CLEAR, 10mcd, 2.1V, 20mA,
570nm, ROHS
CHICAGO MINIATURE CMD17-21VGC/TR8
1 U1 IC-25A DC/DC, PWR MODULE, 40P, HDA, 17x19,
ROHS
INTERSIL ISL8277MAIRZ
1 Q1 TRANSISTOR, N-CHANNEL, 3LD, SOT-23, 60V,
115mA, ROHS
DIODES, INC. 2N7002-7-F
0 R2, R5, R6,
R7, R8
RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE
HOLDER
4 R3, R9, R10,
R14
RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS VENKEL CR0603-10W-000T
1 R12 RES, SMD, 0603, 1k, 1/10W, 1%, TF, ROHS PANASONIC ERJ-3EKF1001V
2 R1, R11 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS VENKEL CR0603-10W-1002FT
1 R4 RES, SMD, 0603, 4.7k, 1/10W, 1%, TF, ROHS YAGEO 9C06031A4701FKHFT
1 R15 RES, SMD, 0603, 4.99k, 1/10W, 1%, TF, ROHS PANASONIC ERJ-3EKF4991V
1 R13 RES, SMD, 1206, 200Ω, 1/4W, 1%, TF, ROHS PANASONIC ERJ-8ENF2000V
1 SW1 SWITCH-TOGGLE, THRU-HOLE, SPDT, 5P, ROHS ITT CANNON GT11MCBE
2 J8, J9 HDWARE, MTG, CABLE TERMINAL, 6-14AWG,
LUG&SCREW, ROHS
BERG/FCI KPA8CTP

UG115 Rev.0.00 Page 10 of 16
Jul 28, 2017
ISL8277MEVAL1Z 3. PCB Layout Guidelines
3.4 ISL8277MEVAL1Z Board Layout
4BOTTOM
FOUR
CORNERS
BUMPONS, 0.44inW x 0.20inH, DOMETOP, BLACK 3M SJ-5003SPBL
1 PLACE ASSY
IN BAG
BAG, STATIC, 5x8, ZIPLOC, ROHS INTERSIL 212403-013
0 J7 DO NOT POPULATE OR PURCHASE
1 AFFIX TO
BACK OF
PCB
LABEL-DATE CODE_LINE 1: YRWK/REV#, LINE 2:
BOM NAME
INTERSIL LABEL-DATE CODE
Figure 5. PCB - Top Silk Screen
Qty
Reference
Designator Description Manufacturer
Manufacturer
Part