isl8018demo1z user guide

User Guide 052
ISL8018DEMO1Z Demonstration Board User Guide
Description
Key Features
The ISL8018DEMO1Z is intended for use by individuals with
requirements for point-of-load applications sourcing from 2.7V
to 5.5V. The ISL8018DEMO1Z simple smallest factor
demonstration board is used for a quick and easy
demonstration of the performance of the ISL8018 low
quiescent high efficiency synchronous buck regulator.
• High efficiency synchronous buck regulator with up to 97%
efficiency
The ISL8018DEMO1Z is a 20.07mmx16.51mm 4-layer FR4
board with 2oz copper in all layers. The complete converter
occupies 115.613mm2 area.
• Internal soft-start - 1ms or adjustable
References
• External synchronization up to 4MHz - master to slave phase
shifting capability
• ±10% output voltage margining
• Adjustable current limit
• Start-up with prebiased output
• Soft-stop output discharge during disabled
• Adjustable frequency from 500kHz to 4MHz - default at 1MHz
ISL8018 Datasheet
Ordering Information
PART NUMBER
ISL8018DEMO1Z
DESCRIPTION
Demonstration board
ISL8018
VIN
VIN
GND
FS
EN
PHASE
VOUT
GND
PG
EPAD
PGND
SYNCIN
SGND
SYNCOUT
COMP
ISET
SS
VSET
FB
FIGURE 1. ISL8018DEMO1Z BLOCK DIAGRAM
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
User Guide 052
Recommended Equipment
Functional Description
The following materials are recommended to perform testing:
The ISL8018DEMO1Z board provides a simple platform for the
ISL8018.
• 0V to 10V power supply with at least 15A source current
capability or 5V battery
• Electronic loads capable of sinking current up to 10A
• Digital Multimeters (DMMs)
• 100MHz quad-trace oscilloscope
• Signal generator
Quick Setup Guide
1. Ensure that the circuit is correctly connected to the supply and
loads prior to applying any power.
2. Connect the bias supply to VIN, the plus terminal to VIN and
the negative return to PGND.
3. Connect the output load to VOUT, the plus terminal to VO and
the negative return to PGND.
4. Verify the output voltage is 1.8V for VO.
This device is a monolithic, synchronous step-down DC/DC
converter that can deliver up to 8A of continuous output current
from 2.7V to 5.5V input supply. It uses peak current mode control
architecture to allow low duty cycle operation. The device operates
at 1MHz switching frequency.
PCB Layout Guidelines
The PCB layout is a very important converter design step to make
sure the designed converter works well. For ISL8018, the power
loop is composed of the output inductor L’s, the output capacitor
COUT, the PHASE pins and the PGND pin. It is necessary to make
the power loop as small as possible and the connecting traces
among them should be direct, short and wide. The switching
node of the converter, the PHASE pins and the traces connected
to the node are very noisy, so keep the voltage feedback trace
away from these noisy traces. The input capacitor should be
placed as close as possible to the VIN pin and the ground of the
input and output capacitors should be connected as close as
possible. The heat of the IC is mainly dissipated through the
thermal pad. Maximizing the copper area connected to the
thermal pad is preferable. In addition, a solid ground plane is
helpful for better EMI performance. It is recommended to add at
least 5 vias ground connection within the pad for the best
thermal relief.
ISL8018DEMO1Z Demonstration Board
ISL8018DEMO1Z
FIGURE 2. TOP SIDE
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FIGURE 3. BOTTOM SIDE
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ISL8018DEMO1Z Schematic
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FIGURE 4. ISL8018DEMO1Z SCHEMATIC
Bill of Materials
REFERENCE
DESIGNATOR
QTY UNITS
DESCRIPTION
MANUFACTURER
MANUFACTURER PART
1
ea
ISL8018DEMO1ZPCB
IMAGINEERING
INC.
ISL8018DEMO1ZPCB
C7
1
ea
CAP, SMD, 0402, 15pF, 50V, 5%, NP0, ROHS
MURATA
GRM36COG150J050AQ
C1, C2, C3, C4,
C5, C6
6
ea
CAP, SMD, 1206, 22µF, 6.3V, 20%, X5R, 1.6mm Height, ROHS
TDK
C3216X5R0J226M160AA
L1
1
ea
COIL-PWR INDUCTOR, SMD, 7x6.9, 0.76µH, 20%, 15.5A, 2.25mΩ,
ROHS
Wurth Electronics
744314076
VO, VIN
2
ea
CONN-MINI TEST PT, VERTICAL, RED, ROHS
KEYSTONE
5000
P1, P2
2
ea
CONN-MINI TEST PT, VERTICAL, BLK, ROHS
KEYSTONE
5001
U3
1
ea
IC-ADJ. 8A BUCK REGULATOR, 20P, QFN, 3X4, ROHS
INTERSIL
ISL8018IRAJZ
R3
1
ea
RES, SMD, 0402, 0Ω, 1/16W, 5%, TF, ROHS
VENKEL
H2510-00R00-1/16W-T
R2
1
ea
RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ2RKF1003
R1
1
ea
RES, SMD, 0402, 200k, 1/16W, 1%, TF, ROHS
ROHM
MCR01MZPF2003
R4
0
ea
RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS
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ISL8018DEMO1Z
Board Layout
FIGURE 5. TOP COMPONENTS
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FIGURE 6. BOTTOM SILK SCREEN
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Typical Performance Curves
VIN = 5.5V, VOUT = 1.8V, IOUT = 8A
VIN 2V/DIV
IOUT 2A/DIV
VIN 2V/DIV
VOUT 1V/DIV
IOUT 2A/DIV
VOUT 1V/DIV
1ms/DIV
200µs/DIV
FIGURE 7. VIN AT FULL LOAD
FIGURE 8. SHUTDOWN WITH VIN AT FULL LOAD
C2 20mV/DIV
1µs/DIV
FIGURE 9. VOUT RIPPLE ACROSS THE OUTPUT CAPS
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 document is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
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