User Guide 052
UG052.2
July 15, 2016
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Recommended Equipment
The following materials are recommended to perform testing:
• 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.
Functional Description
The ISL8018DEMO1Z board provides a simple platform for the
ISL8018.
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
C
OUT
, 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
FIGURE 2. TOP SIDE FIGURE 3. BOTTOM SIDE
