Intersil ISL6442 User Manual

ISL6442 Dual PWM and Linear Controller Evaluation
Board User Guide
This application note describes how to use the ISL6442EVAL1Z
(Rev. C) board to evaluate the ISL6442 dual switching
regulator, plus one linear regulator. Refer to the schematic,
BOM (Bill of Materials), and board layout (at the end of this
document), as needed. The ISL6442 datasheet
a reference.
Configuration
The outputs are set up as follows:
• Switcher V = 1.8V @ 3A (with V
OUT1
• Switcher V = 3.3V @ 3A (with V
OUT2
• Linear V = 5.0V @ 0.3A (with V
OUT3
The outputs are switching at ~1.4MHz rate, based on the
resistor selected on the RT pin.
The current range for the switcher output that is presently
supported is limited by the FETs used. The FDS6912A dual FET
(in SO-8 package) can handle up to 3A. However, the ISL6442
gate drivers are capable of driving discrete upper and lower
FETs for up to 25A output current as well, even though not
supported on this board.
The linear output supports ~1W. The output current capability
of the linear regulator is determined mainly by the power
dissipation of the FET as mounted:
PV = (V -V )*I .
OUT3 IN3 OUT3 OUT3
FIGURE 1. ISL6442EVAL1Z BOARD PHOTO
November 28, 2011
AN1181.1
is also used as
= 6V)
IN
= 6V)
IN
= 6V)
IN3
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
Quick Start Evaluation
Figure 1 shows a photo of the populated board, and Figure 2
shows a plot of the top layer for reference, and details the
available input and output connections. Two switchers share
one input V . The linear regulator has separate turrets for its
IN
input (V ) and GND. Each output has turrets for VOUT and
IN3
GND, plus a scope probe socket, for low noise waveforms.
V = 6V
IN
V
OUT1
test
point
V LOAD
OUT1
V
IN3
FIGURE 2. ISL6442EVAL1Z INPUT AND OUTPUT CONNECTIONS
Quick Start Setup (Light Load)
For a quick and easy test, one 6V supply is needed. Connect P1
(V ) and P7 (V ) to each other, and to the 6V supply; connect
IN IN3
the supply GND to P2 and P9. Attach light loads to each
output.
Switch on the power supply; all three outputs should turn on to
their expected DC values; use a voltmeter or oscilloscope to
view them. VOUT1 and VOUT2 will have a ramp time of a few
milliseconds (VOUT3 will be much faster).
Note that the IC and all three inputs are sharing one supply
voltage in this simple example. The linear V
different, since it has its own input posts.
Board Features and Modifications
Heavier loads can be evaluated by placing them across the
appropriate output to GND. Resistors, electronic loads, or
Copyright Intersil Americas Inc. 2011. All Rights Reserved.
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All other trademarks mentioned are the property of their respective owners.
Application Note 1181
Author: Pengju Kong
I
out
A
+
V V
_
V
out
V
OUT2
= 6V V LOAD
OUT3
can certainly be
IN3
V
OUT2
test
point
LOAD