ISL8033A INTERSIL [Intersil Corporation], ISL8033A Datasheet - Page 16

• Manufacturer Part Number: ISL8033A
• Description: Dual 3A Low Quiescent Current High Efficiency Synchronous Buck Regulator
• Manufacturer: INTERSIL [Intersil Corporation]

The inductor’s saturation current rating needs be at least
larger than the peak current. The ISL8033, ISL8033A
protects the typical peak current 4.8A. The saturation
current needs be over 4.8A for maximum output current
application.
ISL8033, ISL8033A uses an internal compensation
network and the output capacitor value is dependent on
the output voltage. The ceramic capacitor is
recommended to be X5R or X7R. The recommended
minimum output capacitor values for the ISL8033,
ISL8033A are shown in Tables 1 and 2 on page 2.
Output Voltage Selection
The output voltage of the regulator can be programmed
via an external resistor divider, which is used to scale the
output voltage relative to the internal reference voltage
and feed it back to the inverting input of the error
amplifier. Refer to Figure 1.
The output voltage programming resistor, R
Channel 2), will depend on the desired output voltage of
the regulator. The value for the feedback resistor is
typically between 0Ω and 750kΩ. Let R
R
For better performance, add 12pF in parallel to R
output voltage desired is 0.8V, then leave R
unpopulated and short R
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R
3
3
will be:
=
10/12/10
9/29/10
DATE
----------------------------------
V
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
OUT
R
2
x0.8V
–
0.8V
For information regarding Intersil Corporation and its products, see
REVISION
FN6854.1
FN6854.0
in the quality certifications found at
2
16
.
www.intersil.com/products
For additional products, see
In Table 3 on page 2, corrected F
Initial Release.
http://rel.intersil.com/reports/search.php
2
= 124kΩ, then
3
2
ISL8033, ISL8033A
ISL8033A
(or R
2
(EQ. 2)
. If the
5
in
for a complete list of Intersil product families.
www.intersil.com/product_tree
Input Capacitor Selection
The main functions for the input capacitor is to provide
decoupling of the parasitic inductance and to provide
filtering function to prevent the switching current flowing
back to the battery rail. One 22µF X5R or X7R ceramic
capacitor is a good starting point for the input capacitor
selection per channel.
PCB Layout Recommendation
The PCB layout is a very important converter design step
to make sure the designed converter works well. For
ISL8033, the power loop is composed of the output
inductor L’s, the output capacitor C
LX’s pins, and the SGND 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 LX_ 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 closely as possible to
the VIN pin . Also, the ground of the input and output
capacitors should be connected as closely 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.
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SW
www.intersil.com/askourstaff
for ISL8033 from 1Hz to 1MHz
CHANGE
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OUT1
and C
October 21, 2010
OUT2
FN6854.1
, the