IR3894MTR1PBF International Rectifier, IR3894MTR1PBF Datasheet - Page 37

• Manufacturer Part Number: IR3894MTR1PBF
• Description: 12A Highly Integrated Single-Input Voltage, Synchronous Buck Regulator in a PQFN package.
• Manufacturer: International Rectifier

Specifications of IR3894MTR1PBF

• Part Status: Active and Preferred
• Package: PQFN / 5 x 6
• Circuit: Single Output
• Iout (a): 12
• Switch Freq (khz): 0 - 1500
• Input Range (v): 1.0 - 16
• Output Range (v): 0.5 - 12
• Pbf: PbF Option Available

Compensation parts
should be placed
as close as possible
to the Comp pin
Resistor Rt and Vref
decoupling cap should
be placed as close as
possible to their pins
LAYOUT RECOMMENDATIONS
The layout is very important when designing high
frequency switching converters. Layout will affect noise
pickup and can cause a good design to perform with less
than expected results.
Make the connections for the power components in the
top layer with wide, copper filled areas or polygons. In
general, it is desirable to make proper use of power
planes and polygons for power distribution and heat
dissipation.
The inductor, output capacitors and the IR3899 should be
as close to each other as possible. This helps to reduce
the EMI radiated by the power traces due to the high
switching currents through them. Place the input
capacitor directly at the PVin pin of IR3899.
The feedback part of the system should be kept away
from the inductor and other noise sources.
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FEBRUARY 01, 2012 | DATA SHEET | Rev 3.0
Figure 46a: IRDC3894 Demo board Layout Considerations – Top layer
Single‐Input Voltage, Synchronous Buck Regulator
- 37 -`
12A Highly Integrated SupIRBuck
The critical bypass components such as capacitors for
Vin, Vcc and Vref should be close to their respective pins.
It is important to place the feedback components
including feedback resistors and compensation
components close to Fb and Comp pins.
In a multilayer PCB use one layer as a power ground
plane and have a control circuit ground (analog ground),
to which all signals are referenced. The goal is to localize
the high current path to a separate loop that does not
interfere with the more sensitive analog control function.
These two grounds must be connected together on the
PC board layout at a single point. It is recommended to
place all the compensation parts over the analog ground
plane in top layer.
The Power QFN is a thermally enhanced package. Based
on thermal performance it is recommended to use at
least a 4‐layers PCB. To effectively remove heat from the
device the exposed pad should be connected to the
ground plane using vias. Figures 46a‐d illustrates the
implementation of the layout guidelines outlined above,
on the IRDC3899 4‐layer demo board.
Enough copper & minimum
ground length path between
Input and Output
All bypass caps should be
placed as close as possible
to their connecting pins
Switch N ode
IR3894
PD‐97745