IP1827TRPBF International Rectifier, IP1827TRPBF Datasheet - Page 33

• Manufacturer Part Number: IP1827TRPBF
• Description: IC DC-DC REG SYNC BUCK LGA
• Manufacturer: International Rectifier
• Series: iPOWIR™r
• Type: Step-Down (Buck), PWM - Voltage Moder

Specifications of IP1827TRPBF

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.6 V ~ 12 V
• Current - Output: 25A
• Frequency - Switching: 225kHz ~ 1.65MHz
• Voltage - Input: 1.5 V ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: *
• Package / Case: *
• Package: LGA - 7.7 x 7.7
• Circuit: Single Output
• Iout (a): 25
• Switch Freq (khz): 250 - 1500
• Input Range (v): 1.5 - 16
• Output Range (v): 0.6 - 0.75*Vin
• Internal Bias Ldo: Yes
• Ocp Otp Uvlo Pre-bias Soft Start And: Remote Sense + Body Tracking + Temp Comp OCP
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LAYOUT CONSIDERATIONS
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 all 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 iP1827 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.
The input capacitors should be placed as close as possible
to the PGnd pad. The connection of the Vin pad to the Vin
power polygon should be low impedance, using several
vias in parallel. The layout must ensure minimum length
ground path and enough copper for input and output
capacitors with a direct connection.
The iP1827 has a local power ground pad called Bias Gnd
(pin 12) for bypassing Vcc or PVcc supplies. The analog or
signal ground, LGnd, is used as a separate control circuit
ground to which all signals are referenced. The analog
Resistors Rt (marked in Brown)
should be placed as close as
should be placed as close as
(Marked in Cyan) should be
placed as close as possible
possible to the Comp pin
to their connecting pins
Single Point Connection
33
ground path between
of AGND and BiasGnd
(Marked in dark blue)
possible to their pins
Compensation parts
& minimum length
Input and Output
Enough copper
All bypass caps
January 24, 2011 | V1.2
BiasGnd
Figure 35a: IRDC1827 demoboard layout considerations – Top Layer
Switch node should have small area and
should be localized to Top layer
Highly Integrated 25A Single‐input Voltage,
Synchronous Buck Regulator
ground polygon should be connected to BiasGnd through
a single point connection using a 0 ohm resistor, at a
location away from noise sources. The PGnd pad (Pin 3)
should be connected to system power Ground.
In order to minimize coupling switching noise into other
layers, the area of the switch node copper should be kept
small. It is also advisable to keep the switch node copper
localized to the top layer.
The critical bypass components such as capacitors for
Vcc 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.
A pair of sense traces running very close to each other and
away from any noise sources should be used to implement
true differential remote sensing of the voltage.
If remote sense is not used, the output voltage sense trace
used for feedback should be tapped from a low impedance
point such as directly from an output capacitor.
The iPOWiR package is a thermally enhanced package.
Based on thermal performance it is recommended to
use at least a 6‐layers PCB. Figures 25A‐f illustrate the
implementation of the layout guidelines outlined above,
on the IRDC1827 6 layer demoboard.
Optional on board
load transient circuit:
Not Critical
Switch node should
have small area and
should be localized
to Top layer
iP1827
97599