Datasheet
V
IN
V
OUT
GND
L1
C1
C2
R1
R2
GND
Enable
V
IN
V
OUT
TPS61220, TPS61221, TPS61222
SLVS776A –JANUARY 2009–REVISED APRIL 2014
www.ti.com
12 Layout
12.1 Layout Guidelines
As for all switching power supplies, the layout is an important step in the design, especially at high peak currents
and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as
well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground
paths. The input and output capacitor, as well as the inductor should be placed as close as possible to the IC.
The feedback divider in an application using the TPS61220 should be placed as close as possible to the control
ground pin of the IC. To route the ground path from the resistor divider, use short traces as well, separated from
the power ground traces. This avoids ground shift problems, which can occur due to superimposition of power
ground current and control ground current. Assure that the ground traces are connected close to the device GND
pin.
12.1.1 Thermal Information
Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires
special attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added
heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-
dissipation limits of a given component.
Three basic approaches for enhancing thermal performance are listed below.
• Improving the power-dissipation capability of the PCB design
• Improving the thermal coupling of the component to the PCB
• Introducing airflow in the system
For more details on how to use the thermal parameters in the dissipation ratings table please check the Thermal
Characteristics Application Note (SZZA017) and the IC Package Thermal Metrics Application Note (SPRA953).
12.2 Layout Example
Figure 28. PCB Layout Suggestion For Adjustable Output Voltage Options
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Product Folder Links: TPS61220 TPS61221 TPS61222