MODE

ENABLE

C

I

L

V

IN

C

O

V

OUT

GND

J(MAX)

A

D(MAX)

JA

T

- T

105 C - 85 C

P

=

=

= 160mW

R

125 C/W

q

°

°

°

TPS62690

TPS62691

TPS62697

www.ti.com

SLVS965B

– MARCH 2011 – REVISED JANUARY 2012

LAYOUT CONSIDERATIONS

As for all switching power supplies, the layout is an important step in the design. High-speed operation of the

TPS6269x devices demand careful attention to PCB layout. Care must be taken in board layout to get the

specified performance. If the layout is not carefully done, the regulator could show poor line and/or load

regulation, stability and switching frequency issues as well as EMI problems. It is critical to provide a low

inductance, impedance ground path. Therefore, use wide and short traces for the main current paths.

The input capacitor should be placed as close as possible to the IC pins as well as the inductor and output

capacitor. In order to get an optimum ESL step, the output voltage feedback point (FB) should be taken in the

output capacitor path, approximately 1mm away for it. The feed-back line should be routed away from noisy

components and traces (e.g. SW line).

Figure 36. Suggested Layout (Top)

THERMAL INFORMATION

Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires

special attention to power dissipation. Many system-dependant 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 into the system

(3)

Copyright

© 2011–2012, Texas Instruments Incorporated

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