LTM8067

13

8067fc

For more information www.linear.com/LTM8067

APPLICATIONS INFORMATION

PCB Layout

Most of the headaches associated with PCB layout have

been alleviated or even eliminated by the high level of

integration of the LTM8067. The LTM8067 is neverthe-

less a switching power supply, and care must be taken to

minimize electrical noise to ensure proper operation. Even

with the high level of integration, you may fail to achieve

specified operation with a haphazard or poor layout. See

Figure 1 for a suggested layout. Ensure that the grounding

and heat sinking are acceptable.

A few rules to keep in mind are:

tive pin.

and GND connections of the LTM8067.

ground current flow directly adjacent to or underneath

the LTM8067.

5. Connect all of the GND connections to as large a copper

pour or plane area as possible on the top layer. Avoid

breaking the ground connection between the external

components and the LTM8067.

6. Use vias to connect the GND copper area to the board’s

internal ground planes. Liberally distribute these GND

vias to provide both a good ground connection and

thermal path to the internal planes of the printed circuit

board. Pay attention to the location and density of the

thermal vias in Figure 1. The LTM8067 can benefit from

the heat sinking afforded by vias that connect to internal

GND planes at these locations, due to their proximity

to internal power handling components. The optimum

number of thermal vias depends upon the printed

circuit board design. For example, a board might use

very small via holes. It should employ more thermal

vias than a board that uses larger holes.

Figure 1. Layout Showing Suggested External Components, Planes and Thermal Vias

8067 F01

RUN

FB

LTM8067

THERMAL/INTERCONNECT VIAS