LTM8005

18

8005f

For more information www.linear.com/LTM8005

8005 F10

CTRL2

CTRL1

RT

SS

VC

FB

GND

GND

GND

GND/THERMAL VIAS

ISN

SW

AUX

RAMP

PWM

OVLO

GND

TO LED

STRING

TO LED STRING

CATHODE (BOOST)

GND

(OPTIONAL

DIODE)

IVINP

EN/UVLO

IVINN

LED

APPLICATIONS INFORMATION

Figure10. Layout Showing Suggested External Components, GND Plane and Thermal Vias for a Buck-Boost Mode Application

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

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

Avoid breaking the ground connection between the

external components and the LTM8005.

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 con-

nection and thermal path to the internal planes of the

printed circuit board. Pay attention to the location and

density of the thermal vias in Figures 9 and 10. The

LTM8005 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.