Datasheet

LTM8028
15
8028fa
For more information www.linear.com/LTM8028
minimize EMI and 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 4
for a suggested layout. Ensure that the grounding and
heat sinking are acceptable.
A few rules to keep in mind are:
1. Place the R
T
resistor as close as possible to its respec-
tive pins.
2.
Place the C
IN
capacitor as close as possible to the V
IN
and GND connection of the LTM8028.
3. Place the C
OUT
capacitors as close as possible to the
V
OUT
and GND connection of the LTM8028.
4. Place the C
IN
, C
BKV
and C
OUT
capacitors such that their
ground current flow directly adjacent or underneath the
LTM8028.
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 LTM8028.
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 4. The LTM8028 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.
applicaTions inForMaTion
Figure 4. Layout Showing Suggested External Components, GND Plane and Thermal Vias
SENSEP
(OUTPUT IS
SET TO 1.55V)
GND
BKV
C
BKV
C
OUT
V
OUT
RUN
C
IN
8028 F04
V
IN
GND
THERMAL VIAS
GND
RT
SS SYNC
I
MAX
TEST
MARGA
PGOOD
V
O0
V
O1
V
O2
V
OB