en5366 Enpirion, en5366 Datasheet - Page 12

• Manufacturer Part Number: en5366
• Description: 6a Voltage Mode Synchronous Buck Pwm Dc-dc Converter With Integrated Inductor External Output Voltage Programming
• Manufacturer: Enpirion

September 2007
Layout Recommendations
Figure 5. Layout of power and ground copper.
Recommendation 1: Input and output filter
capacitors should be placed as close to the
EN5366QI package as possible to reduce EMI
from input and output loop currents.
reduces the physical area of the Input and
Output AC current loops.
Recommendation 2: Place a slit in the
input/output capacitor ground copper starting
just below the common connection point of the
device GND pins as shown in figures 5 and 6.
Recommendation 3: The large thermal pad
underneath the component must be connected
to the system ground plane through as many
vias as possible. The drill diameter of the vias
should be less than 0.33mm, and the vias must
have at least 1 oz. copper plating on the inside
wall, making the finished hole size around
0.26mm. This connection provides the path for
heat dissipation from the converter. Please see
figures 6, 7, and 8.
Recommendation
should be used to connect ground terminal of
the input capacitor and output capacitors to the
system ground plane as shown in figure 6.
©Enpirion 2007 all rights reserved, E&OE
V
V
Copper
Copper
OUT
OUT
(+)
(+)
Ground
Ground
Copper
Copper
Local
Local
input local ground
input local ground
Slit separating
Slit separating
4:
local ground
local ground
from output
from output
Copper
Copper
Multiple
V
V
IN
IN
(+)
(+)
small
This
vias
12
Figure 6. Use of thermal & noise suppression vias.
These vias can be the same size as the
thermal vias discussed in recommendation 3.
Recommendation 5: The system ground
plane referred to in recommendations 3 and 4
should be the first layer immediately below the
surface layer.
continuous
converter and the input/output capacitors
shown in figure 6.
Recommendation 6: As with any switch-mode
DC/DC converter, do not run sensitive signal or
control
package.
Please refer to the Gerber files and
summarized layout notes available on the
Enpirion website
layout details.
NOTE: Figures 5 and 6 show only the critical
components and traces for a minimum footprint
layout. ENABLE, Vout-programming, and
other small signal pins need to be connected
and routed according to the specific
application.
Compensation
Compensation
Test Points
Test Points
Vout
Vout
High-Frequency
High-Frequency
Noise Suppression
Noise Suppression
Vias
Vias
lines
and
This ground plane should be
www.enpirion.com
underneath
un-interrupted
PGND
PGND
Copper
Copper
Slit
Slit
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the
Vin
Vin
EN5366QI
below
for more
Thermal Pad
Thermal Pad
Vias and
Vias and
Soldermask
Soldermask
Opening
Opening
converter
AGND
AGND
Test
Test
Points
Points
the