Datasheet

LTM4627
23
4627fc
For more information www.linear.com/LTM4627
APPLICATIONS INFORMATION
Safety Considerations
The LTM4627 modules do not provide isolation from V
IN
to V
OUT
. There is no internal fuse. If required, a slow blow
fuse with a rating twice the maximum input current needs
to be provided to protect each unit from catastrophic
failure. The device does support overvoltage protection
and overcurrent protection.
Layout Checklist/Example
The high integration of the LTM4627 makes the PCB
board layout very simple and easy. However, to optimize
its electrical and thermal performance, some layout con
-
siderations are still necessary.
• Use large PCB copper areas for high current paths,
including V
IN
, GND and V
OUT
. It helps to minimize the
PCB conduction loss and thermal stress.
• Place high frequency ceramic input and output capaci
-
tors next to the V
IN
, GND and V
OUT
pins to minimize
high frequency noise.
• Place a dedicated power ground layer underneath the
unit.
• To minimize the via conduction loss and reduce module
thermal stress, use multiple vias for interconnection
between top layer and other power layers.
• Do not put vias directly on the pad, unless they are
capped or plated over.
• Place test points on signal pins for testing.
• Use a separated SGND ground copper area for com
-
ponents connected to signal pins. Connect the SGND
to GND underneath the unit.
•
For parallel modules, tie the COMP and V
FB
pins to-
gether. Use an internal layer to closely connect these
pins together.
Figure 17 gives a good example of the recommended
layout. LGA and BGA PCB layouts are identical with the
exception of circle pads for BGA (see Package Description).
Figure 17. Recommended PCB Layout
(LGA Shown, for BGA Use Circle Pads)
GND
V
IN
CONTROL
4627 F17
CONTROL
CONTROL
SIGNAL
GROUND
V
OUT
V
OUT
C
OUT
C
OUT
C
IN
C
IN