LTM4625
APPLICATIONS INFORMATION
Safety Considerations
The LTM4625 modules do not provide galvanic isolation
from VIN to VOUT. 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 thermal
shutdown and over current protection.
Layout Checklist/Example
The high integration of LTM4625 makes the PCB board
layout very simple and easy. However, to optimize its
electrical and thermal performance, some layout consid-
erations are still necessary.
• Use large PCB copper areas for high current paths,
including VIN, GND and VOUT. It helps to minimize the
PCB conduction loss and thermal stress.
• Place high frequency ceramic input and output capaci-
tors next to the VIN, PGND and VOUT 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 via directly on the pad, unless they are
capped or plated over.
• Use a separated SGND ground copper area for com-
ponents connected to signal pins. Connect the SGND
to GND underneath the unit.
• Bring out test points on the signal pins for monitoring.
• Keep separation between CLKIN, CLKOUT and FREQ pin
traces to minimize possibility of noise due to crosstalk
between these signals.
Figure 19 gives a good example of the recommended layout.
GND
20
RFB
VIN
VOUT
COUT
GND
CIN
4625 F19
Figure 19. Recommended PCB Layout
Rev D
For more information www.analog.com