LTM4622A
21
Rev B
APPLICATIONS INFORMATION
Figure 24 and Figure 25 show measured temperature
picture of the LTM4622A with no heat sink from 12V
input down to 3.3V and 5V output with 2A DC current on
each and from 12V down to 5V and 8V output with 2A
DC current on each. Both without heat sink and airflow.
SAFETY CONSIDERATIONS
The LTM4622A modules do not provide galvanic 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 thermal
shutdown and over current protection.
and without airflow. The derived thermal resistances in
Tables 2 to 6 for the various conditions can be multiplied
by the calculated power loss as a function of ambient
temperature to derive temperature rise above ambient,
thus maximum junction temperature. Room temperature
power loss can be derived from the efficiency curves in
the Typical Performance Characteristics section and ad-
justed with the above ambient temperature multiplicative
factors. The printed circuit board is a 1.6mm thick four
layer board with two ounce copper for the two outer layers
and one ounce copper for the two inner layers. The PCB
dimensions are 95mm × 76mm.
