LTM4606 LINER [Linear Technology], LTM4606 Datasheet - Page 14

• Manufacturer Part Number: LTM4606
• Description: Ultralow EMI 28VIN, 6A DC/DC ?Module
• Manufacturer: LINER [Linear Technology]

LTM4606
APPLICATIONS INFORMATION
Thermal Considerations and Output Current Derating
In different applications, LTM4606 operates in a variety
of thermal environments. The maximum output current is
limited by the environment thermal condition. Suffi cient
cooling should be provided to help ensure reliable opera-
tion. When the cooling is limited, proper output current
derating is necessary, considering ambient temperature,
airfl ow, input/output condition, and the need for increased
reliability.
The power loss curves in Figures 6 and 7 can be used
in coordination with the load current derating curves in
Figures 8 to 15 for calculating an approximate θ
module. The graphs delineate between no heat sink, and
a BGA heat sink. Each of the load current derating curves
14
2.5
2.0
1.5
1.0
0.5
0
6
5
4
3
2
1
0
0
75
Figure 6. 1.5V Power Loss
1
Figure 9. BGA Heat Sink
5V
5V
5V
AMBIENT TEMPERATURE (°C)
IN
IN
IN
80
, 1.5V
, 1.5V
, 1.5V
OUTPUT CURRENT (A)
2
OUT
OUT
OUT
3
12V LOSS
, 0LFM
, 200LFM
, 400LFM
85
4
5
90
5V LOSS
6
4606 F06
4606 F09
95
7
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
6
5
4
3
2
1
0
0
70
0
JA
for the
1
Figure 7. 3.3V Power Loss
Figure 10. No Heat Sink
75
AMBIENT TEMPERATURE (°C)
OUTPUT CURRENT (A)
2
12V
12V
12V
80
IN
IN
IN
24V LOSS
3
, 1.5V
, 1.5V
, 1.5V
will lower the maximum load current as a function of the
increased ambient temperature to keep the maximum junc-
tion temperature of the power module at 125°C maximum.
Each of the derating curves and the power loss curve that
corresponds to the correct output voltage can be used to
solve for the approximate θ
has three curves that are taken at three different air fl ow
conditions. Tables 3 and 4 provide the approximate θ
for Figures 8 to 15. A complete explanation of the thermal
characteristics is provided in the thermal application note
AN110.
Safety Considerations
The LTM4606 modules do not provide isolation from V
V
OUT
OUT
OUT
OUT
4
85
, 0LFM
, 200LFM
, 400LFM
. There is no internal fuse. If required, a slow blow fuse
12V LOSS
5
90
6
4606 F07
4606 F10
95
7
6
5
4
3
2
1
0
6
5
4
3
2
1
0
70
75
JA
of the condition. Each fi gure
Figure 11. BGA Heat Sink
12V
12V
12V
5V
5V
5V
75
AMBIENT TEMPERATURE (°C)
AMBIENT TEMPERATURE (°C)
Figure 8. No Heat Sink
IN
IN
IN
80
IN
IN
IN
, 1.5V
, 1.5V
, 1.5V
, 1.5V
, 1.5V
, 1.5V
80
OUT
OUT
OUT
OUT
OUT
OUT
, 0LFM
, 200LFM
, 400LFM
85
, 0LFM
, 200LFM
, 400LFM
85
90
90
4606 F11
4606 F08
IN
4606f
JA
to
95
95