LTM4600 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTM4600' PDF : 24 Pages View PDF
LTM4600
applications information
VIN
VIN
VOUT
VOUT
LTM4600
(20AMAX)
PGND COMP VOSET SGND
RSET
COMP VOSET SGND
VIN
LTM4600 VOUT
PGND
4600 F07
Figure 7. Parallel Two µModules with Load Sharing
Thermal Considerations and Output Current Derating
The power loss curves in Figures 8 and 13 can be used
in coordination with the load current derating curves in
Figures 9 to 12, and Figures 14 to 15 for calculating an
approximate qJA for the module with various heat sink-
ing methods. Thermal models are derived from several
temperature measurements at the bench, and thermal
modeling analysis. Application Note 103 provides a detailed
explanation of the analysis for the thermal models, and the
derating curves. Tables 3 and 4 provide a summary of the
equivalent qJA for the noted conditions. These equivalent
qJA parameters are correlated to the measured values, and
improve with air-flow. The case temperature is maintained
at 100°C or below for the derating curves. This allows for
4W maximum power dissipation in the total module with
top and bottom heat sinking, and 2W power dissipation
through the top of the module with an approximate qJC
between 6°C/W to 9°C/W. This equates to a total of 124°C
at the junction of the device.
Safety Considerations
The LTM4600 modules do not provide isolation from VIN
to VOUT. There is no internal fuse. If required, a slow blow
fuse with a rating twice the maximum input current should
be provided to protect each unit from catastrophic failure.
Table 3. 1.5V Output
DERATING CURVE
Figures 9, 11
Figures 9, 11
Figures 9, 11
Figures 10, 12
Figures 10, 12
Figures 10, 12
VIN (V)
5, 12
5, 12
5, 12
5, 12
5, 12
5, 12
POWER LOSS CURVE
Figure 8
Figure 8
Figure 8
Figure 8
Figure 8
Figure 8
AIR FLOW (LFM)
0
200
400
0
200
400
HEAT SINK
None
None
None
BGA Heat Sink
BGA Heat Sink
BGA Heat Sink
qJA (°C/W)
15.2
14
12
13.9
11.3
10.25
Table 4. 3.3V Output
DERATING CURVE
Figure 14
Figure 14
Figure 14
Figure 15
Figure 15
Figure 15
VIN (V)
12
12
12
12
12
12
POWER LOSS CURVE
Figure 13
Figure 13
Figure 13
Figure 13
Figure 13
Figure 13
AIR FLOW (LFM)
0
200
400
0
200
400
HEAT SINK
None
None
None
BGA Heat Sink
BGA Heat Sink
BGA Heat Sink
qJA (°C/W)
15.2
14.6
13.4
13.9
11.1
10.5
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