LTM4641
APPLICATIONS INFORMATION—THERMAL CONSIDERATIONS AND
OUTPUT CURRENT DERATING
Table 4. 6V Output, Switching Frequency Noꢃinally 660kHz at Full Load
DERATING CURVE
Figure 21 to Figure 23
Figure 21 to Figure 23
Figure 21 to Figure 23
Figure 24 to Figure 26
Figure 24 to Figure 26
Figure 24 to Figure 26
V
POWER LOSS CURVE
Figure 18
AIRFLOW (LFꢁ)
HEAT SINK
None
θ
θ
θ
(°C/W)
IN
JA
12V, 24V, 36V
12V, 24V, 36V
12V, 24V, 36V
12V, 24V, 36V
12V, 24V, 36V
12V, 24V, 36V
0
10.1
8.2
6.8
8.1
6.5
5.5
Figure 18
200
400
0
None
Figure 18
None
Figure 18
BGA Heat Sink
BGA Heat Sink
BGA Heat Sink
Figure 18
200
400
Figure 18
Table 5. 3.3V Output, Switching Frequency Noꢃinally 360kHz at Full Load
DERATING CURVE
Figure 27 to Figure 30
Figure 27 to Figure 30
Figure 27 to Figure 30
Figure 31 to Figure 34
Figure 31 to Figure 34
Figure 31 to Figure 34
V
IN
POWER LOSS CURVE
Figure 19
AIRFLOW (LFꢁ)
HEAT SINK
None
(°C/W)
JA
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
0
10.4
8.4
7.1
8.6
6.8
5.8
Figure 19
200
400
0
None
Figure 19
None
Figure 19
BGA Heat Sink
BGA Heat Sink
BGA Heat Sink
Figure 19
200
400
Figure 19
Table 6. 1.5V Output, Switching Frequency Noꢃinally 315kHz at Full Load
DERATING CURVE
Figure 35 to Figure 38
Figure 35 to Figure 38
Figure 35 to Figure 38
Figure 39 to Figure 42
Figure 39 to Figure 42
Figure 39 to Figure 42
V
IN
POWER LOSS CURVE
Figure 20
AIRFLOW (LFꢁ)
HEAT SINK
None
(°C/W)
JA
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
6V, 12V, 24V, 36V
0
10.3
8.4
7.2
9.0
7.0
5.8
Figure 20
200
400
0
None
Figure 20
None
Figure 20
BGA Heat Sink
BGA Heat Sink
BGA Heat Sink
Figure 20
200
400
Figure 20
Table 7. Heat Sink Vendors (with Therꢃally Conductive Adhesive Tape Pre-Attached)
HEAT SINK ꢁANUFACTURER
Wakefield Engineering
Aavid Thermalloy
PART NUꢁBER
LTN20069
WEBSITE
www.wakefield.com
www.aavid.com
375424B00034G
Table 8. Therꢃally Conductive Adhesive Tape Vendor
THERꢁALLY CONDUCTIVE ADHESIVE
TAPE ꢁANUFACTURER
PART NUꢁBER
WEBSITE
Chomerics
T411
www.chomerics.com
4641f
44
Linear [ Linear ]
