Datasheet

LT1970
15
1970fe
For more information www.linear.com/LT1970
applicaTions inForMaTion
Figure 5. Examples of PCB Metal Used for Heat Dissipation. Driver Package Mounted on Top
Layer. Heat Sink Pad Soldered to Top Layer Metal. Metal Areas Drawn to Scale of Package Size
STILL AIR θ
JA
TSSOP
100°C/W
TSSOP
50°C/W
TSSOP
45°C/W
PACKAGE TOP LAYER 2ND LAYER 3RD LAYER BOTTOM LAYER
1970 F05a
AIRFLOW (LINEAR FEET PER MINUTE, lfpm)
–50
–60
REDUCTION IN
θ
JA
(%)
–30
–10
0
–40
–20
200 400 600 800
1970 F05b
10001000 300 500
Typical Reduction in
θ
JA
with
Laminar Airflow Over the Device
700 900
% REDUCTION RELATIVE
TO θ
JA
IN STILL AIR
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