ITF87012SVT Просмотр технического описания (PDF) - Intersil
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ITF87012SVT Datasheet PDF : 12 Pages
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ITF87012SVT
with no air flow. This graph provides the necessary
information for calculation of the steady state junction
temperature or power dissipation. Pulse applications can be
evaluated using the Intersil device Spice thermal model or
manually utilizing the normalized maximum transient thermal
impedance curve.
Displayed on the curve are RθJA values listed in the Electrical
Specifications table. The points were chosen to depict the
compromise between the copper board area, the thermal
resistance and ultimately the power dissipation, PDM.
Thermal resistances corresponding to other copper areas can
be obtained from Figure 20 or by calculation using Equation 2.
RθJA is defined as the natural log of the area times a coefficient
added to a constant. The area, in square inches is the top
copper area including the gate and source pads.
RθJA = 120.6 – 18.9 ln (Area)
(EQ. 2)
The transient thermal impedance (ZθJA) is also effected by
varied top copper board area. Figure 21 shows the effect of
copper pad area on single pulse transient thermal
impedance. Each trace represents a copper pad area in
square inches corresponding to the descending list in the
graph. Spice and SABER thermal models are provided for
each of the listed pad areas.
Copper pad area has no perceivable effect on transient
thermal impedance for pulse widths less than 100ms. For
pulse widths less than 100ms the transient thermal
impedance is determined by the die and package. Therefore,
CTHERM1 through CTHERM5 and RTHERM1 through
RTHERM5 remain constant for each of the thermal models. A
listing of the model component values is available in Table 1.
260
240
ln RθJA = 120.6- 18.9* (AREA)
220
218.4oC/W - 0.0056in2
200
198.2oC/W - 0.0163in2
180
160
140
120
0.001
0.01
0.1
1.0
AREA, TOP COPPER AREA (in2)
FIGURE 20. THERMAL RESISTANCE vs MOUNTING PAD AREA
200
COPPER BOARD AREA - DESCENDING ORDER
0.02 in2
160
0.05 in2
0.10 in2
0.25 in2
120 0.40 in2
80
40
0
10-1
100
101
102
103
t, RECTANGULAR PULSE DURATION (s)
FIGURE 21. THERMAL IMPEDANCE vs MOUNTING PAD AREA
7
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