
AN823
Vishay Siliconix
10 s (max)
255 ? 260 _ C
140 ? 170 _ C
1 X 4 _ C/s (max)
217 _ C
60 s (max)
3-6 _ C/s (max)
3 _ C/s (max)
60-120 s (min)
Reflow Zone
Pre-Heating Zone
Maximum peak temperature at 240 _ C is allowed.
FIGURE 3. Solder Reflow Temperature and Time Durations
THERMAL PERFORMANCE
A basic measure of a device’s thermal performance is the
On-Resistance vs. Junction Temperature
junction-to-case thermal resistance, R q jc , or the
junction-to-foot thermal resistance, R q jf . This parameter is
measured for the device mounted to an infinite heat sink and
is therefore a characterization of the device only, in other
words, independent of the properties of the object to which the
device is mounted. Table 1 shows the thermal performance
of the TSOP-6.
TABLE 1.
Equivalent Steady State Performance—TSOP-6
Thermal Resistance R q jf 30 _ C/W
1.6
1.4
1.2
1.0
0.8
0.6
V GS = 4.5 V
I D = 6.1 A
? 50
? 25
0
25
50
75
100
125
150
SYSTEM AND ELECTRICAL IMPACT OF
TSOP-6
In any design, one must take into account the change in
MOSFET r DS(on) with temperature (Figure 4).
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2
T J ? Junction Temperature ( _ C)
FIGURE 4. Si3434DV
Document Number: 71743
27-Feb-04