MJF6388_08 Datasheet, PDF (7/8 Pages) ON Semiconductor – Complementary Power Darlingtons

MJF6388 (NPN), MJF6668 (PNP)
TEST CONDITION FOR ISOLATION TEST*
FULLY ISOLATED PACKAGE
LEADS
HEATSINK
0.110, MIN
Figure 14. Mounting Position
*Measurement made between leads and heatsink with all leads shorted together.
MOUNTING INFORMATION
4-40 SCREW
CLIP
PLAIN WASHER
HEATSINK
COMPRESSION WASHER
NUT
HEATSINK
Figure 15. Typical Mounting Techniques*
Laboratory tests on a limited number of samples indicate, when using the screw and compression washer mounting technique, a screw
torque of 6 to 8 in ^. lbs is sufficient to provide maximum power dissipation capability. The compression washer helps to maintain a con-
stant pressure on the package over time and during large temperature excursions.
Destructive laboratory tests show that using a hex head 4−40 screw, without washers, and applying a torque in excess of 20 in ^. lbs will
cause the plastic to crack around the mounting hole, resulting in a loss of isolation capability.
Additional tests on slotted 4−40 screws indicate that the screw slot fails between 15 to 20 in ^. lbs without adversely affecting the pack-
age. However, in order to positively ensure the package integrity of the fully isolated device, ON Semiconductor does not recommend
exceeding 10 in ^. lbs of mounting torque under any mounting conditions.
** For more information about mounting power semiconductors see Application Note AN1040.
http://onsemi.com
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