MJE18008, MJF18008
www.onsemi.com
8
MOUNTED
FULLY ISOLATED
PACKAGE
LEADS
HEATSINK
0.110″ MIN
Figure 22a. Screw or Clip Mounting Position
for Isolation Test Number 1
*Measurement made between leads and heatsink with all leads shorted together
CLIP
MOUNTED
FULLY ISOLATED
PACKAGE
LEADS
HEATSINK
CLIP
0.099″ MIN
MOUNTED
FULLY ISOLATED
PACKAGE
LEADS
HEATSINK
0.099″ MIN
Figure 22b. Clip Mounting Position
for Isolation Test Number 2
Figure 22c. Screw Mounting Position
for Isolation Test Number 3
TEST CONDITIONS FOR ISOLATION TESTS*
4-40 SCREW
PLAIN WASHER
HEATSINK
COMPRESSION WASHER
NUT
CLIP
HEATSINK
Laboratory tests on a limited number of samples indicate, when using the screw and compression washer mountin
technique, a screw torque of 6 to 8 in
.
lbs is sufficient to provide maximum power dissipation capability. The compres
sion washer helps to maintain a constant 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 exces
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 adversel
affecting the package. However, in order to positively ensure the package integrity of the fully isolated device, ON Semi
conductor does not recommend exceeding 10 in
.
lbs of mounting torque under any mounting conditions.
Figure 23. Typical Mounting Techniques
for Isolated Package
Figure 23a. Screw−Mounted Figure 23b. Clip−Mounted
**For more information about mounting power semiconductors see Application Note AN1040.
