Specifications

9
Dec. 20
Mitsubishi IPM-series Application Note
Correct and Safety Use of Power Module
Cautions
Mounting
When mounting a module on a heat sink, a device could get damage or degrade if a sudden torque ("one side
tightening ") is applied at only one mounting terminal, since stress is applied on a ceramic plate and silicon
chips inside the module. Shown in Fig.6.1 is the recommended torquing order for mounting screws.
Ԙ
Ԙ
Ԙ
ԙ
ԙ
ԙ
Ԛ
Ԛ
ԛ
ԛ
Ԝ
ԝ
Ԟ
ԟ
a) Two point mounting type b) four point mounting type c) eight point mounting type
Temporary tightening :Ԙψԙ ԘψԙψԚψԛ ԘψԙψԚψԛψԜψԝψԞψԟ
Final tightening :ԙψԘ ԛψԚψԙψԘ ԘψԙψԚψԛψԜψԝψԞψԟ
Fig.6.1
The recommended torquing order for mounting screws
*:Temporary tightening torque should be set at 20∼30% of maximum rating.
Also, care must be taken to achieve maximum contact (i.e. minimum contact thermal resistance) for the best
heat dissipation.)
The flatness of a heat sink where a module is mounted (ref.Fig.6.2) should be as follows. Also, the surface
finish should be less than Rz12s.
Copper base plate module:−100μm∼+100μm
Thermal compound with good thermal conductivity should be applied evenly about Aluminum base plate
modules:−100μm∼+200μm on the contact surface of a module and a heat sink.
Heat sink flatness: Less than ± 20 micrometers on a length of 100mm
/Less than 10 micrometers of roughness
Thermal grease thickness: +50∼+100μm
Grease on the contact surface prevents the corrosion of the contact surface. However, use the kind of
grease that has a stable characteristic over the whole operating temperature range and does not change its
properties for several years.
A torque wrench shall be used in tightening mounting screws and tighten screws to the specified torque.
Excessive torquing may result in damage or degradation of a device.
Power Module
The edge line of base plate
Grease applied area
− Concave
+ Convex
Specified range of
heat sink flatness
Fig.6.2 Heat Sink Flatness