About IGBT IPMs (Intelligent Power Modules)Examples of Actual IGBT IPMs: Packages


Points of this article

・Actual IPMs are used as examples to describe package types, external dimensions, pin assignments, markings, and the method of mounting heat sinks.

In this article, IGBT IPM packages are explained. The IGB IPM examples used are, as in the previous article, models in the BM6437x series, which are ROHM’s 3rd-generation IGBT IPMs.

Examples of Actual IGBT IPMs: Packages

The package for the BM6437x series is HSDIP25, long pin type (suffix: -VA). The size of package, not including the pins, is 38.0 mm x 24.0 mm x 3.5 mm and it has 25 pins. Below, the external dimensions, pin assignments, markings, and heat sink mounting method are described.

External dimensions:HSDIP25(Long pin type, Suffix: -VA)
※Click on the dimension diagrams to enlarge

Pin Assignment

Below is a list of pin names and functions for pin numbers.

Pin No. Pin Name Function
1 NC Not connected (GND potential)
2 VBU U phase floating control supply
3 VBV V phase floating control supply
4 VBW W phase floating control supply
5 HINU U phase high side IGBT control
6 HINV V phase high side IGBT control
7 HINW W phase high side IGBT control
8 HVCC Control supply for HVIC
9 GND Ground (Note 1)
10 LINU U phase low side IGBT control
11 LINV V phase low side IGBT control
12 LINW W phase low side IGBT control
13 LVCC Control supply for LVIC
14 FO Alarm output
15 CIN Detecting of short circuit current trip voltage
16 GND Ground (Note 1)
17 VOT Temperature output
Pin No. Pin Name Function
18 NW W phase low side IGBT emitter
19 NV V phase low side IGBT emitter
20 NU U phase low side IGBT emitter
21 W W phase output
22 V V phase output
23 U U phase output
24 P Inverter supply
25 NC Not connected (Noet 2)

Note 1: There are two GND pins, which are pins 9 and 16, but these are connected within the IPM, so that externally only one of the pins should be connected (it is recommended that pin 16 be connected), and the other should be left in the open state.
Note 2: There are no electrical connections within the IPM.


The positions and meanings of markings are indicated. Markings are displayed on the bottom side, which is the side opposite the heat sink.

Insulation Distance

Insulation distances (clearance and creepage) are as follows.

Item Clearance [mm] Creepage [mm]
Between different-electrode charging pins 2.50 3.00
Between pins and heat sink 1.45 1.50

Heat Sink Mounting Method

When installing an IPM to a heat sink, if screws are fastened to greater than the prescribed torque, or if one screw is fastened too tightly, stress may be applied to the chips within the IPM and the heat-dissipating ceramic, possibly culminating in destruction, cracking, or degradation.

The bottom-left figure shows the order of fastening to be used. When fastening, a torque driver is used to fasten to the prescribed torque. The temporary fastening torque fastening should be set to around 20 to 30% of the prescribed maximum torque.

Grease with good thermal conductivity should be applied uniformly, to a thickness of about 100 to 200 µm, onto the surface of the heat sink that is to be in contact with the IPM heat-dissipating surface. The grease applied should not undergo degradation within the operating temperature range, and should resist aging. Please take care to ensure that foreign matter is not intermixed at the contact surfaces of the IPM and the heat sink.

After applying the grease, it is recommended to install the IPM directly to the heat sink with screws after applying the grease. When a heat-radiation sheet is used between the IPM heat-dissipating surface and the heat sink, depending on the thickness and the elastic modulus of the sheet, stresses may be brought to bear on the chips within the IPM and the heat-dissipating ceramic, resulting in destruction, cracking, or degradation. When using a heat-radiation sheet, please perform thorough evaluations to ensure that the marked surface of the IPM does not bow outward toward the + side as indicated in the drawing on the lower right.

The following are specifications for fastening torques and external heat sink flatness.

Item Specifications Unit Conditions
Min Typ Max
Fastening torque 0.59 0.69 0.78 N・m Mounting screw M3 Note 1 , recommended value 0.69 N・m
External heat sink flatness -50 +100 µm See ” External heat sink flatness measurement positions ” below

Note 1: Flat washers (JIS B1256 recommended) are to be used with mounting screws.

In order to obtain the maximum effect of heat dissipation, the contact area must be made as great as possible, and the contact thermal resistance must be minimized. The flatness (bowing/roughness) of the external heat sink is, at the IPM mounting surface, assumed to be as shown below.

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