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

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

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.

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.

Markings

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

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.

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.