AN3338 datasheet(67/72 Pages) STMICROELECTRONICS

Part #	AN3338

Description	In recent years the variable speed motor control market has required high performance

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

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Doc ID 18441 Rev 4

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AN3338

Design and mounting guidelines

5.2.2

Mounting torque

While mounting the SLLIMM to a heatsink make sure not to apply excessive force during the

assembly.

Table 14 provides the specified fastening torque. Inappropriate mounting can

damage the device and over tightening the screws may cause DBC substrate or molding

compound cracks. Avoid mechanical stress due to tightening on one side only. It is

recommended to temporarily fasten both screws, then fasten them permanently to the

specified torque value using a torque wrench.

Figure 47 shows the screw fastening order.

Figure 45. Recommended silicon grease thickness and positioning

Heatsink

100~200 m

thickness

SLLIMM

Table 14. Mounting torque and heatsink flatness

Parameter

Limits

Units

Min.

Typ.

Max.

Mounting torque (M3 screw)

0.4

0.7

1.0

Heatsink flatness

-50

150

µm

SDIP-25L package weight

SDIP-38L package weight

AN3338 Datasheet(PDF) 67 Page - STMicroelectronics