AN4043 datasheet(53/60 Pages) STMICROELECTRONICS

53 / 60 page

AN4043

Design and mounting guidelines

Doc ID 022726 Rev 2

53/60

5.2

Mounting instructions and cooling techniques

The SLLIMM-nano is a very compact intelligent power module able to drive electric motors

up to 100 W without any heatsink or cooling system installed on the board. The NDIP is a

transfer mold package with no screw holes, therefore some dedicated cooling techniques

must be adopted if a higher power level is targeted.

One of the easiest methods is based on a natural cooling system and a proper design of the

PCB layout. In this case, the PCB, along with the pads, acts as a heatsink providing paths

for individual packages to effectively transfer heat to the board and the adjacent

environment. Therefore, maximizing the area of the metal traces where the power and

ground pins of the package are located is a valuable method for reducing the thermal

resistance and for leading to an improved power performance.

The pins mainly involved in this phenomenon are the positive DC pin (P) and the phase

output pins (U, V, W), since they are directly connected to the copper lead frame where the

power devices are mounted and IGBTs and diodes are the major source of heat, as already

treated in

Section 4: Power losses and dissipation. Several aspects impact on the total

thermal performance, such as the area of metal traces, the thickness of the copper plate,

their placement on the board and the distance between the SLLIMM-nano and other heat

Figure 36.

Example 2 on a possible wrong layout

AN4043 bảng dữ liệu(PDF) 53 Page - STMicroelectronics