L6208PD datasheet(27/35 Pages) STMICROELECTRONICS

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L6208

Application information

Figure 29. IC power dissipation versus output current in MICROSTEPPING mode

8.2

Thermal management

In most applications the power dissipation in the IC is the main factor that sets the maximum

current that can be delivered by the device in a safe operating condition. Therefore, it has to

be taken into account very carefully. Besides the available space on the PCB, the right

package should be chosen considering the power dissipation. Heat sinking can be achieved

using copper on the PCB with proper area and thickness. Figure 30, 31 and 32 show the

junction to ambient thermal resistance values for the PowerSO36, PowerDIP24 and SO24

packages.

For instance, using a PowerSO package with a copper slug soldered on a 1.5 mm copper

thickness FR4 board with a 6 cm2 dissipating footprint (copper thickness of 35 µm),

the Rth(j-amb) is about 35 °C/W. Figure 33 shows mounting methods for this package. Using

a multilayer board with vias to a ground plane, thermal impedance can be reduced down to

15 °C/W.

Figure 30. PowerSO36 junction ambient thermal resistance versus on-board copper

area

L6208PD データシート(PDF) 27 Page - STMicroelectronics