8

Power Dissipation

Package power dissipation is mainly a function of the

switching frequency and total gate charge of the selected

MOSFETs. Calculating the power dissipation in the driver for

a desired application is critical to ensuring safe operation.

Exceeding the maximum allowable power dissipation level

will push the IC beyond the maximum recommended

operating junction temperature of 125°C. The maximum

allowable IC power dissipation for the SO-8 package is

approximately 800mW. When designing the driver into an

application, it is recommended that the following calculation

be performed to ensure safe operation at the desired

frequency for the selected MOSFETs. The power dissipated

by the driver is approximated as:

MOSFET selection and any external capacitance added to

of the driver and is typically negligible.

+

() I

+

=

FIGURE 7. POWER DISSIPATION vs FREQUENCY

FREQUENCY (kHz)

1000

900

800

700

600

500

400

300

200

100

0

0

200

400

600

800 1000 1200

1600

1400

1800 2000

ISL6209