ISL6207

FN9075 Rev 8.00

Page 8 of 10

December 2, 2005

Thermal Management

For maximum thermal performance in high current, high

switching frequency applications, connecting the thermal pad

of the QFN part to the power ground with multiple vias, or

placing a low noise copper plane underneath the SOIC part is

recommended. This heat spreading allows the part to achieve

its full thermal potential.

Suppressing MOSFET Gate Leakage

With VCC at ground potential, UGATE and LGATE are high

impedance. In this state, any stray leakage has the potential to

deliver charge to either gate. If UGATE receives sufficient

charge to bias the device on (Note: Internal circuitry prevents

leakage currents from charging above 1.8V), a low impedance

path will be connected between the MOSFET drain and

PHASE. If the input power supply is present and active, the

system could see potentially damaging currents. Worst-case

leakage currents are on the order of pico-amps; therefore, a

10k

 resistor, connected from UGATE to PHASE, is more than

sufficient to bleed off any stray leakage current. This resistor

will not affect the normal performance of the driver or reduce its

efficiency.