ISL6566 datasheet(27/30 Pages) RENESAS

Part #	ISL6566

Description	Three-Phase Buck PWM Controller with Integrated MOSFET Drivers for VRM9, VRM10, and AMD Hammer Applications

PDF	30 Pages

Scroll/Zoom	100%

Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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27 / 30 page

ISL6566

FN9178 Rev 4.00

Page 27 of 30

Mar 9, 2006

Thermal Management

For maximum thermal performance in high current, high

switching frequency applications, connecting the thermal GND

pad of the ISL6566 to the ground plane with multiple vias is

recommended. This heat spreading allows the part to achieve

its full thermal potential. It is also recommended that the

controller be placed in a direct path of airflow if possible to help

thermally manage the part.

Suppressing MOSFET Gate Leakage

With VCC at ground potential, UGATE is high impedance. In

this state, any stray leakage has the potential to deliver charge

to the gate of the upper MOSFET. If UGATE receives sufficient

charge to bias the device on, a low impedance path will be

connected between the upper MOSFET drain and PHASE. If

this occurs and the input power supply is present and active,

the system could see potentially damaging current. 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.

ISL6566 Datasheet(PDF) 27 Page - Renesas Technology Corp