ISL6209 View Datasheet(PDF) - Renesas Electronics

Part Name

Description

Manufacturer

ISL6209

High Voltage Synchronous Rectified Buck MOSFET Driver

Renesas Electronics 

ISL6209

1. Avoid using vias for decoupling components where

possible, especially in the BOOT-to-PHASE path. Little or

no use of vias for VCC and GND is also recommended.

Decoupling loops should be short.

2. All power traces (UGATE, PHASE, LGATE, GND, VCC)

should be short and wide, and avoid using vias. If vias must

be used, two or more vias per layer transition is

recommended.

3. Keep the SOURCE of the upper FET as close as thermally

possible to the DRAIN of the lower FET.

4. Keep the connection in between the SOURCE of lower FET

and power ground wide and short.

5. Input capacitors should be placed as close to the DRAIN of

the upper FET and the SOURCE of the lower FET as

thermally possible.

NOTE: Refer to Intersil Tech Brief TB447 for more information.

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.

FN9132 Rev.2.00

Mar 23, 2007

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