PM6680ATR datasheet(44/48 Pages) STMICROELECTRONICS

44 / 48 page

Design guidelines

PM6680A

44/48

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As general rule, make the high side and low side drivers traces wide and short. The

high side driver is powered by the bootstrap circuit. It's very important to place

capacitor CBOOT and diode DBOOT as near as possible to the HGATE pin (for

example on the layer opposite to the device). Route HGATE and PHASE traces as near

as possible in order to minimize the area between them.

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The Low side gate driver is powered by the 5 V linear regulator output. Placing PGND

and LGATE pins near the low side MOSFETs reduces the length of the traces and the

crosstalk noise between the two sections.

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The linear regulator output LDO5 is referred to SGND as long as the reference voltage

Vref. Place their output filtering capacitors as near as possible to the device.

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Place input filtering capacitors near VCC and VIN pins.

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It would be better if the feedback networks connected to COMP, FB and OUT pins are

"referred" to SGND in the same point as reference voltage Vref. To avoid capacitive

coupling place these traces as far as possible from the gate drivers and phase

(switching) paths.

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Place the current sense traces on the bottom side. Using It is recommended to use a

dedicated connection between the switching node and the current limit resistor

RCSENSE.

PM6680ATR Datasheet(PDF) 44 Page - STMicroelectronics