PM6681A STMicroelectronics, PM6681A Datasheet - Page 43

• Manufacturer Part Number: PM6681A
• Description: Dual synchronous step down controller with adjustable LDO
• Manufacturer: STMicroelectronics

PM6681A
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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. 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.
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.
Place input filtering capacitors near VCC and VIN pins.
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.
Place the current sense traces on the bottom side. If low side MOSFET R
is enabled, use a dedicated connection between the switching node and the current
limit resistor R
CSENSE.
Layout guidelines
DS(on)
sensing
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