Datasheet

2 .2 μF

1 .0 μF

BP18

DGND

V33D

UCD3138

SLUSAP2F –MARCH 2012 –REVISED NOVEMBER 2013

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5 IC Grounding and Layout Recommendations

• Two grounds are recommended: AGND (analog) and DGND (digital).

– AGND plane should be on a different layer than DGND, and right under the UCD3138 device.

– UCD3138 power pad should be tied to AGND plane by at least 4 vias

– AGND plane should be just large enough to connect to all required components.

– Power ground (PGND) can be independent or combined with DGND

– The power pad of the driver IC should be tied to DGND

• Both 3.3VD and 3.3VA should have a local 4.7µF capacitor placed as close as possible to the device

pins

• BPCAP decoupling (2.2 µF typically) MUST be connected to DGND

• All analog signal filter capacitors should be tied to AGND

– If the gate driver device, such as UCD27524 or UCD27511/7 driver is used, the filter capacitor for

the current sensing pin can be tied to DGND for easy layout

• All digital signals, such as GPIO, PMBus and PWM are referenced to DGND.

• The RESET pin capacitor (0.1µF) should be connected to either DGND or AGND locally. A 10kΩ pull-

up resistor to 3.3V is recommended.

• All filter and decoupling capacitors should be placed close to UCD3138 as possible

– Resistor placement is less critical and can be moved a little further away

• The DGND and AGND net-short resistor MUST be placed right between one UCD3138’s DGND pin

and one AGND pin. Ground connections to the net short element should be made by a large via (or

multiple paralleled vias) for each terminal of the net-short element.

• If a gate driver device such as UCC27524 or UCC27511/7 is on the control card and there is a PGND

connection, a net-short resistor should be tied to the DGND plane and PGND plane by multiple vias. In

addition the net-short element should be close to the driver IC.

• Configure all unused GPIO as inputs and connect them to ground.

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Product Folder Links: UCD3138