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TPA3221

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SLASEE9 – JUNE 2017

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Copyright © 2017, Texas Instruments Incorporated

Power Supplies (continued)

11.1.4 BST Supply

TPA3221 has built-in bootstrap supply for each half bridge gate drive to supply the high side MOSFETs, only

requiring a single capacitor per half bridge. The capacitors are connected to each half bridge oputput, and are

arged by the GVDD supply via an internal diode while the PWM outputs are in low state. The high side gate drive

is supplied by the voltage across the BST capacitor while the output PWM is high. It is recomemnded to place

the BST capacitors close to the TPA3221 device, and to keep PCB routing traces at minimum length.

12 Layout

12.1 Layout Guidelines

•

Use an unbroken ground plane to have good low impedance and inductance return path to the power supply

for power and audio signals.

•

Maintain a contiguous ground plane from the ground pins to the PCB area surrounding the device for as

many of the ground pins as possible, since the ground pins are the best conductors of heat in the package.

•

PCB layout, audio performance and EMI are linked closely together.

•

Routing the audio input should be kept short and together with the accompanied audio source ground.

•

The small bypass capacitors on the PVDD lines of the DUT be placed as close the PVDD pins as possible.

•

A local ground area underneath the device is important to keep solid to minimize ground bounce.

•

Orient the passive component so that the narrow end of the passive component is facing the TPA3221

device, unless the area between two pads of a passive component is large enough to allow copper to flow in

between the two pads.

•

Avoid placing other heat producing components or structures near the TPA3221 device.

•

Avoid cutting off the flow of heat from the TPA3221 device to the surrounding ground areas with traces or via

strings, especially on output side of device.

Netlist for this printed circuit board is generated from the schematic in Figure 23.