8.3 Power Supply Recommendations

The power supply to the CD326x must have a current rating according to the supply voltage, output voltage,

supply current, and output current of the CD326x.

8.4 Layout

8.4.1 Layout Guidelines

The system level performance metrics, including thermal performance, electromagnetic compliance (EMC),

device reliability, and audio performance are all affected by the device and supporting component layout. The

guidance provided in the applications section with regard to device and component selection can be followed by

precise adherence to the layout guidance shown in the Section 8.4.2. This example represents an exemplary

baseline balance of the engineering trade-offs involved with lying out the device. This design can be modified

slightly as needed to meet the needs of a given application. In some applications, for instance, footprint size

can be compromised to improve thermal performance through the use of additional contiguous copper neat the

device. Conversely, EMI performance can be prioritized over thermal performance by routing on internal traces

and incorporating a via picket-fence and additional filtering components. The recommended process is to start

with the guidance shown in the Section 8.4.2 and work with TI field application engineers or through the E2E

community to modify the layout based upon the application specific goals.

• See Figure 8-5 for the recommended layout of the CD326x, which is designed for common external

GND connections. TI recommends placing all components as close as possible to the package pins. The

recommended layout is implemented on the EVM and shown in the EVM user's guide.

• Provide low capacitive paths (with respect to all other nodes) for traces with high dv/dt. Therefore, the input

and output capacitance must be placed as close as possible to the IC pins and parallel wiring over long

distances as well as narrow traces must be avoided. Loops which conduct an alternating current must outline

an area as small as possible, as this area is proportional to the energy radiated

• Use a ground plane with multiple vias for each terminal to create a low-impedance connection to GND for

minimum ground noise.

• A single common GND plane is recommended to avoid a potential voltage difference between signals.

• When placing decoupling capacitors, especially for the VSHUNT pin, place the capacitors as close to the

device as possible. Typically recommended capacitor is 0.1µF.

CD3268A, CD3269A

SCHS463 – MAY 2025

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