Digital Logic

and

Audio

Processor

Digital Power

+V

DGND

D

Digital Section

Analog Section

Return Path for Digital Signals

Analog Power

+VS

AGND

–VS

+5VA

Digital

Ground

Analog

Ground

Output

Circuits

PCM1754

AGND

VCC

DGND

29

PCM1753, PCM1754, PCM1755

www.ti.com

SLES092E – APRIL 2003 – REVISED JULY 2019

Product Folder Links: PCM1753 PCM1754 PCM1755

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Copyright © 2003–2019, Texas Instruments Incorporated

10 Power Supply Recommendations

The PCM175x devices are designed to operate from a 4.5-V to 5.5-V power supply. Ensure that the power

supply is clean and use high-quality decoupling capacitors to reduce noise. The bulk capacitances can be from

either tantalum or aluminum capacitors.

Separate power supplies are recommended for the digital and analog sections of the board. This prevents the

switching noise present on the digital supply from contaminating the analog power supply and degrading the

dynamic performance of the PCM175x devices. In cases where a common 5-V supply must be used for the

analog and digital sections, an inductance (RF choke, ferrite bead) should be placed between the analog and

digital 5-V supply connections to avoid coupling of the digital switching noise into the analog circuitry. Figure 39

shows the recommended approach for single-supply applications.

11 Layout

11.1 Layout Guidelines

Figure 38 shows a typical PCB floor plan for the PCM175x devices. A ground plane is recommended, with the

analog and digital sections being isolated from one another using a split or cut in the circuit board. The PCM175x

should be oriented with the digital I/O pins facing the ground plane split/cut to allow for short, direct connections

to the digital audio interface and control signals originating from the digital section of the board.

Separate power supplies are recommended for the digital and analog sections of the board. This prevents the

switching noise present on the digital supply from contaminating the analog power supply and degrading the

dynamic performance of the PCM175x. In cases where a common 5-V supply must be used for the analog and

digital sections, an inductance (RF choke, ferrite bead) should be placed between the analog and digital 5-V

supply connections to avoid coupling of the digital switching noise into the analog circuitry. Figure 39 shows the

recommended approach for single-supply applications.

11.2 Layout Example

Figure 38. Recommended PCB Layout