PCM1793

SLES076A − MARCH 2003 − REVISED JANUARY 2004

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23

VDD

Digital Section

Analog Section

RF Choke or Ferrite Bead

Power Supplies

Common

Ground

Output

Circuits

AGND

VCC

+VS

+5V

−VS

AGND

VDD

DGND

REG

PCM1793

Figure 31. Single-Supply PCB Layout

Bypass and Decoupling Capacitor Requirements

Various-sized decoupling capacitors can be used, with no special tolerances being required. All capacitors must be

located as close as possible to the appropriate pins of the PCM1793 to reduce noise pickup from surrounding circuitry.

Aluminum electrolytic capacitors that are designed for hi-fi audio applications are recommended for larger values,

while metal film or monolithic ceramic capacitors are used for smaller values.

Post-LPF Design

By proper choice of the op amp and resistors used in the post-LPF circuit, excellent performance of the PCM1793

should be achieved. To obtain 0.001% THD+N, 113 dB signal-to-noise-ratio audio performance, the THD+N and input

noise performance of the op amp must be considered. This is because the input noise of the op amp contributes

post-LPF circuit must be connected as closely as possible.

Out-of-band noise level and attenuated sampling spectrum level are much lower than for typical delta-sigma type

DACs due to the combination of a high-performance digital filter and advanced segment DAC architecture. The use

of a second-order or third-order post-LPF is recommended for the post-LPF of the PCM1793. The cutoff frequency

of the post-LPF depends on the application. For example, there are many sampling-rate operations such as