CS8412 datasheet(13/36 Pages) CIRRUS

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CS4327

DS190F1

Analog Output and Filtering

The CS4327 contains an on-chip buffer amplifier

producing single-ended outputs. Each output will

produce a nominal 2.83 Vpp (1 Vrms) output with

a 2.3 volt common mode for a full scale digital in-

put.

The CS4327 filter is a linear phase design and does

not include phase or amplitude compensation for

an external filter. Therefore, the DAC system phase

and amplitude response will be dependent on the

external analog circuitry. The second-order low-

pass filter with a -3 dB frequency of 50 kHz shown

in Figure 10 will give good results in most applica-

tions. The design of this filter is discussed in AN55,

the Crystal Applications Note "Design Notes for a

2-pole Filter." Figure 11 displays the the output

spectrum of the CS4327. Figure 12 displays the

output spectrum following the 2-pole filter. Notice

the attenuation beyond 50 kHz.

150 pF

3.4k

10k

100 pF

20k

Figure 10. 2-pole Butterworth Fillter

Figure 11. CS4327 Output Spectrum

Fs = 48 kHz

Figure 12. 2-pole Filtered Output Spectrum

Fs = 48 kHz

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