CS42448 Datasheet, PDF (31/70 Pages) Cirrus Logic – 108 dB, 192 kHz 6-in, 8-out CODEC

5.0 V
VA
AOUTx+
AOUTx-
4.125 V
2.5 V
0.875 V
4.125 V
2.5 V
0.875 V
Full-Scale Differential Output Level =
(AOUTx+) - (AOUTx-) = 6.5 V_PP = 2.3 V_RMS
Figure 13. Full-Scale Output
4.3.6 Digital Volume Control
Each DAC’s output level is controlled via the Volume Control registers operating over the range
of 0 to -127.5 dB attenuation with 0.5 dB resolution. See “AOUTX Volume Control (addresses
08h- 0Fh)” on page 52. Volume control changes are programmable to ramp in increments of
0.125 dB at the rate controlled by the SZC[1:0] bits in the Digital Volume Control register. See
“Transition Control (address 06h)” on page 50.
Each output can be independently muted via mute control bits in the register “DAC Channel
Mute (address 07h)” on page 52. When enabled, each AOUTx_MUTE bit attenuates the corre-
sponding DAC to its maximum value (-127.5 dB). When the AOUTx_MUTE bit is disabled, the
corresponding DAC returns to the attenuation level set in the Volume Control register. The at-
tenuation is ramped up and down at the rate specified by the SZC[1:0] bits.
4.3.7 De-Emphasis Filter
The CS42448 includes on-chip digital de-emphasis optimized for a sample rate of 44.1 kHz. The
filter response is shown in Figure 14. The de-emphasis feature is included to accommodate au-
dio recordings that utilize 50/15 µs pre-emphasis equalization as a means of noise reduction.
De-emphasis is only available in Single Speed Mode. Please see “DAC De-Emphasis Control
(DAC_DEM)” on page 49 for de-emphasis control.
Gain
dB
T1=50 µs
0dB
-10dB
T2 = 15 µs
F1
3.183 kHz
F2 Frequency
10.61 kHz
Figure 14. De-Emphasis Curve
DS648PP2
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