Analog Output - Cirrus Logic CS42L42 Manual

4.4 Analog Output

This section describes the headphone (HP) outputs. The CS42L42 provides an analog output that is fed from the mixer.
Fig. 4-7 shows the general flow of the analog outputs.
Left
Invert
DACx_INV p. 154
Invert
Right
The output path is sourced directly from the mixer output. The playback path uses advanced analog and digital
signal-processing techniques to adapt to the input signal content and enhance dynamic range and power consumption of the
playback path. The HP output must be muted before changing the state of
maximum HPOUT output voltage. See
Fig. 4-8 shows analog output flow details. Power to DACs is controlled by the related output drivers' PDN bits.
See
on DAC source selection.
Fig. 4-9 is an op-amp–level schematic for the analog output flow.
DACx–
DACx+
4.4.1 Pseudodifferential Outputs
The analog output amplifiers use a pseudodifferential output topology that allows the amplifier to monitor the ground
potential at the load through the reference pins (HSx_REF, RING_SENSE). Minimize the impedance from the CS42L42
reference pin to the load ground (typically the connector ground). Impedance in this path affects analog output attenuation
as well as the common-mode rejection of the output amplifier, which affects output offset and step deviation.
DS1083F2
DAC Data Path
Interpolator
DAC_HPF_EN
p. 154
Interpolator
Figure 4-7. Analog-Output Signal Flow
Table 3-13. HP outputs are muted by
Section 4.2 for details
Figure 4-8. Output Path
Figure 4-9. Op-Amp-Level Schematic—Analog Outputs
DACA
HPOUT_LOAD p. 154
FULL_SCALE_VOL p. 155
ANA_MUTE_B p. 155
ANA_MUTE_A p. 155
DACB
FULL_SCALE_VOL
ANA_MUTE_B
DAC Source
...
Select
–
+
CS42L42
4.4 Analog Output
+VCP_FILT
-
HPOUTA
+
–VCP_FILT
HSx_REF
+VCP_FILT
+
HPOUTB
-
–VCP_FILT
(see p. 155), which sets the
and ANA_MUTE_A
..
DACx
HPSENSx
HPOUTx
HSx_REF
(see p. 155).
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