Cirrus Logic CS4384 - Manual (Page 28)

28 DS620F1
CS4384
4.11 The MUTEC Outputs
The MUTEC1 and MUTEC234 pins have an auto-polarity detect feature. The MUTEC output pins are high
impedance at the time of reset. The external mute circuitry needs to be self biased into an active state in
order to be muted during reset. Upon release of reset, the CS4384 will detect the status of the MUTEC pins
(high or low) and will then select that state as the polarity to drive when the mutes become active. The ex-
ternal-bias voltage level that the MUTEC pins see at the time of release of reset must meet the “MUTEC
auto detect input high/low voltage” specs as outlined in the Digital Characteristics section.
Figure 25 shows a single example of both an active high and an active low mute drive circuit. In these de-
signs, the pull-up and pull-down resistors have been especially chosen to meet the input high/low threshold
when used with the MMUN2111 and MMUN2211 internal bias resistances of 10 k
Ω.
Use of the Mute Control function is not mandatory but recommended for designs requiring the absolute min-
imum in extraneous clicks and pops. Also, use of the Mute Control function can enable the system designer
to achieve idle channel noise/signal-to-noise ratios which are only limited by the external mute circuit.
AOUT
Full-Scale Output Level= AOUT= 3.35 Vpp
4.175 V
2.5 V
0.825 V
Figure 23. Full-Scale Output
Figure 24. Recommended Output Filter