Cirrus Logic CS4361 - Manual (Page 17)

17
CS4361
Confidential Draft
9/30/11
4.9 Mute Control
The MUTEC pin is intended to be used as control for an external mute circuit in order to add off-chip mute
capability.
This pin becomes active under the following conditions:
1. During power-up initialization
2. Upon reset
3. If the MCLK to LRCK ratio is incorrect
4. Upon receipt of 512 consecutive samples of zero
5. During power-down
The MUTEC pin will only go active on static zero data only if all 6 channels satisfy the 512 sample require-
ment. If any channel receives non-zero data, the mute pin will return low (inactive).
Use of the mute control function is not mandatory but is recommended for designs requiring the absolute
minimum in extraneous clicks and pops. Also, use of the mute control function can enable the system de-
signer to achieve idle channel noise and signal-to-noise ratios that are only limited by the external mute cir-
cuit. The MUTEC pin is an active-high CMOS driver. See
Figure 13 below for a suggested active-high mute
circuit.
470

Audio
Out
2 k

10 k

-V
+V
A
MMUN2111LT1
AOUT
MUTEC
CS4361
AC
Couple
47 k  10 k 
Filter
Cap
MMUN2211LT1
(if available)
6
6
(Low R
on
)
Figure 13. Suggested Active-Low Mute Circuit