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MUTx – Soft Mute Control

OVER – Oversampling Rate Control

PCM1742

SBAS176A – DECEMBER 2000 – REVISED APRIL 2005

B15

B14

B13

B12

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

REGISTER 18

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV

OVER

RSV

RSV

RSV

RSV

MUT2

MUT1

where x = 1 or 2, corresponding to the DAC output VOUTL (x = 1) and VOUTR (x = 2).

Default value: 0

MUTx = 0

Mute disabled (default)

MUTx = 1

Mute enabled

The mute bits, MUT1 and MUT2, are used to enable or disable the soft mute function for the corresponding DAC

outputs, VOUTL and VOUTR. The soft mute function is incorporated into the digital attenuators. When mute is

disabled (MUTx = 0), the attenuator and DAC operate normally. When mute is enabled by setting MUTx = 1, the

digital attenuator for the corresponding output is decreased from the current setting to the infinite attenuation

setting by one attenuator step (0.5 dB) at a time for every 8/fS period. This provides a pop-free muting of the

DAC output.

By setting MUTx = 0, the attenuator is increased by one step for every 8/fS period to the previously programmed

attenuation level.

Default value: 0

System clock rate = 256 fS, 384 fS, 512 fS, or 768 fS

OVER = 0

64× oversampling (default)

OVER = 1

128× oversampling

System clock rate = 128 fS or 192 fS

OVER = 0

32× oversampling (default)

OVER = 1

64× oversampling

The OVER bit is used to control the oversampling rate of the delta-sigma DACs. The OVER = 1 setting is

recommended when the oversampling rate is 192 kHz (system clock is 128 fS or 192 fS).

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