PCM1753
PCM1754
PCM1755
SLES092A – OCTOBER 2003 – REVISED AUGUST 2004
www.ti.com
Register Definitions
B15
B14
B13
B12
B11
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
Register 16
Register 17
0
IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT17 AT16 AT15 AT14 AT13 AT12 AT11 AT10
B15
B14
B13
B12
B11
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
0
IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 AT27 AT26 AT25 AT24 AT23 AT22 AT21 AT20
ATx[7:0]: Digital Attenuation Level Setting
Where x = 1 or 2, corresponding to the DAC output V
Default value: 1111 1111b
L (x = 1) and V
OUT
R (x = 2).
OUT
Each DAC channel (V
L and V
OUT
R) includes a digital attenuation function. The attenuation level can be
OUT
set from 0 dB to –63 dB in 0.5-dB steps. Changes in attenuator levels are made by incrementing or
decrementing one step (0.5 dB) for every 8/f time internal until the programmed attenuator setting is reached.
S
Alternatively, the attenuation level can be set to infinite attenuation (or mute).
The attenuation data for each channel can be set individually. The attenuation level is set using the following
formula:
Attenuation level (dB) = 0.5 × (ATx[7:0]
– 255)
DEC
where ATx[7:0]
= 0 through 255.
DEC
For ATx[7:0]
= 0 through 128, attenuation is set to infinite attenuation.
DEC
The following table shows the attenuation levels for various settings:
ATx[7:0]
1111 1111b
1111 1110b
1111 1101b
L
DECIMAL VALUE
ATTENUATION LEVEL SETTING
255
254
253
L
0 dB, No Attenuation. (default)
–0.5 dB
–1.0 dB
L
1000 0011b
1000 0010b
1000 0001b
1000 0000b
L
131
130
129
128
L
–62.0 dB
–62.5 dB
–63.0 dB
Mute
L
0000 0000
0
Mute
B
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 SRST OVER RSV
RSV
RSV
RSV MUT2 MUT1
MUTx: Soft Mute Control
where x = 1 or 2, corresponding to the DAC outputs VOUT L (x = 1) and VOUTR (x = 2).
Default value: 0
MUTx = 0
MUTx = 1
Mute disabled (default)
Mute enabled
The mute bits, MUT1 and MUT2, are used to enable or disable the soft mute function for the corresponding
DAC outputs, V L and V R. The soft mute function is incorporated into the digital attenuators. When mute
OUT
OUT
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 infinite attenuation,
one attenuator step (0.5 dB) for every 8/f seconds. This provides pop-free muting of the DAC output.
S
20
BB [ BURR-BROWN CORPORATION ]
