PCM1770 Datasheet, PDF (23/29 Pages) Texas Instruments – LOW VOLTAGE AND POWER STEREO AUDIO DIGITAL TO ANALOG CONVER WITH HEADPHONE AMPLIFER

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PCM1770
PCM1771
SLES011C – SEPTEMBER 2001 – REVISED MAY 2004
ATL[5:0]: Digital Attenuation Level Setting for Headphone Output, H_OUTL
Default value: 11 1111b
Headphone output, H_OUTL includes a digital attenuation function. The attenuation level can be set from 0 dB to
–62 dB, in 1.0-dB steps. Changes in attenuator levels are made by incrementing or decrementing by one step
(1.0 dB) for every 8/f_S time internal until the programmed attenuator setting is reached. Alternatively, the
attenuation level may be set to infinite attenuation (or mute).
The following table shows the attenuation levels for various settings:
ATL[5:0]
11 1111b
11 1110b
11 1101b
L
00 0010b
00 0001b
00 0000b
ATTENUATION LEVEL SETTING
0 dB, no attenuation (default)
–1.0 dB
–2.0 dB
L
–61.0 dB
–62.0 dB
Mute
Register 02
B15 B14 B13 B12 B11 B10 B9 B8 B7
0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 RSV
B6 B5 B4 B3 B2 B1 B0
RSV ATR5 ATR4 ATR3 ATR2 ATR1 ATR0
IDX[6:0]: 000 0010b
ATR[5:0]: Digital Attenuation Level Setting for Headphone Output, H_OUTR
Default Value: 11 1111b
Headphone output, H_OUTR includes a digital attenuation function. The attenuation level can be set from 0 dB to
–62 dB, in 1-dB steps. Changes in attenuator levels are made by incrementing or decrementing by one step (1.0
dB) for every 8/f_S time internal until the programmed attenuator setting in reached. Alternatively, the attenuation
level can be set to infinite attenuation (or mute).
To set the attenuation levels for ATR[5:0], see the table for ATL[5:0], register 01.
B15 B14 B13 B12 B11 B10 B9 B8 B7
B6
B5 B4 B3 B2
B1
B0
Register 03 0 IDX6 IDX5 IDX4 IDX3 IDX2 IDX1 IDX0 OVER RSV RINV AMIX DEM FMT2 FMT1 FMT0
IDX[6:0]: 000 0011b
OVER: Over Sampling Control
Default Value: 0
OVER = 0
OVER = 1
128 f_S oversampling
192 f_S, 256 f_S, 384 f_S oversampling
The OVER bit controls the oversampling rate of the ∆-Σ D/A converters. When it operates at a low sampling rate,
less than 24 kHz, this function is recommended.
RINV: Polarity Control for Headphone Output, H_OUTR
Default Value: 0
RINV = 0
RINV = 1
Not inverted
Inverted output
The RINV bits allow the user to control the polarity of the headphone output, H_OUTR. This function can be used to
connect the monaural speaker with BTL connection method. This bit is recommended to be 0 during the
power-up/-down sequence for minimizing audible pop noise.
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