TDA9875A Philips Semiconductors, TDA9875A Datasheet - Page 19

• Manufacturer Part Number: TDA9875A
• Description: Digital TV Sound Processor DTVSP
• Manufacturer: Philips Semiconductors

Philips Semiconductors
6.3.5
The line output can provide an unprocessed copy of the
audio signal in the loudspeaker channels. This can be
either an external signal that comes from the dual audio
ADC, or a signal from an internal digital audio source that
comes from the dual audio DAC. The line output employs
amplifiers with two gain settings. The 3 dB position is
needed to compensate for the attenuation at the SCART
inputs, while the 0 dB position is needed, for example, for
non-attenuated external or internal digital signals
(see Section 6.3.4).
6.3.6
Signals from any audio source can be applied to the
loudspeaker and to the headphone output channels via the
digital crossbar switch and the DSP.
6.3.7
The TDA9875A contains three dual audio DACs, one for
the connection from the DSP to the analog crossbar switch
section and two for the loudspeaker and headphone
outputs. Each of the three dual low-noise high-dynamic
range DACs consists of two 15-bit DACs with current
outputs, followed by a buffer operational amplifier.
The audio DACs operate with four-fold oversampling and
noise shaping.
1999 Dec 20
Digital TV Sound Processor (DTVSP)
L
L
(A
D
INE OUTPUT
OUDSPEAKER
UAL AUDIO
UXILIARY
)
OUTPUTS
DAC
(M
AIN
)
AND HEADPHONE
19
6.3.8
There is one dual audio ADC in the TDA9875A for the
connection of the analog crossbar switch section to the
DSP. The dual audio ADC consists of two bitstream
third-order sigma-delta audio ADCs and a high-order
decimation filter.
6.3.9
The standby mode, selected by setting bit STDBY to
logic 1 (see Section 10.3.2) disables most functions and
reduces power dissipation. The analog crossbar switch
and the SCART section remain operational and can be
controlled by the I
signals from SCART-to-SCART.
Unused internal registers may lose their information in the
standby mode. Therefore, the device needs to be
initialized on returning to the normal operating mode. This
can be accomplished in the same way as after a Power-on
reset.
6.3.10
The different supply grounds V
via the substrate. It is recommended to connect all ground
pins by means of a copper plane close to the pins.
D
S
S
TANDBY MODE
UPPLY GROUND
UAL AUDIO
2
C-bus to support copying of analog
ADC
SS
are internally connected
Product specification
TDA9875A