TDA1386T Philips Semiconductors, TDA1386T Datasheet - Page 11

• Manufacturer Part Number: TDA1386T
• Description: Noise shaping filter DAC
• Manufacturer: Philips Semiconductors

Philips Semiconductors
There are two recommended application situations within
the microcontroller mode:
De-emphasis
A digital de-emphasis is implemented in the TDA1386T.
By selecting the DEEM bit at register D4 (microcontroller
application mode) or activating the APP0 pin
(pseudo-static application mode), de-emphasis can be
applied by means of an IIR filter. De-emphasis is
synchronized to prevent operation in the middle of a word.
1998 Jan 06
The customer wants to use the microcontroller interface
without the volume setting facility. In this event the
operation is as follows:
– Mute ON; by sending the MUSB command
– Mute OFF; by sending the FS command
– Attenuation ON; by sending the ATSB command
– Attenuation OFF; by sending the FS command.
It is possible to switch from ‘Attenuation ON’ to
‘Mute ON’ but not vice-versa.
Incorporating the volume control feature operates as
follows:
– Mute ON; by sending the MUSB command the
– Mute OFF; by sending succeeding INCR commands
– Attenuation ON; by sending succeeding DECR
– Attenuation OFF; by sending the succeeding INCR
– Volume UP; by sending successive INCR
– Volume DOWN; by sending successive DECR
Noise shaping filter DAC
microcontroller has to store the previous volume
setting.
until the previous volume is reached.
commands until a relative downstep of 12 dB is
reached. The microcontroller has to store the
previous volume.
commands until the previous volume is reached.
commands.
commands.
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Double-speed mode
The double-speed mode is controlled by the DSMB bit at
register D6 (microcontroller application mode) or by
activating the APP1 pin (pseudo static application mode).
When the control bit is active LOW the device operates in
the double-speed mode.
Oversampling filter and noise shaper
The digital filter is a four times oversampling filter. It
consists of two sections which each increase the sample
rate by 2. The noise-shaper operates on 4f
the in-band noise density.
DAC and operational amplifiers
In this noise shaping DAC a special data code and
bidirectional current sources are used in order to achieve
true low-noise performance. The special data code
guarantees that only small values of current flow to the
output during small signal passages while larger positive
or negative values are generated using the bidirectional
current sources. The noise shaping DAC uses the
continuous calibration conversion technique. The DAC
currents are repeatedly generated from one single
reference current.
The operational amplifiers and the internal conversion
resistors R
an output voltage available at VOL and VOR. Connecting
an external capacitor between FILTCL and VOL, FILTCR
and VOR respectively provides the required first-order
post filtering.
CONV1
and R
CONV2
convert the DAC current to
Product specification
TDA1386T
s
and reduces