dac3555a Micronas, dac3555a Datasheet - Page 7

• Manufacturer Part Number: dac3555a
• Description: Stereo Audio Dac
• Manufacturer: Micronas

PRELIMINARY DATA SHEET
2.2. Interpolation Filter
The interpolation filter increases the sampling rate by a
factor of 8. The characteristic for fs
shown in Fig. 2–1.
-0.02
-0.04
-0.06
-0.08
-0.12
-0.14
Fig. 2–1: 1 8 Interpolation filter; frequency range:
2.3. Variable Sample and Hold
The advantage of this system is that even at low sam-
ple frequencies the out-of-band noise is not scaled
down to audible frequencies.
2.4. 3rd-order Noise Shaper and Multibit DAC
The 3rd-order noise shaper converts the oversampled
audio signal into a 5-bit noise-shaping signal at a high
sampling rate. This technique results in extremely low
quantization noise in the audio band.
2.5. Analog Low-pass
The analog low-pass is a first order filter with a cut-off
frequency of approximately 1.4 MHz which removes
the high-frequency components of the noise-shaping
signal.
Micronas
-0.1
dB
0
0
0...22 kHz
5000
10000
15000
audio
= 48 kHz is
20000
f/Hz
2.6. Input Select and Mixing Matrix
This block is used to switch between or mix the auxil-
iary inputs and the signals coming from the DAC. A
switch matrix allows to select between mono and ste-
reo mode as shown in Fig. 2–1.
Fig. 2–1: Switch matrix
Mono mode is realized by adding left and right chan-
nel.
2.7. Postfilter Op Amps, Deemphasis Op Amps,
This block contains the active components for the ana-
log postfilters and the deemphasis network. The
op amps and all I/O-pins for this block are shown in
Fig. 2–2.
$8;/
$8;5
$8;/
$8;5
and Line-Out
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DAC 3555A
)287/
)2875
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