2 serial audio interface, 3 digital interface, 4 analog connections – Cirrus Logic CS5344 User Manual
Page 14: Sour, Figure 6 on
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DS687F4
CS5343/4
Draft
2/1/11
4.2
Serial Audio Interface
The CS5343 output is serial data in I²S audio format and the CS5344 output is serial data in Left-Justified
audio format.
and
show the I²S and Left-Justified data relative to SCLK and LRCK. Additionally,
and
display more information on the required timing for the serial audio interface format. For an
overview of serial audio interface formats, please refer to Cirrus Application Note AN282.
4.3
Digital Interface
VA supplies power to both the analog and digital sections of the ADC, and also powers the serial port. Con-
sequently, the digital interface logic level must equal VA to within the limits specified under
4.4
Analog Connections
The analog modulator samples the input signal at half of the internal master clock rate, or 6.144 MHz when
MCLK = 12.288 MHz. The digital filter will reject signals within the stopband of the filter. However, there is
no rejection for input signals which are multiples of the input sampling frequency (n
6.144 MHz), where
n=0,1,2,... Refer to
which shows the recommended topology of the analog input network. The ex-
ternal shunt capacitor and internal input impedance form a single-pole RC filter to provide the appropriate
filtering of noise at the modulator sampling frequency. Additionally, the 180 pF capacitor acts as a charge
source for the internal sampling circuits. Capacitors of NPO or other high-quality dielectric will produce the
best results while capacitors with a large voltage coefficient (such as general-purpose ceramics) can de-
grade signal linearity.
Figure 4. CS5343 I²S Serial Audio Interface
SDATA
23 22
8
7
23 22
SCLK
LRCK
23 22
6
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
9
9
Left Channel
Right Channel
Figure 5. CS5344 Left-Justified Serial Audio Interface
SDATA
23 22
7
6
23 22
SCLK
LRCK
23 22
5
4
3
2
1
0
8
7
6
5
4
3
2
1
0
8
9
9
Left Channel
Right Channel
Figure 6. CS5343/4 Analog Input Network
CS5343/4
AIN
Input
R1
R2
1 µF
180pF
C0G