CS4811 datasheet(12/24 Pages) CIRRUS

12 / 24 page

CS4811

DS486PP2

3. FUNCTIONAL DESCRIPTION

3.1

Overview

The CS4811 is a complete audio subsystem on a

chip, integrating a proprietary 24-bit audio process-

ing engine with large on chip RAM memories and

a single channel 24-bit audio codec.

The delta-sigma ADC includes linear phase digital

anti-aliasing filters and only requires a single-pole

external passive filter.

The sigma-delta DAC includes a switched-capaci-

tor anti-image filter and requires an external 2nd or

3rd order active filter that can be easily integrated

into the output differential-to-single-ended con-

verter circuit.

The serial control port is designed to accommodate

I2C® or SPI interfaces for stand-alone operation

with an external non-volatile memory.

3.2

Analog Inputs

3.2.1

Line Level Inputs

AIN+ and AIN- are the differential line level ana-

log inputs (See Figure 3). These pins are internally

biased to the CMOUT voltage of 2.3 V. A DC

blocking capacitor placed in series with the input

pins allows signals centered around 0 V to be input

to the CS4811. Figure 3 shows operation with a

single-ended input source. This source may be sup-

plied to either the positive or negative input as long

as the unused input is connected to ground through

capacitors as shown. When operated with single-

ended inputs, distortion will increase at input levels

higher than -1 dB Full Scale. If better performance

is required, a single-ended-to-differential convert-

er, shown in Figure 6, may be used. This circuit

provides unity gain, DC blocking on the input and

anti-alias filtering.

The OVL output pin asserts when the analog input

is out-of-range.

3.2.2

Digital High Pass Filter

In DC coupled systems, a small DC offset may ex-

ist between the input circuitry and the A/D con-

verters. The CS4811 includes a high pass filter

after the decimator to remove these DC compo-

nents. The high pass filter response, given in High

Pass Filter Characteristics, scales linearly with

sample rate. Thus, the -3 dB frequency at a

44.1 kHz sample rate will be equal to 44.1/48 times

that at a sample rate of 48 kHz.

10 k

4.7 k

AIN -

10 µ F

AIN +

2.2 nf

150

10 k

input signal

(2 Vrms max)

+5 V

CMOUT

from

CS4811

0.1 µF

10 µf

GND

Buffered

CMOUT

Figure 6. Optional Line Input Buffer

CS4811 датащи(PDF) 12 Page - Cirrus Logic

CS4811 датащи(HTML) 12 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

датащи скачать

ссылки URL