CS4297 datasheet(13/46 Pages) CIRRUS

13 / 46 page

DS242F5

CS4297

CrystalClear™ SoundFusion™ Audio Codec ’97

volume level. All analog volume controls, except

PC_BEEP, implement controlled volume steps at

nominally 1.5 dB per step. PC_BEEP uses 3 dB

steps. The analog inputs allow a mixing range of

+12 dB of signal gain to -34.5 dB of signal attenu-

ation. The analog output volume controls allow

from 0 dB to -94.5 dB of attenuation. The

PC_BEEP input volume control allows from 0 dB

to -45 dB of attenuation.

AC’97 IMPLEMENTATION

The CS4297 implements an AC’97 compliant de-

sign as defined in the Intel Audio Codec 97 Speci-

fication Version 1.03. Due to certain design trade-

offs and implementation decisions, the CS4297 dif-

fers from the AC’97 Specification in a a few minor

ways. The following list captures the specification

deviations and the implementation decisions made

to resolve ambiguities.

1. The rising edge of RESET# must occur at least

1.5 ms after the digital power supply DVdd reaches

90% of maximum value.

2. The digital input voltage threshold levels are

specified as percentages of the Vdd digital power

supply and are TTL level compatible. Min Vih =

0.4 x Vdd, Max Vil = 0.16 x Vdd.

3. The delay between setting the PR4 bit to power-

ing down the AC-Link interface is implemented as

16.24

µs.

Figure 1. Mixer Diagram

CS4297 数据表(PDF) 13 Page - Cirrus Logic