FEATURES

• AC '97 Rev 2.1 Compliant

• High Quality Sample Rate Conversion from 4

kHz to 48 kHz in 1 Hz Increments

• Multiple Codec Support

• Texas Instruments' 3D Sound Stereo

Enhancement Circuitry

• Advanced Power Management Support

• Digital 3.3V and 5V Supply Options

• Extended Temperature: −40°C ≤ TA ≤ 85°C

APPLICATIONS

• Desktop PC Audio Systems on PCI Cards,

AMR Cards, or with Motherboard Chips Sets

Featuring AC Link

• Portable PC Systems as on MDC Cards, or

with a Chipset or Accelerator Featuring AC

Link

• General and Multi-channel Audio Frequency

Systems

• Automotive Telematics

KEY SPECIFICATIONS

• Analog Mixer Dynamic Range 97 dB (typ)

• DAC Dynamic Range 89 dB (typ)

• ADC Dynamic Range 90 dB (typ)

DESCRIPTION

The LM4546B is an audio codec for PC systems

which is fully PC99 compliant and performs the

analog intensive functions of the AC '97 Rev 2.1

architecture. Using 18-bit Sigma-Delta ADCs and

DACs, the LM4546B provides 90 dB of Dynamic

Range.

The LM4546B was designed specifically to provide a

high quality audio path and provide all analog

functionality in a PC audio system. It features full

duplex stereo ADCs and DACs and analog mixers

with access to 2 stereo and 2 mono inputs. Each

mixer input has separate gain, attenuation and mute

control and the mixers drive 1 mono and 1 stereo

output, each with attenuation and mute control. The

LM4546B supports Texas Instruments' 3D Sound

stereo enhancement and a comprehensive sample

rate conversion capability. The sample rate for the

ADCs and DACs can be programmed separately with

a resolution of 1 Hz to convert any rate in the range 4

kHz – 48 kHz. Sample timing from the ADCs and

sample request timing for the DACs are completely

deterministic to ease task scheduling and application

software development. These features together with

an extended temperature range also make the

LM4546B suitable for non-PC codec applications.

The LM4546B features the ability to connect several

codecs together using the Extended AC Link

configuration of one dedicated serial data signal to

the Controller per codec. LM4546B systems support

up to 8 simultaneous channels of streaming data on

Input Frames (Codec to Controller) while Output

Frames (Controller to Codec) carry 2 streams to

multiple codecs. The LM4546B may also be used in

systems with the Texas Instruments LM4550 to

support up to 6 simultaneous channels of streaming

data on Output Frames.

The AC '97 architecture separates the analog and

digital functions of the PC audio system allowing both

for system design flexibility and increased

performance.