HMP9701 Просмотр технического описания (PDF) - Intersil

Номер в каталоге

Компоненты Описание

производитель

HMP9701

AC’97 Audio Codec

Intersil 

Functional Block Diagram

HMP9701

HMP9701 AC’97 AUDIO CODEC

MIC1

MIC2

LINE_IN

CD

VIDEO

AUX

PHONE

GAIN

0dB / 20dB

MONO_OUT

MONO

VOL

G

A

M

LINE_OUT

MASTER

VOL

∑

PC_BEEP

GAM

∑

GGGGG

AAAAA

MMMMM

∑

∑

RECORD

GAIN

Σ∆ A/D

Σ∆ A/D

Σ∆ A/D

AC’97

CONTROL/CONFIGURATION

(64 REGISTERS)

GAM

Σ∆ D/A

Σ∆ D/A

SYNC

BIT_CLK

SDATA_OUT

SDATA_IN

RESET

STEREO SIGNAL PATH

MONO SIGNAL PATH

Functional Description

The HMP9701 is a full-duplex stereo audio codec compliant to

the AC’97 Codec specification. This component is designed for

use in multimedia and business personal computers. The

codec includes full duplex stereo converters, a mic pass

through ADC, complete on-chip anti-alias filtering, and a 5

channel analog mixer with programmable gain and attenuation.

Analog Inputs

The HMP9701 has 4 stereo inputs (LINE_IN, CD, VIDEO, and

AUX), two microphone level inputs (MIC1 and MIC2), and one

mono line level input (PHONE). A multiplexer is provided to

independently select the right and left record sources from the

analog inputs listed above. In addition, the output stereo mix

(LINE_OUT) or its mono equivalent may also be selected as a

record source. A gain block is available to amplify the MIC

inputs by 20dB to compensate for the difference between line

levels and typical condenser microphone levels.

Besides being fed to the Record Select Mux, all analog

inputs can be mixed (see Analog Mixer) with the stereo out-

put from the Playback DACs. Note: all analog inputs except

PHONE and PC_BEEP can be output on MONO_OUT.

There is a dedicated analog input, PC_BEEP, for the

standard “Beep” signal provided on most PC/Compatible

computers for power on self test and boot audio status

indication. This input is mixed into each channel of the

stereo line outputs.

Record ADCs

The HMP9701 provides 3 Σ∆ ADCs to record one dedicated

microphone input and 2 user selectable analog inputs. The

user selectable analog inputs are routed to the stereo ADCs

via an programmable Input Multiplexer. The multiplexer is

programmed to select the 2 record channels via the Record

Select register (1Ah).

Each of the record channels pass through a programmable

gain block before each ADC. The record gain for each chan-

nel is set individually and ranges from 0dB to 22.5dB in

1.5dB increments (see Record Gain Registers 1Ch and

1Eh). The gain block can also be used to mute each chan-

nel. Note: an additional gain block provides 20dB of gain on

the MIC channel if activated (see MIC Volume register 0Eh).

The HMP9701 uses oversampling Σ∆ ADCs which only

require a single pole passive filter for anti-alias filtering. The

filter for the left, right and MIC channels is realized by placing

a 1nF capacitor between the AFILT1, AFILT2, and AFILT3

pins and analog ground respectively.

Playback DACs

The HMP9701 uses oversampling single bit Σ∆ DACs to con-

vert the stereo playback sample to an analog line level output.

The output of the DACs pass through internal reconstruction

filters that do not require any external components.

2

Share Link: