TDA7501 datasheet(5/18 Pages) STMICROELECTRONICS

5 / 18 page

DESCRIPTION OF THE INPUT PART

On the input side, the DSPLD (see figure 1) con-

nects the external audio- and tuner-signals to the

four AD-converters of the Digital Carradio Signal

Processor TDA7500. The audio signals are ad-

justed by the input gain stage to the internal refer-

ence signal with 2V rms referred to 4.15V (=V33

Ã 1.2575). The following CODEC-interface at-

tenuates the 2Vrms to 0.8Vrms referred to the

CODEC’s reference voltage of 1.65V which al-

lows a DC-coupling to the TDA7500.

Figure 1. Input part.

Input Stages

The decive offers several input stages for the dif-

ferent signals which have to be handled by the

system. A quasi differential input (see figure 2)

can be used for (external) CD-changer. The two

mono differential inputs allow the connection of

Phone and Navigation (see figure 3) or it could be

used as fully differential stereo input. Additionally

a single-ended stereo input is available for Cas-

sette applications. The lower part of the input

section is dedicated to the tuner signals. Another

quasi differential input (see figure 4) is used to

connect AM and FM referred to the tuner refer-

ence (Tuner-). This concept supports also double

tuner systems. Also two seperate level inputs are

present which are followed by level-shifters to al-

low the use of the TDA7500’s ADCs. For AM

noise blanking an envelope-detector driven by

the AM-IF is also available.

TDA7501

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