SGS Thomson Microelectronics TDA7402 Datasheet

CARRADIO SIGNAL PROCESSOR

■

3 STEREO INPUTS

■ 3 MONO INPUTS

■

DYNAMIC-COMPRESSION-STAGE FOR CD

■

SOFTSTEP-VOLUME

■

BASS, TREBLE AND LOUDNESS CONTROL

■ VOICE-BAND-FILTER

■

DIRECT MUTE AND SOFTMUTE

■

INTERNAL BEEP

■ FOUR INDEPENDENT SPEAKER-OUTPUTS

■

STEREO SUBWOOFER OUTPUT

■

INDEPENDENT SECOND SOURCE­SELECTOR

■

FULL MIXING CAPABILITY

■

PAUSE DETECTOR

TDA7402

PRODUCT PREVIEW

TQFP44

ORDERING NUMBER: TDA7402

Digital Control:

I2C-BUS INTERFACE

Stereodecoder:

■

RDS MUTE

■ NO EXTERNAL ADJUSTMENTS

■

AM/FM NOISEBLANKER WITH SEVERAL
TRIGGER CONTROLS

■ PROGRAMMABLE MULTIPATH DETECTOR

■

QUALITY DETECTOR OUTPUT

DESCRIPTION

The device includes a high performance audiopro­cessor and a stereodecoder-noiseblanker combina­tion with the whole low frequency signal processing
necessary for state-of-the-art as well as future carra­dios. The digital control allows a programming in a
wide range of all the filter characteristics. Also the
stereodecoder part offers several possibilities of pro­gramming especially for the adaptation to different
IF-devices.

March 2000

This ispreliminary information ona new product now in development. Details are subject to change without notice.

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TDA7402

PIN CONNECTION (Top view)

ESD:

All pins are protected against ESD according to the MIL883 standard.

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

T

V

amb

T

stg

Operating Supply Voltage 10.5 V

S

Operating Temperature Range -40 to 85 °C
Storage Temperature Range -55 to +150 °C

THERMAL DATA

Symbol Parameter Value Unit

R

th j-pins

Thermal Resistance Junction-pins max 65 °C/W

SUPPLY

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

SVRR Ripple Rejection @ 1kHz Audioprocessor (allFilters flat) 60 dB

Supply Voltage 7.5 9 10 V

S

I

Supply Current VS=9V 50 mA

S

Stereodecoder + Audioprocessor 55 dB

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BLOCK DIAGRAM

TDA7402

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TDA7402

Audioprocessor Part Features:

Input Multiplexer 2 fully differential CD stereo inputs with programmable attenuation

1 single-ended stereo input
2 differential mono input
1 single-ended mono input
In-Gain 0..15dB, 1dB steps
internal Offset-cancellation (AutoZero)

separate second source-selector
Beep internal Beep with 4 frequencies
Mixing stage Beep, Phone and Navigation mixable to all speaker-outputs
Loudness programmable center frequency and frequency response

15 x 1dB steps

selectable flat-mode (constant attenuation)
Volume 0.5dB attenuator

100dB range

soft-step control with programmable times
Compander dynamic range compression for use with CD

2:1 compression rate

programmable max. gain
Bass 2nd order frequency response

center frequency programmable in 8 steps

DC gain programmable

+ 15 x 1dB steps
Treble 2nd order frequency response

center frequency programmable in 4 steps

+15 x 1dB steps
Voice Bandpass 2nd order butterworth highpass filter with programmable cut-off frequency

2nd order butterworth lowpass filter with programmable cut-off frequency

selectable flat-mode
Speaker 4 independent speaker controls in 1dB steps

control range 95dB

separate Mute
Subwoofer single-ended stereo output

independent stereo level controls in 1dB steps

control range 95dB

separate Mute
Mute Functions direct mute

digitally controlled SoftMute with 4 programmable mute-times
Pause Detector programmable threshold

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TDA7402

ELECTRICAL CHARACTERISTICS

VS= 9V; T

Symbol Parameter Test Condition Min. Typ. Max. Unit

INPUT SELECTOR

=25°C; RL=10kΩ; all gains = 0dB; f = 1kHz; unless otherwise specified

amb

R

V

S

G

IN MIN

G

IN MAX

G

STEP

V

V

offset

Input Resistance all single ended Inputs 70 100 130 kΩ

in

Clipping Level 2.2 2.6 V

CL

Input Separation 80 100 dB

IN

Min. Input Gain -1 0 +1 dB
Max. Input Gain 15 dB
Step Resolution 1 dB
DC Steps Adjacent Gain Steps 1 mV

DC

Remaining offset with AutoZero 0.5 mV

DIFFERENTIAL STEREO INPUTS

R

Input Resistance

in

(see Figure 1)

G

Gain only at true differential input 0 dB

CD

CMRR Common Mode Rejection Ratio V

RMS

to G

G

MIN

MAX

6mV

Differential 70 100 130 kΩ

-6 dB

-12 dB

CM

=1V

@ 1kHz 46 70 dB

RMS

e

Output-Noise @ Speaker-Outputs 20Hz - 20kHz, flat; all stages 0dB 9 µV

NO

DIFFERENTIAL MONO INPUTS

R

Input Impedance Differential 40 56 k

in

CMRR Common Mode Rejection Ratio V

BEEP CONTROL

V

f

Beep

RMS

Beep Level Mix-Gain = 6dB 350 mV
Beep Frequency f

MIXING CONTROL

M

LEVEL

Mixing Ratio Main / Mix-Source -6/-6 dB

V

CM

CM

V

CM

Beep1

f

Beep2

f

Beep1

f

Beep1

=1V

=1V
=1V

@ 10kHz 46 60 dB

RMS

@ 1kHz 40 70 dB

RMS

@ 10kHz 40 60 dB

RMS

600 Hz
780 Hz

1.56 kHz

2.4 kHz

Ω

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TDA7402

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

G
A

MAX

A

STEP

MULTIPLEXER OUTPUT

R

R
C

V

Max. Gain 15 dB

MAX

Max. Attenuation -79 dB
Attennuation Step 1 dB

1

Output Impedance 225 Ω

OUT

Output Load Resistance 2 k

L

Output Load Capacitance 10 nF

L

DC Voltage Level 4.5 V

DC

LOUDNESS CONTROL

A

A

f

STEP

MAX

Peak

Step Resolution 1 dB
Max. Attenuation 19 dB
Peak Frequency f

P1

f

P2

f

P3

200 Hz
400 Hz
600 Hz

Ω

VOLUME CONTROL

G
A

MAX

A

STEP

E

E

V

Max. Gain 15.5 dB

MAX

Max. Attenuation 79.5 dB
Step Resolution 0.5 dB
Attenuation Set Error G = -20 to +20dB -0.75 0 +0.75 dB

A

Tracking Error 2dB

T

DC Steps Adjacent Attenuation Steps 0.1 3 mV

DC

SOFT MUTE

A

MUTE

T

Mute Attenuation 80 100 dB
Delay Time T1 0.48 ms

D

f

P4

800 Hz

G = -80 to -20dB -4 0 3 dB

From 0dB to G

MIN

0.5 5 mV

T2 0.96 ms
T3 123 ms
T4 324 ms

V

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TH low

Low Threshold forSM-Pin

2

1V

TDA7402

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

TH high

R
V

Notes: 1. If configured as Multiplexer-Output

High Threshold for SM - Pin 2.5 V
Internal pull-up resistor 32 45 58 k

PU

Internal pull-up Voltage 3.3 V

PU

2. The SM-Pin is active low (Mute = 0)

BASS CONTROL

C

RANGE

A

STEP

Control Range +15 dB
Step Resolution 1 dB
Center Frequency f

f

C

C1

f

C2

f

C3

f

C4

f

C5

f

C6

f

C7

60 Hz
70 Hz
80 Hz

90 Hz
100 Hz
130 Hz
150 Hz

Ω

Q

DC

BASS

Quality Factor Q

Bass-DC-Gain DC = off 0 dB

GAIN

TREBLE CONTROL

C

RANGE

A

STEP

Control Range +15 dB
Step Resolution 1 dB
Center Frequency f

f

C

f

C8

1

Q

2

Q

3

Q

4

200 Hz

1

1.25

1.5
2

DC = on 4.4 dB

C1

f

C2

f

C3

f

C4

10 kHz

12.5 kHz
15 kHz

17.5 kHz

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TDA7402

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

PAUSE DETECTOR

V

Zero Crossing Threshold Window 1 40 mV

TH

1

Window 2 80 mV
Window 3 160 mV

I

DELAY

V

Pull-Up Current 15 25 35 µA
Pause Threshold 3.0 V

THP

SPEAKER ATTENUATORS

R
G
A

MAX

A

STEP

A

MUTE

E

V

Input Impedance 35 50 65 kΩ

in

Max. Gain 15 dB

MAX

Max. Attenuation 79 dB
Step Resolution 1 dB
Output Mute Attenuation 80 90 dB
Attenuation Set Error 2dB

E

DC Steps Adjacent Attenuation Steps 0.1 5 mV

DC

Notes: 1. If configured as Pause-Output

AUDIO OUTPUTS

V

R

CLIP

R
C

V

Clipping Level d = 0.3% 2.2 2.6 V
Output Load Resistance 2 kΩ

L

Output Load Capacitance 10 nF

L

Output Impedance 30 120 W

OUT

DC Voltage Level 4.5 V

DC

VOICE BANDPASS

f

Highpass corner frequency f

HP

HP1

f

HP2

f

HP3

f

HP4

f

HP5

f

HP6

f

HP7

f

HP8

RMS

90 Hz
135 Hz
180 Hz
215 Hz
300 Hz
450 Hz
600 Hz
750 Hz

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TDA7402

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

f

Lowpass corner frequency f

LP

LP1

f

LP2

3kHz
6kHz

SUBWOOFER ATTENUATORS

R

G

A

ATTN

A

STEP

A

MUTE

E

V

Input Impedance 35 50 65 k

in

Max. Gain 15 dB

MAX

Max. Attenuation 79 dB
Step Resolution 1 dB
Output Mute Attenuation 80 90 dB
Attenuation Set Error 2dB

E

DC Steps Adjacent Attenuation Steps 1 5 mV

DC

SUBWOOFER Lowpass

f

Notes: 1. If programmed as Subwoofer Diff.-Output

DIFFERENTIAL OUTPUTS

Lowpass corner frequency f

LP

1)

LP1

f

LP2

f

LP3

80 Hz
120 Hz
160 Hz

Ω

R

R

C

LMAX

C

DLMAX

V

Offset

R

V
e

load resistance at each output 1V

L

load resistance differential 1V

DL

Capacitive load at each output C
Capacitive load differential C
DC Offset at pins Output muted -10 10 mV
Output Impedance 30 Ω

OUT

DC Voltage Level 4.5 V

DC

Output Noise Output muted 6 µV

NO

COMPANDER

G

max. Compander Gain Vi < -46dB 19 dB

MAX

; ACcoupled; THD=1% 1 k

RMS

; ACcoupled; THD=1% 2 kΩ

2V

RMS

; ACcoupled; THD=1% 2 kΩ

RMS

; ACcoupled; THD=1% 4 k

2V

RMS

at each Output to Ground 10 nF

Lmax

between Output terminals 5 nF

Lmax

Vi < -46dB, Anti-Clip=On 29 dB

Ω

Ω

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TDA7402

ELECTRICAL CHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

t

Att

t

Rel

REF

Attack time t

Release time t

Compander Reference Input-

Att1

t

Att2

t

Att3

t

Att4

Rel1

t

Rel2

t

Rel3

t

Rel4

V

REF1

6ms
12 ms
24 ms
49 ms

390 ms
780 ms

1.17 s

1.56 s

0.5 V

Level (equals 0dB)

C

Notes: 1. If programmed as Subwoofer Diff.-Output

Compression Factor Output Signal / Input Signal 0.5

F

V
V

REF2

REF3

1.0 V

2.0 V

GENERAL

RMS

RMS

RMS

e

Output Noise BW = 20Hz - 20kHz

NO

all gains = 0dB single endedinputs

S/N Signal to Noise Ratio all gains = 0dB

flat; V

O

=2V

RMS

bass, treble at +12dB;
a-weighted; V

V

IN

OUT

=1V

=1V

RMS

RMS

d distortion V

12dB

S

E

Channel Separation left/right 100 dB

C

TotalTracking Error AV= 0 to -20dB 0 1 dB

T

= -20 to -60dB 0 2 dB

A

V

output muted

10

3

µV
µV

106 dB

100 dB

= 2.6V

O

RMS

; all stages 0dB 0.005 %

; Bass & Treble =

0.05 %

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TDA7402

1.0 DESCRIPTION OF THE AUDIOPROCESSOR PART

1.1 Input stages

In the basic configuration two full-differential, two mono-differential, one single ended stereo and one single­ended mono input are available. In addition a dedicated input for the stereodecoder MPX-signal is present.

Figure 1. Input-stages

Full-differential stereo Input 1 (FD1)

The FD1-input is implemented as a buffered full-differential stereo stage with 100kΩinput-impedance at each
input. The attenuation is programmable in 3 steps from 0 to -12dB in order to adapt the incoming signal level.
A 6dB attenuation is included in the differential stage, the additional 6dBare done by a following resistive divid­er. This input is also configurable as two single-ended stereo inputs (see pin-out).

Full-differential stereo Input 2 (FD2)

The FD2-input has the same general structure as FD1, but with a programmable attenuation of 0 or 6dB em­bedded in the differential stage.

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TDA7402

Mono-differential Input 1 (MD1)

The MD1-input is designed as a basic differential stage with 56kΩ input-impedance. This input is configurable
as a single-ended stereo input (see pin-out).

Mono-differential Input 2 (MD2)

The MD2-input has the same topology as MD1, but without the possibility to configure it to single ended.

Single-endedstereo Input (SE1), single-ended mono input (AM) and FM-MPX input

All single ended inputs offer an input impedance of 100kΩ. The AM-pin can be connected by software to the
input of the stereo-decoder in order to use the AM-noiseblanker and AM-High-Cut feature.

1.2 AutoZero

The AutoZero allows a reduction of the number of pins as well as external components by canceling any offset
generated by or before the In-Gain-stage (Please notice that externally generated offsets, e.g. generated
through the leakage current of the coupling capacitors, are not canceled).

The auto-zeroing is started every time the DATA-BYTE 0 is selected and needs max.
To avoidaudible clicks the Audioprocessor is muted before the loudness stage during this time. The AutoZero­feature is only present in the main signal-path.

0.3ms for the alignment.

AutoZero for Stereodecoder-Selection

A special procedure is recommended for selecting the stereodecoder at the main input-selector to guarantee
an optimum offset-cancellation:

(Step 0: SoftMute or Mute the signal-path)
Step 1: Temporary deselect the stereodecoder at all input-selectors
Step 2: Configure the stereodecoder via IIC-Bus
Step 3: Wait 1ms
Step 4: Select the stereodecoder at the main input-selector first
The root cause of this procedure is, that after muting the stereodecoder (Step 1), the internal stereodecoder

filters have to settle in order to perform a proper offset-cancellation.

AutoZero-Remain

In some cases, for example if the µP is executing a refresh cycle of the IIC-Bus-programming, it is not useful
to start a new AutoZero-action because no new source is selected and an undesired mute would appear at the
outputs. For such applications the A619 could be switched in the
dress-byte). If this bit is set to high, the DATABYTE 0 could be loaded without invoking the AutoZero and the
old adjustment-value remains.

AutoZero-Remain-Mode (Bit 6 of the subad-

1.3 Pause Detector / MUX-Output

The pin number 40(Pause/MUX) is configurable for two different functions:

1. During Pause-Detector OFF this pin is used as a mono-output of the maininput-selector. This signal is often
used to drive a level-/equalizer-display on the carradio front-panel.

2. DuringPause-Detector ON the pin isused todefine the time-constant ofthe detector by an externalcapacitor.
The pause-detector is driven by the internal stereodecoder-outputs in order to use pauses in the FM-signal
for alternate-frequency-jumps. If the signal-level of both stereodecoder channels is outside the programmed
voltage-window, the external capacitor is abruptly discharged. Inside the pause-condition the capacitor is
slowly recharged bya constant current of 25µA. The pause information is also available via IIC-Bus (see IIC­Bus programming).

12/59

1.4 Loudness

There are four parameters programmable in the loudness stage:

1.4.1 Attenuation

Figure 2 shows the attenuation as a function of frequency at fP= 400Hz

Figure 2. Loudness Attenuation @ fP= 400Hz.

0.0

-5.0

-10.0

dB

-15.0

-20.0

TDA7402

-25.0

10.0 100.0 1.0K 10.0K

Hz

1.4.2 Peak Frequency

Figure 3 shows the four possible peak-frequencies at 200, 400, 600 and 800HzFigure 3: Loudness Center fre­quencies @ Attn. = 15dB

Figure 3. Loudness Center frequencies @ Attn. = 15dB.

0.0

-5.0

dB

-10.0

-15.0

-20.0

10.0 100.0 1.0K 10.0K

Hz

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TDA7402

1.4.3 Loudness Order

Different shapes of 1st and 2nd-Order Loudness

Figure 4. 1st and 2nd Order Loudness @ Attn. = 15dB, fP=400Hz

0.0

-5.0

dB

-10.0

-15.0

-20.0

10.0 100.0 1.0K 10.0K

1.4.4 Flat Mode

In flat mode the loudness stage works as a 0dB to -19dB attenuator.

Hz

1.5 SoftMute

The digitally controlled SoftMute stage allows muting/demuting the signal with a I2C-bus programmable slope.
The mute process can either be activated by the SoftMute pin or by the I

2

C-bus. This slope is realized in a spe-

cial S-shaped curve to mute slow in the critical regions (see Figure 5).
For timing purposes the Bit0 of the I

2

C-bus output register is setto 1 from the start ofmuting until the end of de-

muting.

Figure 5. Softmute-Timing

Note: Please notice that a started Mute-action is always terminated and could not be interrupted by a change of the mute -signal.

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TDA7402

1.6 SoftStep-Volume

When the volume-level is changed audible clicks could appear at the output. The root cause of those clicks
could either be a DC-Offset before the volume-stage or the sudden change of the envelope of the audiosignal.
With the SoftStep-feature both kinds of clicks could be reduced to a minimum and are no more audible. The
blend-time from one step to the next is programmable in four steps.

Figure 6. SoftStep-Timing

1dB

0.5dB

SS Time

-0.5dB

-1dB

Note: For steps more than 0.5dB theSoftStep mode should bedeactivated because it could generate a hard 1dB stepduring the blend-time.

1.7 Bass

There are four parameters programmable in the bass stage:

1.7.1 Attenuation

Figure 7 shows the attenuation as a function of frequency at a center frequency of 80Hz.

Figure 7. Bass Control @ fC= 80Hz, Q = 1

15.0

10.0

5.0

dB

0.0

-5.0

-10.0

-15.0

10.0 100.0 1.0K 10.0K

Hz

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TDA7402

1.7.2 Center Frequency

Figure 8 shows the eight possible center frequencies 60, 70, 80, 90, 100, 130, 150 and 200Hz.

Figure 8. Bass center Frequencies @ Gain = 14dB, Q = 1

15.0

12.5

10.0

7.5

dB

5.0

2.5

0.0

10.0 100.0 1.0K 10.0K

Hz

1.7.3 Quality Factors

Figure 9 shows the four possible quality factors 1, 1.25, 1.5 and 2.

Figure 9. Bass Quality factors @ Gain = 14dB, fC= 80Hz

15.0

12.5

10.0

7.5

5.0

2.5

0.0

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10.0 100.0 1.0K 10.0K

TDA7402

1.7.4 DC Mode

In this mode the DC-gainis increased by 4.4dB. In addition the programmed center frequency and quality factor
is decreased by 25% which can be used to reach alternative center frequencies or quality factors.

Figure 10. Bass normal and DC Mode @ Gain = 14dB, fC= 80Hz

15.0

12.5

10.0

7.5

5.0

2.5

0.0

10.0 100.0 1.0K 10.0K

Note: The center frequency, Q and DC-mode can be set fully independently.

1.8 Treble

There are two parameters programmable in the treble stage:

1.8.1 Attenuation

Figure 11 shows the attenuation as a function of frequency at a center frequency of 17.5kHz.

Figure 11. Treble Control @ fC= 17.5kHz

15.0

10.0

5.0

0.0

-5.0

-10.0

-15.0

10.0 100.0 1.0K 10.0K

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TDA7402

1.8.2 Center Frequency

Figure 12 shows the four possible center frequencies 10k, 12.5k, 15k and 17.5kHz.

Figure 12. Treble Center Frequencies @ Gain = 14dB

15.0

12.5

10.0

7.5

5.0

2.5

0.0

10.0 100.0 1.0K 10.0K

1.9 Subwoofer Application

Figure 13. Subwoofer Application with LPF 80/120/160Hz and HPF 90/135/180Hz

0.0

-10.0

-20.0

dB

-30.0

-40.0

-50.0

10.0 100.0 1.0K 10.0K

Hz

Both filters, the lowpass- as well as the highpass-filter, have butterworth characteristic so that their cut-off fre­quencies are not equal but shifted by the factor 1.125 to get a flat frequency response.

18/59