SGS Thomson Microelectronics TDA7460ND Datasheet



CAR RADIO SIGNAL PROCESSOR

DEVICE INCLUDES AUDIO PROCESSOR, STEREO DECODER, NOISEBLANKER AND MULTIPATHDETECTOR

HIGH PERFORMANCE SIGNAL PROCESSOR

NO EXTERNALCOMPONENTSREQUIRED FULLY PROGRAMMABLEVIAI LOW DISTORTION LOW NOISE

C BUS

TDA7460N

SO20

DESCRIPTION

The TDA7460N is a high performance signal processor specifically designed for car radio applications.

The device includes a complete audioprocessor and a stereo decoder with noiseblanker, stereoblend and all signal processing functions necessary for state-of-the-artas well as future car radio systems.

Switched-capacitors design technique allows to obtain all these features without external compo-

BLOCK DIAGRAM

PHONE

(MPOUT)

CASS R

CASS L

PHONE

(MPIN)

GND

CDL CDG CDR

INPUT

MULTIPLEXER

AUTO ZERO

345 11 17

MIXING

STAGE

PHONE

FM R

FM L

LOUDNESS

BEEP

ORDERING NUMBER: TDA7460ND

nents or adjustments. This means that higher quality and reliability walks alongside an overall cost saving.

The CSP is fully programmable by I face allowingto customize key device parameters and especiallyfilter characteristics.

The BICMOS process combined with the optimized signal processing assure low noise and low distortionperformances.

SMUTE

OUT LR

VOLUME BASSTREBLE

SOFT MUTE

DIGITAL CONTROL

OUT LF OUT RR OUT RF

C BUS

C bus inter-

OUT LR

OUT LF

OUT RR

OUT RF

SCL

SDA

MPX

June 2000

80KHz

SUPPLY

14 20

CREF

GND

PILOT

CANCELLATION

PLL

PIL

DET

DEMODULATOR

+ STEREO

ADJUST

+ STEREO BLEND

MULTIPATH-

DETECTOR

25KHz

NOISE

BLANKER

S&H

PULSE

FORMER

HIGH

CUT

CONTROL

LEVEL

D97AU629A

1/31

TDA7460N

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

amb Operating Ambient Temperature Range -40 to 85 °C

stg Storage Temperature Range -55 to 150 °C

SUPPLY

Symbol Parameter Test Condition Min. Typ. Max. Unit

S Supply Voltage 7.5 9 10 V

S Supply Current V

SVRR Ripple Rejection @ 1KHz Audioprocessor (all filters flat) 60 dB

ESD

All pins are protected against ESD according to the MIL883standard.

PIN CONNECTION

Operating Supply Voltage 10.5 V

=9V 253035mA

Stereodecoder + Audioprocessor 45 dB

CASS R

CASS L

CDR

CDGND

CDL

PHGND (MPOUT)

PHONE (MPIN)

MPX SCL

LEVEL SMUTE

2 3 4 5 6 7 8 9 10

20 19 18 17 16 15 14 13 12 11

D97AU628A

CREF1 OUT LF OUT RF OUT LR OUT RR V

GND SDA

THERMAL DATA

Symbol Parameter Value Unit

th-j pins

Thermal Resistance Junction-pins Max 85 °C/W

2/31

TDA7460N

PIN DESCRIPTION

N. Name Function Type

1 CASSR Cassette Input Right I 2 CASSL Cassette Input Left I 3 CDR CD Right ChannelInput I 4 CDGND Ground reference CD I 5 CDL CD Left ChannelInput I 6 PHGND Phone Ground (MPOUT selectable by SW 7 PHONE Phone Input (MPIN selectable by SW 8 AM AM Input I

9 MPX FM Input (MPX) I 10 LEVEL Level Input Stereodecoder I 11 SMUTE Soft Mute Drive I 12 SCL I 13 SDA I

C Clock Line I/O

C Data Line I/O 14 GND Supply Ground S 15 VS Supply Voltage S 16 OUTRR Right Rear Speaker Output O 17 OUTLR Left Rear Speaker Output O 18 OUTRF Right Front Spaeaker Output O 19 OUTLF Left Front Speaker Output O 20 CREF Reference Capacitor Pin S

(1) See input configuration tree and databyte specification ”configuration” Pin type legenda: I = Input O = Output I/O = Input/Output S = Supply

3/31

TDA7460N

AUDIO PROCESSORPART

Input Multiplexer

Fully differential or quasi-differential CD and cassettestereo input

AM monoor stereoinput Phonedifferential or single ended input

Bass Control

2nd order frequencyresponse Center frequencyprogrammablein 4(5) steps DC gain programmable 7 x2dB steps

Internalbeep with 2 frequencies(selectable) Mixablephone and beep signals

Treble Control

2nd order frequencyresponse

Loudness

Firstor second order frequencyresponse

Center frequencyprogrammablein 4 steps 7 x2dB steps

Program mablecenterfrequencyand qualityfactor 15 x 1dB steps Selectableflat-mode (constantattenuation)

Speaker Control

4 independentspeaker controls (1dB steps controlrange 50dB)

Volume control

1dB attenuator Max. gain 20dB Max. attenuation79dB Soft-stepgain control

ELECTRICALCHARACTERISTICS (V

S = 9V; Tamb =25°C; RL = 10KΩ;all gains = 0dB; f = 1KHz;

Mute Functions

Direct mute Digitally controlled softmute with 4 program-

mabletime constants

unless otherwisespecified).

Symbol Parameter Test Condition Min. Typ. Max. Unit

INPUTSELECTOR

Rin Input Resistance all inputs except Phone 70 100 130 KΩ

Clipping Level 2.2 2.6 V Input Separation 80 100 dB Min. Input Gain -1 0 1 dB Max. Input Gain 13 14 15 dB Step Resolution 1 2 3 dB DC Steps Adjacent Gain Step -5 0 +5 mV

to G

MIN

MAX

-5 1 +5 mV

IN IN MIN IN MAX

STEP

DIFFERENTIAL CD STEREO INPUT

CMRR Common Mode Rejection Ratio V

N Output Noise @ Speaker

Input Resistance Differential 70 100 130 K

Common Mode 20 30 40 K

@ 1KHz 45 70 dB

915µV

Output

CM=1VRMS CM =1VRMS @ 10KHz 45 60 dB

V 20Hz to 20KHz flat; all stages

0dB

DIFFERENTIAL PHONE INPUT

Rin Input Resistance Differential 10 15 20 KΩ

Common Mode 20 30 40 K

CMRR Common Mode Rejection Ratio V

CM=1VRMS

@ 1KHz 45 70 dB @ 10KHz 45 60 dB

RMS

Ω Ω

Ω

4/31

TDA7460N

ELECTRICALCHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

BEEPCONTROL

VRMS Beep Level 250 350 500 mV

BMIN Lower Beep Frequency 570 600 630 Hz

BMAX

Higher Beep Frequency 1.15 1.2 1.25 KHz

MIXINGCONTROL

MLEVEL Mixing Level Source -1 0 1 dB

Source -5 -6 -7 dB Source -10 -12 -14 dB Beep/Phone -1 0 1 dB

VOLUMECONTROL

MAX

STEP

T Tracking Error 2dB

DC DC Steps Adjacent Attenuation Steps -3 0.1 3 mV

Max Gain 19 20 21 dB Max Attenuation -83 -79 -75 dB Step Resolution 0.5 1 1.5 dB Attenuation Set Error G = -20 to 20dB -1.25 0 1.25 dB

G = -60 to 20dB -4 0 3 dB

From 0dB to G

MIN -7 0.5 +7 mV

LOUDNESSCONTROL

STEP

MAX

CMIN Lower Center Frequency 180 200 220 Hz

CMAX Higher CenterFrequency 360 400 440 Hz

Step Resolution 0.5 1 1.5 dB Max. Attenuation -16 -15 -14 dB

SOFTMUTE

MUTE

THlow Low Threshold for SM Pin

THhigh High Threshold for SM Pin 2.5 V

PU Internal Pull-up Resistor 70 100 130 KΩ

R V

Mute Attenuation 60 100 dB Delay Time T1 0.48 1 ms

T2 0.96 2 ms T3 20 40.4 60 ms T4 200 324 600 ms

Pull-up Voltage 4.7 V

SOFTSTEP

1) The SM pin is active low (Mute = 0)

Switch Time 5 10 15 ms

5/31

TDA7460N

ELECTRICALCHARACTERISTICS

(continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

BASSCONTROL

CRANGE Control Range ±13 ±14 ±15 dB

STEP Step Resolution 1 2 3 dB

BASS Quality Factor Q1 0.9 1 1.1

GAIN

Center Frequency f

2 1.1 1.25 1.4

54 60 66 Hz 63 70 77 Hz 72 80 88 Hz 90 100

(2)

110 Hz

1.3 1.5 1.7

1.8 2 2.2

Bass-Dc-Gain DC = off -1 0 +1 dB

DC = on 4 4.4 6 dB

TREBLECONTROL

RANGE

STEP

Control Range

15 dB

Step Resolution 1 2 3 dB Center Frequency f

C2 10 12.5 15 KHz

8 10 12 KHz

12 15 18 KHz 14 17.5 21 KHz

SPEAKERATTENUATORS

CRANGE Control Range -53 -50 -47 dB

STEP

MUTE

Step Resolution 0.5 1 2 dB Output Mute Attenuation 80 90 dB Attenuation Set Error -2 2 dB DC Steps Adjacent Attenuation Steps 0.1 5 mV

AUDIO OUTPUTS

CLIP

L Output LoadCapacitance 10 nF

OUT Output Impedance 30 100 Ω

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

DC Voltage Level 3.6 3.8 4.0 V

GENERAL

S/N Signal to Noise Ratio all gain= 0dB flat; V

d Distortion V

C Channel separation Left/Right 80 100 dB

2) See description of Audioprocessor Part - Bass & Treble filter characteristics programming

Output Noise BW = 20 Hz to 20 KHz

315µV

output muted BW = 20 Hz to 20 KHz

6.5 15 µV

all gain = 0dB

=2V

RMS

bass treble at12dB; V

2.6V

RMS

=1V

IN =1VRMS;Bass& Treble= 12dB 0.05 0.1 %

; all stages0dB 0.002 0.1 %

RMS

O =

106 dB 100 dB

Total Tracking Error AV= 0 to -20dB -1 0 1 dB

= -20 to -60dB -2 0 2 dB

RMS

Ω

6/31

TDA7460N

DESCRIPTIONOFTHE AUDIOPROCESSOR PART

ProgrammableInput Matrix

The programmableinput matrix of the TDA7460N offers several possibilities to adapt the audioprocessor to the desired application. In to the standard applicationwe have:

CD quasi differential Cassettestereo Phonedifferential AM mono Stereodecoderinput.

The input matrixcan be configuredby only 2 bits:

Figure 1. InputConfiguration Tree

bits 3 and 4 of subaddress 0. Basically the bit of subaddress 13 is fixed by the applicationand has to be programmed only once at the startup of the IC.

For many configurations the two bits are also fixed during one application(e.g.the standardapplication) and a change of the input source can be done by loading the first three bits of subaddress 0.

In other configurations for some sources a programming of bit 3 and 4 of subaddress0 is necessary in addition to the three source selection bits. In every case only the subaddress 0 has to be changedto switch from one sourceto another.

The followingpicture shows the input and source programmingflow:

TDA7460

MULTIPATH

CD QD CD FD

APPL. 2APPL. 1 APPL. 3 APPL. 5APPL. 4 APPL. 6

CD QD

CASSETTE

FM STD

AM MONO

PHONE (D)

Note: in AMSTD configuration theAM monosignal is lead through the FMstereodecoderpart touse its additionalfilters and high-cutfunction.

CD QD

CASSETTE

FM STD

STEREO

PHONE (SE)

CD QD

CASSETTE

FM STD AM STD

PHONE (D)

CD FD

CASSETTE

FM STD

AM MONO

PHONE (SE)

CD FD

CASSETTE

FM STD

AM STEREO

CD FD

CASSETTE

FM STD AM STD

PHONE (SE)

CD QD

CASSETTE

FM STD

AM MONO

CD QD

MULTIPATH

APPL. 8APPL. 7

CD QD

CASSETTE

FM STD AM STD

CD FD

D98AU851

7/31

TDA7460N

PIN NUMBER

Appl. No 4 6 7 8 Programming

1CD 2CD

3CD

4 CDR 5 CDR

6 CDR

7CD 8CD

Syntax 0/xxx11100 means: SUBADDRESS= 0 - DATA BYTE = xxx11100 (x - don’t care)

GND GND

GND

GND CDLGND Phone AMMONO Startup: 0/xxxx0xxx GND CDLGND AMRIGHT AMLEFT Startup: 0/xxxx0xxx

GND

GND MPOUT MPIN AMMONO Startup: 0/xxx11xxx GND MPOUT MPIN AMSTD Startup: 0/xxx1xxx

How to find the right input configuration

The best way to come to the desired configuration may be to go through the application tree from the top to the bottom while making the specific decisions.

This way will lead to one of the six possibleapplications. Then take the number of the application and go into the pinning table. Here you will find the special pinout as well as the specialprogramming codes for selecting sources.

For example in Appl. 6 the TDA7460N has to be configured while startup with the databyte 0/xxxx0xxx.

To select the FM, AM or phone source the last five significant bits of subaddress 0 have to be changed, for any other source the last three bits are sufficient(see data byte specification).

Input stages

Most of the input circuits are the same as in preceeding ST audioprocessors with exception of the CD inputs (see figure2). In the meantime there are some CD players in the market having a significant high source impedance which affects strongly the commonmode rejection of the normal differential input stage. The additional buffer of the CD input

Phone

GND

Phone AM

Phone

GND

CDL

GND

Phone AM

Phone AMSTD Startup: 0/xxxx1xxx

Phone AMSTD Startup: 0/xxxx0xxx

RIGHT

Startup: 0/xxx11xxx Startup: 0/xxxx1xxx FM

AM Phone

FM AM Phone

FM AM

FM AM Phone

FM AM

MONO LEFT

avoids this drawbackand offers the full commonmoderejection even with those CD players.

The TDA7460N can be configured with an additional input; if the AC couplingbefore the speaker stage is not used (bit 7 in subaddress5set to ”1”) ACINL and ACINR pins can be used as an additional stereo input.

AutoZero

In order to reduce the number of pins there is no AC coupling between the In-Gain and the following stage, so that any offset generated by or before the In-Gain stage would be transferred or even amplified to the output.

To avoid that effect a special offset cancellation stage called AutoZerois implemented. To avoid audible clicks the audioprocessor is muted before the loudness stage during this time. In some cases, for example if the µP is executing a refresh cycle of the I

C bus programming, it is not usefulto start a newAutoZero action because no newsource is selectedand an undesiredmute would appear at the outputs. For such applications the TDA7460N could be switched in the ”Auto Zero Remain” mode (Bit 6 of the subaddress byte). If this bit is set to high, the DATABYTE 0 could be loaded without invoking the AutoZeroand the old adjustmentvalue remains.

0/xxx11100 0/xxx01011 0/xxx11010

0/xxx11100 0/xxx01100 0/xxx11010

0/xxx10100 0/xxx00011

0/xxx10100 0/xxx00100 0/xxx10010

0/xxx11100 0/xxx01100

8/31

Figure 2. Inputstages

TDA7460N

100K

CDGND

PHONE

PH_GND

CASSETTE

100K

MPX

100K

15K 15K

STEREODECODER

Mixing Stage

This stage offers the possibilityto mix the internal beep or the phone signal to any other source. Due to the fact that the mixing stage is also located behind the In-Gain stage fine adjustments of the main source level can be donein this way.

IN GAIN

D97AU633A

Figure 3. Loudness Attenuation @ fc = 400Hz

(secondorder)

0.0

-5.0

Loudness

There are four parameters programmable in the loudnessstage (see fig. 3, 4, 5):

- Attenuation

- Center Frequency

- LoudnessQ

- Flat Mode: in this mode the loudnessstageworks asa 0 - 15dBattenuator.

Softmute

The digitally controlled softmute stage allows muting/demuting the signal with a I grammable slope. The mute process can either be activated by the softmute pin or by the I

C bus pro-

bus. The slope is realized in a special S shaped curve to mute slow in the critical regions (see figure 6).

For timing purposes the Bit 3 of the I

C bus output registeris set to 1 from the start of muting until the end of demuting.

-10.0

-15.0

-20.0

10.0 100.0 1.0K 10.0K

Figure 4. Loudness Center frequency @ Attn.

= 15dB (second order)

0.0

-5.0

-10.0

-15.0

-20.0

10.0 100.0 1.0K 10.0K

9/31

TDA7460N

Figure 5. Loudness @ Attn.= 15dB, fc = 400Hz

(dB)

-5

-10

-15

-20 10 100 1,000 Hz

D98AU844

Softstep Volume

When volume level is changed often an audible click appears at the output. The root cause of those clicks could be either a DC offset before the volume stage or the sudden change of the envelope of the audio signal. With the Softstep feature both kinds of clickscould be reduced to a minimum and are no moreaudible(see figure 7).

Bass

There are three parameters programmable in the bass stage (see figs 8, 9, 10,11):

Figure 6. Softmute Timing

EXT.

MUTE

+SIGNAL

REF

-SIGNAL

BUS

OUT

D97AU634

Note: Please notice that a startedMute actionis always terminated and could not be interrupted by a change of the mute signal.

Time

Figure 7. SoftStep Timing

VOUT

2dB

1dB

- Attenuation

- Center Frequency (60, 70, 80 and 100Hz)

- Quality Factors (1, 1.25, 1.5 and 2)

DC Mode

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

Treble

There are two parameters programmable in the treblestage (see figs 12, 13):

- Attenuation

- Center Frequency (10, 12.5, 15 and17.5kHz).

Speaker Attenuator

Due to practicalaspects the stepsin the speaker attenuators are not linear over the full range. At attenuations more than 24dB the steps increase from 1.5dB to 10dB (please see data byte specification).

10ms

-1dB

-2dB

Note: For steps more than 1dB the softstep mode should be deactivated because it could generate a 1dB error during the blend-time

Time

D97AU635

10/31

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