® TDA7461N
CAR RADIO SIGNAL PROCESSOR
HIGH PERFORMANCE SIGNAL PROCES-
SOR FOR CAR RADIO SYSTEMS
DEVICE INCLUDES AUDIO PROCESSOR,
STEREO DECODER, NOISEBLANKER AND
MULTIPATH DETECTOR
NO EXTERNAL COMPONENTS REQUIRED
FULLY PROGRAMMABLE VIA I2C BUS
LOW DISTORTION
LOW NOISE
DESCRIPTION
The TDA7461N is a high performance signal
processor specifically designed for car radio ap-
plications.
The device includes a complete audioprocessor
and a stereo decoder with noiseblanker,
stereoblend and all signal processing functions
necessary for state-of-the-art as well as future car
radio systems.
Switched-capacitors design technique allows to
obtain all these features without external compo-
BLOCK DIAGRAM
SO28
ORDERING NUMBER: TDA7461ND
nents or adjustments. This means that higher
quality and reliability walks alongside an overall
cost saving.
The CSP is fully programmable by I2C bus inter-
face allowing to customize key device parameters
and especially filter characteristics.
The BICMOS process combined with the opti-
mized signal processing assure low noise and
low distortion performances.
CDL CDG CDR
765
10
AM
CASS R
CASS L
3
4
9
PHONE
INPUT
MULTIPLEXER
+
AUTO ZERO
MIXING
STAGE
PHONE
BEEP
8
PH GND
LOUDNESS
VOLUME
SMUTE
17
SOFT
MUTE
TREBLE
DIGITAL CONTROL
28
BASS
27 1 2
23
OUT LR
OUT LR
25
OUT LF
OUT LF
22
OUT RR
OUT RR
24
OUT RF
OUT RF
I2C BUS
18
SCL
19
SDA
16
MUX R
15
MUX L
11
MPX
80KHz
LP
PILOT
CANCELLATION
DEMODULATOR
+ STEREO ADJUST
+ STEREO BLEND
25KHz
LP
S &H
HIGH
CUT
CONTROL
21
VS
SUPPLY
20 26
GND CREF
PLL
PIL
DET
MULTIPATH-
DETECTOR
13
MPIN
14
MPOUT
NOISE
BLANKER
PULSE
FORMER
D
A
12
LEVEL
D97AU646A
June 2000
1/31








TDA7461N
ELECTRICAL CHARACTERISTICS (continued)
Symbol
Parameter
Test Condition
BASS CONTROL
CRANGE Control Range
ASTEP Step Resolution
fC Center Frequency
QBASS Quality Factor
DCGAIN Bass-Dc-Gain
fC1
fC2
fC3
fC4
Q1
Q2
Q3
Q4
DC = off
DC = on
TREBLE CONTROL
CRANGE Control Range
ASTEP Step Resolution
fC Center Frequency
fC1
fC2
fC3
fC4
SPEAKER ATTENUATORS
CRANGE Control Range
ASTEP Step Resolution
AMUTE Output Mute Attenuation
EE Attenuation Set Error
VDC DC Steps
Adjacent Attenuation Steps
AUDIO OUTPUTS
VCLIP
Clipping Level
RL Output Load Resistance
CL Output Load Capacitance
ROUT
Output Impedance
VDC DC Voltage Level
d = 0.3%
GENERAL
eNO Output Noise
S/N Signal to Noise Ratio
d Distortion
SC Channel separation Left/Right
ET Total Tracking Error
BW = 20 Hz to 20 KHz
output muted
BW = 20 Hz to 20 KHz
all gain = 0dB
all gain = 0dB flat; VO = 2VRMS
bass treble at 12dB; VO =
2.6VRMS
VIN = 1VRMS; all stages 0dB
VIN = 1VRMS; Bass & Treble = 12dB
AV = 0 to -20dB
AV = -20 to -60dB
2) See description of Audioprocessor Part - Bass & Treble filter characteristics programming
Min.
±13
1
54
63
72
90
0.9
1.1
1.3
1.8
-1
4
±13
1
8
10
12
14
-53
0.5
80
-2
2.2
2
3.6
80
-1
-2
Typ.
±14
2
60
70
80
100(2)
1
1.25
1.5
2
0
4.4
±14
2
10
12.5
15
17.5
-50
1
90
0.1
2.6
30
3.8
3
6.5
106
100
0.002
0.05
100
0
0
Max.
±15
3
66
77
88
110
1.1
1.4
1.7
2.2
+1
6
±15
3
12
15
18
21
-47
2
2
5
10
100
4.0
15
15
0.1
0.1
1
2
Unit
dB
dB
Hz
Hz
Hz
Hz
dB
dB
dB
dB
KHz
KHz
KHz
KHz
dB
dB
dB
dB
mV
VRMS
KΩ
nF
Ω
V
µV
µV
dB
dB
%
%
dB
dB
dB
6/31

6 Page









TDA7461N
STEREODECODER PART
No external components necessary
PLL with adjustment free fully integrated VCO
Automatic pilot dependent MONO/STEREO
switching
Very high suppression of intermodulation and
interference
Programmable Roll-Off compensation
Dedicated RDS Softmute
Highcut and Stereoblend characterisctics pro-
grammable in a wide range
Internal Noiseblanker with threshold controls
Multipath detector with programmable inter-
nal/external influence
I2C bus control of all necessary functions
ELECTRICAL CHARACTERISTICS (VS = 9V; deemphasis time constant = 50µs, VMPX = 500mV,
75KHz deviation, f = 1KHz. GI = 6dB, Tamb = 25°C; unless otherwise specified).
Symbol
VIN
Rin
Gmin
Gmax
GSTEP
SVRR
α
THD
S+ N
N
Parameter
MPX Input Level
Input Resistance
Minimum Input Gain
Max Input Gain
Step Resolution
Supply Voltage Ripple Rejection
Max Channel Separation
Total Harmonic Distortion
Signal plus Noise to Noise Ratio
Test Condition
Input Gain = 3.5dB
Vripple = 100mv, f = 1khz
S = 2Vrms
Min.
70
1.5
8.5
1.75
30
80
Typ.
0.5
100
3.5
11
2.5
55
50
0.02
91
Max.
1.25
130
4.5
12.5
3.25
0.3
Unit
VRMS
KΩ
dB
dB
dB
dB
dB
%
dB
MONO/STEREO SWITCH
VPTHST1 Pilot Threshold Voltage
VPTHST0 Pilot Threshold Voltage
VPTHMO1 Pilot Threshold Voltage
VPTHMO0 Pilot Threshold Voltage
for Stereo, PTH = 1
for Stereo, PTH = 0
for Mono, PTH = 1
for Stereo, PTH = 0
PLL
∆f/f
Capture Range
DEEMPHASIS and HIGHCUT (5)
τHC50
Deemphasis Time Constant
τHC75
Deemphasis Time Constant
τHC50
Highcut Time Constant
τHC75
Highcut Time Constant
Bit = 7, Subadr. 10 = 0
VLEVEL >> VHCH
Bit = 7, Subadr. 10 = 1
VLEVEL >> VHCH
Bit = 7, Subadr. 10 = 0
VLEVEL >> VHCL
Bit = 7, Subadr. 10 = 1
VLEVEL >> VHCL
STEREOBLEND and HIGHCUT-CONTROL
REF5V Internal Reference Voltage
TCREF5V Temperature Coefficient
LGmin
Min. LEVEL Gain
LGmax
Max. LEVEL Gain
LGstep
LEVEL Gain Step Resolution
VSBLmin Min.Voltage for Mono
VSBLmax Max. Voltage for Mono
VSBLstep Step Resolution
10 15 25 mV
15 25 35 mV
7 12 17 mV
10 19 25 mV
0.5 %
25 50 75
50 75 100
100 150 200
150 225 300
µs
µs
µs
µs
4.7 5 5.3 V
3300
ppm
-1 0 +1 dB
8 10 12 dB
0.3 0.67 1.0
dB
29 33 37 %REF5V
54 58 62 %REF5V
5.0 8.4
12 %REF5V
12/31

12 Page