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 I
2
C 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-
nents or adjustments. This means that higher
quality and reliability walks alongside an overall
cost saving.
The CSP is fully programmable by I
2
C 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.
June 2000
SUPPLY
LOUDNESS
DEMODULATOR
+ STEREO ADJUST
+ STEREO BLEND
CREF
MPIN
OUT LR
D97AU646A
DIGITAL CONTROL
PILOT
CANCELLATION
VS
CASS L
INPUT
MULTIPLEXER
+
AUTO ZERO
PH GND
BEEP
MPX
MIXING
STAGE
VOLUME
BASS
TREBLE
OUT LR
OUT LF
OUT RR
OUT RF
OUT LF
OUT RR
OUT RF
SCL
SDA
80KHz
LP
PLL
25KHz
LP
S & H
HIGH
CUT
CONTROL
MULTIPATH-
DETECTOR
PULSE
FORMER
D
MPOUT
LEVEL
CDL
CDG
CDR
AM
CASS R
PHONE
GND
SMUTE
PHONE
SOFT
MUTE
PIL
DET
I
2
C BUS
NOISE
BLANKER
A
MUX R
MUX L
ACOUTL
ACOUTR
ACINL
ACINR
7
6
5
10
3
4
9
8
11
21
20
26
13
14
12
23
25
22
24
18
19
16
15
2
1
27
28
17
BLOCK DIAGRAM
SO28
ORDERING NUMBER: TDA7461ND
TDA7461N
CAR RADIO SIGNAL PROCESSOR
1/31
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
S
Operating Supply Voltage
10.5
V
T
amb
Operating Ambient Temperature Range
-40 to 85
C
T
stg
Storage Temperature Range
-55 to 150
C
SUPPLY
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
S
Supply Voltage
7.5
9
10
V
I
S
Supply Current
V
S
= 9V
25
30
35
mA
SVRR
Ripple Rejection @ 1KHz
Audioprocessor (all filters flat)
60
dB
Stereodecoder + Audioprocessor
45
dB
ESD
All pins are protected against ESD according to the MIL883 standard.
THERMAL DATA
Symbol
Parameter
Value
Unit
R
th-j pins
Thermal Resistance Junction-pins
Max
85
C/W
ACINL
ACINR
CASSR
CASSL
CDR
CDL
CDGND
PH GND
PHONE
GND
VS
OUTRR
OUTRF
OUTLR
OUTLF
CREF
ACOUTR
ACOUTL
1
3
2
4
5
6
7
8
9
26
25
24
23
22
20
21
19
27
10
28
AM
SDA
D97AU647
MPX
LEVEL
MPIN
MUXR
SMUTE
SCL
11
12
13
18
16
17
15
14
MPOUT
MUXL
PIN CONNECTION
TDA7461N
2/31
PIN DESCRIPTION
N.
Name
Function
Type
1
ACINL
Speaker Stage Input Left
I
2
ACINR
Speaker Stage Input Right
I
3
CASSR
Cassette Input Right
I
4
CASSL
Cassette Input Left
I
5
CDR
CD Right Channel Input
I
6
CDGND
Ground reference CD
I
7
CDL
CD Left Channel Input
I
8
PHGND
Phone Ground
I
9
PHONE
Phone Input
I
10
AM
AM Input
I
11
MPX
FM Input (MPX)
I
12
LEVEL
Level Input Stereodecoder
I
13
MPIN
Multipath Detector Input
I
14
MPOUT
Multipath Detector Output
O
15
MUXL
Multiplexer Output Left Channel (Stereodecoder Output left selectable
1
)
O
16
MUXR
Multiplexer Output Right Channel (Stereodecoder Output right selectable
1
)
O
17
SMUTE
Soft Mute Drive
I
18
SCL
I
2
C Clock Line
I/O
19
SDA
I
2
C Data Line
I/O
20
GND
Supply Ground
S
21
VS
Supply Voltage
S
22
OUTRR
Right Rear Speaker Output
O
23
OUTLR
Left Rear Speaker Output
O
24
OUTRF
Right Front Spaeaker Output
O
25
OUTLF
Left Front Speaker Output
O
26
CREF
Reference Capacitor Pin
S
27
ACOUTR
Pre-speaker AC Output Right Channel
O
28
ACOUTL
Pre-speaker AC Output Left Channel
O
(1) See databyte specification - speaker attenuators
Pin type legenda:
I = Input
O = Output
I/O = Input/Output
S = Supply
TDA7461N
3/31
AUDIO PROCESSOR PART
Input Multiplexer
Fully differential or quasi-differential CD and
cassette stereo input
AM mono or stereo input
Phone differential or single ended input
Internal beep with 2 frequencies (selectable)
Mixable phone and beep signals
Loudness
Second order frequency response
Programmable center frequency and quality factor
15 x 1dB steps
Selectable flat-mode (constant attenuation)
Volume control
1dB attenuator
Max. gain 20dB
Max. attenuation 79dB
Soft-step gain control
Bass Control
2nd order frequency response
Center frequency programmable in 4(5) steps
DC gain programmable
7 x 2dB steps
Treble Control
2nd order frequency response
Center frequency programmable in 4 steps
7 x 2dB steps
Speaker Control
4 independent speaker controls (1dB steps
control range 50dB)
Mute Functions
Direct mute
Digitally controlled softmute with 4 program-
mable time constants
ELECTRICAL CHARACTERISTICS (V
S
= 9V; T
amb
= 25
C; R
L
= 10K
; all gains = 0dB; f = 1KHz;
unless otherwise specified).
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
INPUT SELECTOR
R
in
Input Resistance
all inputs except Phone
70
100
130
K
V
CL
Clipping Level
2.2
2.6
V
RMS
S
IN
Input Separation
80
100
dB
G
IN MIN
Min. Input Gain
-1
0
1
dB
G
IN MAX
Max. Input Gain
13
14
15
dB
G
STEP
Step Resolution
1
2
3
dB
V
DC
DC Steps
Adjacent Gain Step
-5
0
+5
mV
G
MIN
to G
MAX
-5
1
+5
mV
DIFFERENTIAL CD STEREO INPUT
R
in
Input Resistance
Differential
70
100
130
K
Common Mode
20
30
40
K
CMRR
Common Mode Rejection Ratio
V
CM
= 1
VRMS
@ 1KHz
45
70
dB
V
CM
= 1
VRMS
@ 10KHz
45
60
dB
e
N
Output Noise @ Speaker
Output
20Hz to 20KHz flat; all stages
0dB
9
15
V
DIFFERENTIAL PHONE INPUT
R
in
Input Resistance
Differential
10
15
20
K
Common Mode
20
30
40
K
CMRR
Common Mode Rejection Ratio
V
CM
= 1
VRMS
@ 1KHz
45
70
dB
V
CM
= 1
VRMS
@ 10KHz
45
60
dB
TDA7461N
4/31
ELECTRICAL CHARACTERISTICS (continued)
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
BEEP CONTROL
V
RMS
Beep Level
250
350
500
mV
f
BMIN
Lower Beep Frequency
570
600
630
Hz
f
BMAX
Higher Beep Frequency
1.15
1.2
1.25
KHz
MIXING CONTROL
M
LEVEL
Mixing Level
Source
-1
0
1
dB
Source
-5
-6
-7
dB
Source
-10
-12
-14
dB
Beep/Phone
-1
0
1
dB
VOLUME CONTROL
G
MAX
Max Gain
19
20
21
dB
A
MAX
Max Attenuation
-83
-79
-75
dB
A
STEP
Step Resolution
0.5
1
1.5
dB
E
A
Attenuation Set Error
G = -20 to 20dB
-1.25
0
1.25
dB
G = -60 to 20dB
-4
0
3
dB
E
T
Tracking Error
2
dB
V
DC
DC Steps
Adjacent Attenuation Steps
-3
0.1
3
mV
From 0dB to G
MIN
-7
0.5
+7
mV
LOUDNESS CONTROL
A
STEP
Step Resolution
0.5
1
1.5
dB
A
MAX
Max. Attenuation
-16
-15
-14
dB
f
CMIN
Lower Center Frequency
180
200
220
Hz
f
CMAX
Higher Center Frequency
360
400
440
Hz
SOFT MUTE
A
MUTE
Mute Attenuation
60
100
dB
T
D
Delay Time
T1
0.48
1
ms
T2
0.96
2
ms
T3
20
40.4
60
ms
T4
200
324
600
ms
V
THlow
Low Threshold for SM Pin
1
1
V
V
THhigh
High Threshold for SM Pin
2.5
V
R
PU
Internal Pull-up Resistor
70
100
130
K
V
PU
Pull-up Voltage
4.7
V
SOFT STEP
T
SW
Switch Time
5
10
15
ms
1) The SM pin is active low (Mute = 0)
TDA7461N
5/31
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