TDA7420
MULTIFUNCTION AUDIO PROCESSOR
CASSETTE PREAMPLIFIER:
FORWARD/REVERSE
INPUTS
GROUND
COMPATIBLE
INTERNAL SWITCHES FOR EQUALIZATION
INTERNAL ADJUSTMENT FOR TRAKING
INTERNAL ADJUSTMENT FOR OUTPUT
AMS:
INPUT GAIN CONTROL
ADJUSTABLE GAIN VERSUS FREQUENCY
AUDIOPROCESSOR:
INPUTS: 1 FULLY DIFFERENTIAL, 1 DIFFER-
ENTIAL, 1 STEREO AND 1 MONO
INPUT GAIN FROM 0 TO 15dB (1dB STEP)
VOLUME CONTROL FROM +16 TO -63dB
(1dB STEP)
BASS AND TREBLE CONTROL FROM -18
TO 18dB (1dB STEP)
DIRECT MUTE, SOFT MUTE AND RADIO
MUTE
FOUR INDEPENDENT OUTPUT STAGES:
- ATTENUATION CONTROL FROM
0 TO -79dB (1dB STEP)
- BEEP CONTROL (ON/OFF, FRONT/REAR)
STEREO DECODER:
ROLL-OFF ADJUSTMENT
SELECTABLE DEEMPHASIS
19KHz CANCELLATION
HIGH CUT CONTROL
STEREO BLEND
NOISE BLANKER
AUTOMATIC THRESHOLD CONTROL AND
PROGRAMMABLE TRIGGER THRESHOLD
INTEGRATED HIGH PASS FILTER
PACKAGE: TQFP64 (14x14)
DESCRIPTION
The TDA7420 I
2
C bus controlled multifunction
audio processor contains all signal processing
blocks of a high performance car radio, including
audioprocessor, stereodecoder, noise blanker,
different mute functions, cassette preamplifier and
AMS function.
The use of BICMOS technology allows the imple-
mentation of several filter functions with switched
capacitor techniques like fully integrated, adjust-
ment free PLL Loop filter, pilot detector with inte-
grator.
This minimizes the number of external compo-
nents.
Due to a highly linear signal processing, using
CMOS-switching techniques instead of standard
bipolar multipliers, very low distortion and very
low noise are obtained also in the stereodecoder
part.
Very low DC stepping is obtained by use of the
BICMOS technology.
May 1998
ORDERING NUMBER: TDA7420
TQFP 64 (14x14)
1/29
ELECTRICAL CHARACTERISTICS (V
S
= 8.5V; T
amb
= 25
C; R
L
= 10K
; all gains = 0dB; f = 1KHz;
unless otherwise specified, refer to the Test Circuit.)
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
INPUT SECTION
Differential Input Pins 52, 53, 54, 55
R
I
Input Resistance
37
50
63
K
V
CL
Clipping Level
THD = 0.3%
2.0
2.5
Vrms
CMRR
Common Mode Rejection Ratio
45
55
dB
G
DIFF
Differential Gain
-1
0
1
dB
Stereo Input Pins 56, 57
R
I
Input Resistance
75
100
125
K
V
CL
Clipping Level
2.0
2.5
Vrms
Quasi Differential Input Pins 58, 59,60
R
I
Input Resistance
18
25
32
K
V
CL
Clipping Level
2.0
2.5
Vrms
Composite Input Pin 61
R
I
Input Resistance
18
25
32
K
V
CL
Clipping Level
2.0
2.5
Vrms
MULTIPLEXER
R
O
Output Resistance (pin 2,3)
100
200
300
G
IMIN
Minimum Gain
-1
0
1
dB
G
IMAX
Maximum Gain
14
15
16
dB
G
STEP
Step Resolution
0.5
1
1.5
dB
V
DC
Dc Steps
Adjacent Gain Step
-5
1
5
mV
G
MIN
to G
MAX
2
mV
VOLUME CONTROL
R
I
Input Resistance (1, 64)
24
33
42
K
C
MAX
Max Gain
15
16
17
dB
A
MAX
Max Attenuation
63
dB
A
STEPC
Step Resolution Coarse
Attenuation
A
V
= 16 to -40dB
0.5
1.0
1.5
dB
E
A
Attenuation Set Error
G =16 to -40dB
-1.5
0
1.5
dB
E
T
Tracking Error
2
dB
V
DC
DC Steps
Adjacent Attenuation Steps
-3
0.1
3
mV
from 0dB to A
MAX
0.5
5
mV
SOFT MUTE
A
MUTE
Mute Attenuation
40
50
dB
t
D
Delay Time
C
EXT
= 22nF;
I = I
MAX
0 to -20dB;
I = I
MIN
1.0
ms
23
ms
BASS CONTROL
C
RANGE
Control Range
+15
+18
+20
dB
A
STEP
Step Resolution
0.5
1
1.5
dB
R
B
Internal Feedback Resistance
48
65
82
K
TDA7420
4/29
ELECTRICAL CHARACTERISTICS (continued.)
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
TREBLE CONTROL
C
RANGE
Control Range
+17
+18
+19
dB
A
STEP
Step Resolution
0.5
1
1.5
dB
R
T
Internal Feedback Resistance
37
50
63
K
SPEAKER ATTENUATORS
C
RANGE
Control Range
79
dB
A
STEP
Step Resolution
A
V
= 0 to -40dB
0.5
1
1.5
dB
A
MUTE
Output Mute Attenuation
80
100
dB
E
A
Attenuation Set Error
A
V
= 0 to -40dB
1.50
dB
V
DC
DC Step
Adjacent Attenuation Steps
0.1
3
mV
AUDIO OUTPUTS
V
CLIP
Clipping Level
d = 0.3%
2.0
2.5
V
RMS
R
L
Output Load Resistance
2
K
R
OUT
Output Impedance
100
200
300
V
DC
DC Voltage Level
3.35
3.6
3.85
V
GENERAL
E
NO
Output Noise
BW = 20Hz to 20KHz, flat
Output Muted
All gains = 0dB
4.0
5.0
15
V
V
S/N
Signal to Noise Ratio
All gains 0dB; V
O
= 1V
RMS
;
106
dB
d
Distortion
V
I
= 1V
RMS
;
0.01
0.08
%
S
C
Channel Separation Left/Right
80
95
dB
E
T
Total Tracking Error
A
V
= 0 to -20dB;
0
1
dB
A
V
= -20 to -40dB;
0
2
dB
BUS INPUT
V
IL
Input Low Voltage
1
V
V
IH
Input High Voltage
3
V
I
IN
Input Current
V
IN
= 0.4V
-5
5
A
V
O
Output Voltage SDA
Acknowledge
I
O
= 1.6mA
0.1
0.4
V
SUPPLY
V
IL
Supply Voltage
6.5
8.5
10.0
V
I
S
Supply Current
Stereo Decoder = ON
25
33
41
mA
Stereo Decoder = OFF
20
28
35
mA
SVR
Ripple Rejection
C
ref
= 22
F
Audioprocessor
80
dB
Stereo Decoder + Audioprocessor
60
dB
TDA7420
5/29
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