TDA4483
TELEFUNKEN Semiconductors
Rev. A1, 15-May-96
1 (8)
Intercarrier Mixer and AM-Demodulator for TV and VCR
Features
D Very high input sensitivity
D Excellent signal-to-noise ratio
D Intercarrier output signal gain controlled and indepen-
dent from the picture carrier to sound carrier ratio
D AM demodulator alignment free
D Few external components
D ESD protected
Case: DIP14
Block Diagram
1
2
4
5
6
14
13
12
10
8
IF Input
sound carrier
IF Input
picture carrier
+V
S
AF output
(AM)
Standard switch
(AM / FM)
Intercarrier
output (FM)
7
AGC
93 7481
Figure 1.
TDA4483
TELEFUNKEN Semiconductors
Rev. A1, 15-May-96
2 (8)
Pin Description
Pin
Function
1, 2
IF input (sound carrier)
3, 9, 11
No connected
4, 13
Ground
5, 6
IF input (picture carrier)
7
AGC time constant
8
Intercarrier output
10
Standard switch
12
AF output (AM)
14
Supply voltage
1
2
3
4
5
6
7
8
14
13
12
11
10
9
Circuit Description
The bipolar circuit TDA4483 enables high quality sound
IF processing for multistandard applications in TV-sets
and VCR. This circuit has separate inputs for the sound-
and picture carrier. The sound carrier signal (single or
dual carrier, modulated with AM, FM or NICAM) from
the SAW filter will be fed into a 3-stage, gain controlled,
IF amplifier (Pin 1 and 2).
The following two mixer stages operate using different
standards. In the case of AM, the first mixer works as a
quasi-synchronous detector providing the audio
frequency at Pin 12. Furthermore, the first mixer supplies
a regulation voltage to control the gain of the 3-stage IF
amplifier (AGC).
The second mixer stage works as a intercarrier mixer in
FM/NICAM mode and supplies the intercarrier signal at
Pin 8 (difference signal between picture and sound
carrier) independent of the picture carrier to sound carrier
ratio. In standard B/G the 5.5/5.74 MHz subcarrier is
available at Pin 8. The required picture carrier for the
intercarrier mixer will be coupled out from the tuned
demodulator circuit of the vision-IF IC (e.g. TDA4453 or
equivalent components). The selective and prelimited
picture carrier has to be applied symmetrically to the
picture carrier input (Pin 5 and Pin 6). An additional
limiting amplifier delivers the regenerated picture carrier
to the intercarrier mixer.
Possible modes of operation (FM/NICAM or AM) are
determined by the voltage level that is applied to Pin 10
(standard switch). Without external control voltage at
Pin
10, the FM/NICAM operation is automatically
selected. In the case of AM, the intercarrier output Pin 8
is switched off, however DC output voltage remains. In
corresponding with FM/NICAM operation, the AF output
Pin 12 is switched off.
TDA4483
TELEFUNKEN Semiconductors
Rev. A1, 15-May-96
3 (8)
Absolute Maximum Ratings
Reference point Pin 13 (4), unless otherwise specified.
Parameters
Symbol
Value
Unit
Supply voltage
Pin 14
V
S
13.5
V
Supply current
Pin 14
I
S
50
mA
Power dissipation
P
tot
680
mW
Junction temperature
T
j
125
C
Operating temperature, ambient
T
amb
25 to +70
C
Storage temperature
T
stg
25 to +125
C
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction-ambient
R
thJA
90
K/W
Electrical Characteristics
T
amb
= 25
C, V
S
= 12 V, reference point: Pin 13 (4), unless otherwise specified
Parameters
Test Conditions / Pins
Symbol
Min.
Typ.
Max.
Unit
Supply voltage range
Pin 14
V
S
10
13.5
V
Supply current
FM-mode
Pin 14
AM-mode
I
S
37
32
mA
DC output voltage
Pin 8
Pin 12
V
O
3.6
3.2
V
Standard switch
Pin 10
Control voltage
Internal voltage FM-mode
automatically selected
AM-mode
FM-mode
Pin 10 open
V
CTRL
0
2.2
2.3
1.5
V
S
V
Control current
V
CTRL
t
5 V
Pin 10
I
CTRL
200
mA
FM-mode
Test conditions: Picture carrier f
PC
= 38.9 MHz, sound carrier f
SC1
= 33.4 MHz, f
SC2
= 33.1587 MHz,
picture carrier to sound carriers ratio = 13/20 dB, picture carrier unmodulated (equivalent to sync peak pulse)
Sound carrier frequency range
f
SC
30
40
MHz
Picture carrier input voltage
Pin 5, 6
v
PC
10
20
30
mV
Sound carrier minimal
input voltage
5.5 MHz intercarrier
signal 3 dB
Pin 1, 2
v
SC
50
mV
Sound carrier gain control
range
AGC
60
65
dB
Intercarrier output voltage
Pin 8
v
OIC
350
mV
Output resistance
Pin 8
R
O
15
W
Signal to noise ratio
Test conditions: Sound carrier V
SC
= 10 mV, picture carrier v
PC
= 20 mV, limited carrier from TDA4453 or com-
parable vision IF circuit, reference signal: frequency deviation
f =
30 kHz, sound modulation f
mod
=
1 kHz.
Weighted (S + N)/N ratio of the demodulated intercarrier signal in accordance with CCIR468-4, measured with
FM-demodulator U2829B
Picture carrier unmodulated
Channel 1/2
(S + N)/N
68/67
dB
Black picture
Channel 1/2
(S + N)/N
62/60
dB
Grid
Channel 1/2
(S + N)/N
50/48
dB
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