TDA4474 Datasheet, PDF (5/17 Pages) TEMIC Semiconductors – Multistandard Video-IF and Quasi Parallel Sound Processing

TELEFUNKEN Semiconductors
TDA4474
SIF amplifier output is multiplied in phase with the
limited SIF signal (AM is removed). The AF signal of the
demodulator output is fed to the output amplifier and to
the SIF–AGC. For all TV standards with negative video
modulation (e.g. B/G standard) the AF output signal
(Pin 27) is switched off by the standard switch.
Quasi–Parallel–Sound (QPS) mixer
The QPS mixer is realized by a multiplier. The SIF signal
(FM or NICAM carrier) is converted to the intercarrier
frequency by the regenerated picture carrier (quadrature
signal) which is provided from the VCO. The intercarrier
signal is fed via an output amplifier to Pin 26.
Standard Switch
To have equal polarity of the video output signal the
polarity can be switched in the demodulation stage in
accordance with the TV standard. Additional a standard
dependent DC level shift in the video amplifier delievers
the same sync level. Parallel the correct VIF–AGC is
selected for positive or negative modulated VIF signals.
In case of negative modulation (e.g. B/G standard) the
AM output signal is switched off. If the standard for
positive modulation (L standard) is selected the AM
demodulator and QPS mixer is active. This condition
allows a parallel operation of the AM sound signal and the
NICAM–L stereo sound.
L’ Switch and VIF Input Selection
For positive modulated signals (L/L’ standard) Pin 16
works as L’ switch. With a control voltage the VCO
frequency can be switched for setting to the required
L’ value (L’ standard). Also a fine adjustment of the
L’-VCO centre frequency is possible by a potentiometer.
The L’ switch is only active for positive modulated video
IF signals (standard switch in L mode). In this mode the
video IF input 2 (VIF2) is forced by the standard switch.
The possibility to select VIF1 input is given by
connecting VIF2 input (Pin 10 or 11) via 10 k resistor to
ground.
If negative modulation (B/G mode) is selected pin 16 op-
erates as an input selection switch for the two VIF inputs.
AFC Switch
The AFC output signal at Pin 24 can be controlled by a
switching voltage at Pin 21. It is possible to select an AFC
output signal with rising– or falling AFC curve and to
switch off the AFC.
Internal Voltage Stabilizer
The internal bandgap reference ensures constant
performance independant of supply voltage and
temperature.
Absolute maximum values
Reference point pin 4 (9, 18), unless otherwise specified
Parameters
ÁÁÁ _{Supply voltage}
Pin 25
ÁÁÁÁ ÁÁ _{Supply current}
Pin 25
ÁÁÁÁ ÁÁ _{Power dissipation, Vs = + 9 V}
ÁÁÁÁÁÁÁ _{Output currents}
Pin 14 26, 27
ÁÁÁÁ ÁÁÁ _{External voltages}
Pins 1, 2, 5–8, 10–12,
ÁÁÁSymbol
V_s
I_s
P
Á^Iout
V_ext
14, 16, 19, 20, 26–30
ÁÁÁÁÁÁÁÁÁÁ ^{Junction temperature}
Storage temperature
Electrostatic handling *)
ÁÁ _ÁÁÁ ^{Pins 17, 22, 23}
Pin 13
Pins 3, 15, 21, 24
all pins
ÁÁ^Tjunc
T_stor
V_ESD
*) Equivalent to discharging a 200 pF capacitor through a 0 resistor
ÁÁÁValue
90
Á85
765
5
+ 4.5
Á^{+ 3.5}
+ 13 5
ÁÁ^Vs
+125
25 to +125
300
Operating Range
Á ÁÁÁ ^{ÁÁÁ Parameters}
Supply voltage range
Pin 25
Ambient temperature
ÁSymbol
V_s
T_amb
Value
Á ^{4 5 to 9 0}
0 to +85
Rev. A1: 17.08.1995
Preliminary Information
Á^Unit
ÁÁÁ^V
mA
mW
mA
V
V
V
V
°C
°C
V
Unit
V
°C
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