TDA8349 データシートの表示（PDF） - Philips Electronics
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TDA8349 Datasheet PDF : 17 Pages
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Philips Semiconductors
Multistandard IF amplifier and demodulator
Product specification
TDA8349A
This sample-and-hold circuit is not used in the L mode, but
it will function as a low-pass filter in this mode and
therefore also reduces the video dependency of the AFC.
A gain stage amplifies the voltage swing by 5 times. The
output of the AFC circuit will be an inverse analog output
on pin 8 when pin 9 is connected to a voltage above 8 V. If
pin 9 is connected to a voltage above 10 V the output will
be a normal analog output. Normally pins 8 and 9 together
provide digital AFC information.
Video recognition circuit
For full scart functions it is necessary to implement a
second mute function for non-video signals in the whole
television concept. This is realized in this IF-IC. With an
internal sync separator and an internal integrator it is
possible to achieve a very sensitive identification circuit,
which measures the mean frequency of the input signal.
This is normally approximately 16 kHz. The integrator
capacitor will be loaded during the whole line time and
unloaded during the sync pulse. The maximum voltage at
this internal capacitor is a value for the main frequency of
the video signal. By changing the value of an external
capacitor it is possible to influence the speed and
sensitivity of the recognition circuit. It is possible to gain
sensitivity performance at disturbed signals by increasing
the value of the external capacitor, however this will
reduce the speed of the identification circuit.
Video switch circuit
The video switch also provides application for full SCART
functions. The circuit has two inputs, one output and a
control pin. The switch selects either internal or external
video signals. A × 2 gain stage for the external input
provides an equal output level for internal or external video
from the SCART. The crosstalk of the unwanted signal is
better than −50 dB and the total signal handling meets all
the requirements for SCART specifications.
LIMITING VALUES
In accordance with the Absolute Maximum System (IEC 134)
SYMBOL
PARAMETER
V14-17
Ptot
Tstg
Tamb
supply voltage (pin 14)
total power dissipation
storage temperature range
operating ambient temperature range
MIN.
−0.5
−
−25
−25
MAX.
13.2
1.2
+150
+ 75
UNIT
V
W
°C
°C
February 1991
6
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