TDA5931-65 Datasheet, PDF (1/13 Pages) Siemens Semiconductor Group – Video IF Amplifier and Demodulator with Full-SCART

Video IF Amplifier and Demodulator
with Full-SCART
Features
q Multistandard video IF
q Interference suppression circuitry
q Mean/peak value control
q Area of application: TV set with Full-SCART
TDA 5931-65
Bipolar IC
P-DIP-18
Type
TDA 5931-65
Ordering Code
Q67000-A5136
Package
P-DIP-18
Functional Description
Video IF for all European standards for positive and negative modulation. The video section
contains a Full-SCART interface. An output for the demodulated video signal (pin 9) allows the
insertion of a sound trap into the signal path to the input or the SCART switch and the SCART output
buffer amplifier (pin 7). The analog setting function (delayed AGC threshold) is controlled via a
potentiometer, all other switch functions are controlled via open-collector transistors.
Circuit Description
The component includes a four-stage, capacitively coupled, symmetrically designed and controlled
amplifier, a limiter with selection, and a mixer for quasi-synchronous demodulation of positive and
negative modulated IF signals. In addition a video output amplifier and noise suppression circuitry
are included. This output is used for generating the AGC voltage. The AGC for both modulation
types has been realized as integral AGC with noise free peak and mean value detector (only for
positive modulation). For SCART applications this output is switched a video source switch with two
inputs (for the demodulator signal or SCART socket) and two outputs (SCART- and TV output). The
demodulator output (pin 9) provides a video signal output level 3 dB higher than the level required
for the operation of the TV set or to drive the SCART connector. Therefore it is possible to insert a
sound trap in between this output and the input of the SCART switch (pin 7). The insertion loss of
the sound trap has to attenuate the signal level at pin 9 by a factor 2/3 or 3 dB (AC and DC) to avoid
distortions in the SCART switch.
The delayed tuner AGC is generated by a threshold amplifier driven by the control voltage. The
amplifier response can be controlled by means of an external potentiometer. (The increase of the
tuner AGC voltage shall create a higher tuner gain = positive control).
Semiconductor Group
31
06.94