Siemens TDA5950X Datasheet

Video and Sound IF with FM-PLL
Demodulator, AFC and V & S SCART

Features

● Features video and sound IF

● Video and sound SCART

● AFC

● NTSC option

TDA 5950X

Bipolar IC

P-DSO-24-1

Type Ordering Code Package

TDA 5950X Q67000-A5112 P-DSO-24-1 (SMD)
TDA 5950X Q67007-A5112 P-DSO-24-1 Tape and Reel dry

Functional Description

Video IF Section

Video IF-broadband amplifier followed by a quasi-synchronous demodulator for negative
modulated IF signals. A video switch interface is included in the video section. A separate video
output after the demodulator permits the installation of one or more sound traps at the input of the
video switch. The tuner AGC threshold is set by means of a potentiometer, all other functions can
switched with open collector transistors.

Sound IF Section

FM-IF limiter with FM-PLL demodulator for the frequency range of 5.5 MHz to 6.5 MHz. The AF
section includes an audio switch followed by an audio buffer output.

Application

The TDA 5950X is suitable for application in television receivers or video tape recorders with A/V
switches.

Semiconductor Group 1 12.94

TDA 5950X

Circuit Description
Video IF Section

The video IF section incorporates a four-stage, capacitively coupled, symmetrical and controlled
amplifier, a limiter with selection and a mixer for quasi-synchronous demodulation of negative
modulated IF signals followed by a video output amplifier. The video demodulator output and the
video switch input are connected by means of a sound trap. The video switch has two inputs (for
signals from video demodulator and from external source) and two outputs. Parallel to the video
output amplifier the video signal is used for generating the AGC voltage. The control circuit is
designed on the integralaction AGC principle, employing a noise-free peak value detector. A
delayed tuner AGC voltage with positive control direction is derived from the AGC voltage via a
threshold amplifier that is set by means of an external potentiometer. An AFC push pull output
current is generated from picture carrier tank circuit.

Sound IF Section

The sound IF section incorporates a five-stage, symmetrical limiter amplifier followed by a PLL
demodulator. The AF section contains an audio switch followed by an output buffer.

Switch Matrix
AUX/RF-Control

(Pin 4)

0 0 muted
01IF
1 0 muted
1 1 SCART

AV-OFF
(Pin 17)

Output
(Pin 8 / Pin 19)

Semiconductor Group 2

Pin Functions
Pin No. Function

1 Delayed tuner AGC output
2 Delayed tuner AGC threshold
3 AGC-time constant
4 Aux / RF control
5 Ground

TDA 5950X

6+
7 Auxiliary video output
8 Video output
9 Auxiliary video input
10 AFC output
11 Demodulator tank circuit
12 Demodulator tank circuit
13 Video input at sound trap output
14 Video demodulator output
15 Sound IF ground
16 Sound IF input
17 A / V OFF
18 Auxiliary audio input
19 Audio output
20 Auxiliary audio output
21 De-emphasis capacitor

V

supply voltage

S

22 Low-pass capacitor
23 Video IF input
24 Video IF input

Semiconductor Group 3

TDA 5950X

Block Diagram

Semiconductor Group 4