Philips TDA3567 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA3567

NTSC decoder

Product speciﬁcation File under Integrated Circuits, IC02

June 1986

Philips Semiconductors Product speciﬁcation

NTSC decoder TDA3567

GENERAL DESCRIPTION

The TDA3567 is a monolithic integrated decoder for the NTSC colour television standards. It combines all functions required for the demodulation of NTSC signals. Further more it contains a luminance amplifier, an RGB-matrix and amplifier. These amplifiers supply output signals up to 5 V peak-to-peak (picture information) enabling direct drive of the discrete output stages.

QUICK REFERENCE DATA

PARAMETER CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

Supply voltage pin 1 VP=V Supply current pin 1 I

Luminance input signal

pin 8

1-17

P=I1

Input voltage

(peak-to-peak value) V

8-17(p-p)

Contrast control range − 20 − dB

Chrominance ampliﬁer

pin 3

Input voltage

(peak-to-peak value) V

3-17(p-p)

Saturation control range 50 −−dB

9 12 13,2 V

− 65 − mA

− 0,45 − V

− 550 − mV

RGB matrix and ampliﬁers

Output voltage at nominal

luminance input signal and nominal contrast (peak-to-peak value) V

Sandcastle input

pin 7

Blanking input voltage V

10,11,12-17(p-p)

7-17

4,0 5,0 6,0 V

1,0 1,5 2,0 V

Burst gating and clamping

input voltage V

7-17(p-p)

6,5 7,0 7,5 V

PACKAGE OUTLINE

18-lead DIL; plastic, with internal heatspreader (SOT102-1); SOT102-1; 1996 November 25.

June 1986 2

Philips Semiconductors Product speciﬁcation

NTSC decoder TDA3567

June 1986 3

Fig.1 Block diagram.

Philips Semiconductors Product speciﬁcation

NTSC decoder TDA3567

FUNCTIONAL DESCRIPTION Luminance ampliﬁer

(1)

The luminance amplifier is voltage driven and requires an input signal of 450 mV peak-to-peak line must be connected between the i.f. amplifier and the decoder. The input signal must be a.c. coupled to the input pin 8.

The black level clamp circuit of the RGB amplifiers uses the coupling capacitor as a storage capacitor. After clamping the signal is fed to a peaking stage. The RC network connected to pin 13 is used to define the amount of overshoot.

The peaking stage is followed by a contrast control stage. The control voltage has to be supplied to pin 6. The control voltage range is nominally −17 to + 3 dB. The linear curve of the contrast control voltage is shown in Fig.2.

Chrominance ampliﬁer

The chrominance amplifier has an asymmetrical input. The input signal at pin 3 must be a.c. coupled, and must have an amplitude of 550 mV peak-to-peak. The gain control stage has a control range in excess of 30 dB, the maximum input signal should not exceed 1,1 V peak-to-peak, otherwise clipping of the input signal will occur. From the gain control stage the chrominance signal is fed to the saturation and contrast control stages. Chrominance and luminance control stages are directly coupled to obtain good tracking. The saturation is linearly controlled via pin 5. The control voltage range is 2 V to 4 V. The impedance is high and the saturation control range is in excess of 50 dB. The burst signal is not affected by contrast or saturation control. After the amplification and control stages the chrominance signal is internally fed to the (R-Y) and (B-Y) demodulators, burst phase and a.c.c. detectors.

The luminance delay

Oscillator and a.c.c. circuit

The 3,58 MHz reference oscillator operates at the subcarrier frequency. The crystal must be connected between pin 16 and ground. The oscillator does not require adjustment due to the small spreads of the IC. The free running frequency of the oscillator can be checked by connecting the saturation control (pin 5) to the positive supply line. Then the loop is opened, so that the frequency can be measured. The oscillator has an internal gain limiting stage which controls the gain to unity, so that internal signals are sinusoidal. This prevents the generation of higher harmonics of the subcarrier signals. The burst signal is compared to a 0° reference signal by the burst amplitude detector and is then amplified and fed to a peak detector for a.c.c. and to a sample and hold circuit which drives the colour killer circuit. The reference signal for the burst phase detector is provided by the 90° phase shifted signal. An RC network is used to obtain the required catching range and noise immunity for the output voltage of the burst phase detector.

The hue control is obtained by mixing oscillator signals with a phase of 0° and 90° before they are fed to the (R-Y) and (B-Y) demodulators. The 90°phase shifted signal is provided by a miller integrator (biased by pin 18). As the hue control is independent of the PLL, the control will react without time delay on the control voltage changes.

Demodulator circuits

The demodulators are driven by the amplified and controlled chrominance signals, the reference signals are obtained from the hue control circuit. In nominal hue control position the phase angle of (R-Y) reference signal is 0°, the phase angle of the (B-Y) reference signal is 90°.

For flesh tone corrections the demodulated (R-Y) signal is matrixed with the demodulated (B-Y) signal according to the following equations:

RY–()

matrixed

GY–()

matrixed

161R Y–()IN0– 42 B Y–()

,,=

043R Y–()IN0– 11 B Y–()

,,=

BY–()

matrixed

(1) Signal with negative going sync; amplitude includes sync pulse amplitude.

BY–()

June 1986 4

Philips Semiconductors Product speciﬁcation

NTSC decoder TDA3567

In these equations (R-Y)IN and (B-Y)IN indicate the colour difference signal amplitudes, when the chrominance signal is demodulated with a phase difference between the R-Y and B-Y demodulator of 90° and a gain ratio B-Y/R-Y = 1,78.

RGB matrix circuit and ampliﬁers

The three matrix and amplifier circuits are identical. The luminance signal and the colour difference signals are added in the matrix circuit to obtain the colour signal.

Output signals are 5 V (peak-to-peak) (black-white) for the following nominal input signals and control settings.

• Luminance 450 mV (peak-to-peak)

• Chrominance 550 mV (peak-to-peak) (burst-to-chrominance ratio of the input 1 : 2.2)

• Contrast −3 dB (maximum)

• Saturation −10 dB (maximum)

The maximum available output voltage is approximately 7 V (peak-to-peak). The black level of the red channel is compared with a variable external reference level (pin 9), which provides the brightness control. The control loop is closed via the luminance input.

The luminance input is varied to control the black level control, therefore the green and blue outputs will follow any variation of the red output. The output of the black control can be varied between 2 V to 4 V. The corresponding brightness control voltage is shown in Fig.4.

If the output signal surpasses the level of 9 V the peak-white limiter circuit becomes active and reduces the output signal via the contrast control.

Blanking of RGB signals

A slicing level of about 1,5 V is used for this blanking function, so that the wide part of the sandcastle pulse is separated from the rest of the pulse. During blanking a level of + 2 V is available at the output.

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