Assessments - 3, GPA: 4.7
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For a complete black and white receiver only the output stages for video, sound, horizontal and vertical deflection and a tuner have to be added. The TDA8303 is for applications with npn tuners and the TDA8303A for pnp tuners. FUNCTIONAL DESCRIPTION Video IF amplifier, demodulator and video amplifier Each of the three AC-coupled IF stages permits the omission of DC feedback and possesses a control range in excess of 20 dB. An additional advantage is the symmetry of the amplifier which results in a less critical application. ORDERING INFORMATION The IF amplifier is followed by a passive synchronous demodulator providing a regenerated carrier signal. This is limited by a logarithmic limiter circuit prior to its application to the demodulator. The limiter has a very low differential phase shift which results in good differential gain and phase figures. The video amplifier also contains a white spot inverter and a noise clamp which limits interference pulses to a point below the peak sync level. This circuit is more effective than a noise inverter and results in an improved picture stability, with respect to interference. AFC-circuit The reference signal for the AFC circuit is obtained from the demodulator tuned circuit. In this way only one tuned circuit needs to be applied and only one adjustment has to be carried out. The disadvantage with this method is that the frequency spectrum of the signal fed to the detector is determined by the SAW filter characteristic. This spectrum is asymmetrical with respect to the picture carrier so that the AFC output voltage is dependent on the video signal. To overcome this video frequency dependency of the AFC output, the demodulator output is followed by a sample-and-hold circuit which samples during the sync level of the signal. This means that only the carrier signal is available to the AFC and it will not be affected by the video information. At very weak input signals the drive signal of the AFC circuit will contain substantial noise. This noise has an asymmetrical frequency spectrum causing an offset in the AFC output voltage. This effect can be minimized by applying a notch in the demodulator tuned circuit. The sample-and-hold circuit is followed by an amplifier with high output impedance, therefore the steepness of the of the AFC control voltage is dependent on the load impedance. EXTENDED TYPE PACKAGE NUMBER PINS PIN POSITION MATERIAL CODE TDA8303 28 DIL plastic SOT117(1) TDA8303A 28 DIL plastic SOT117(1) Note 1. SOT117-1; 1996 December 3. July 1992 2 Philips Semiconductors Preliminary specification TDA8303 Small signal combination IC for black/white TV TDA8303A QUICK REFERENCE DATA SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT Supply VP positive supply voltage (pin 7) 9.5 12 13.2 V IP supply current (pin 7) 90 125 160 mA Istart start current (pin 11) note 1 - 6.5 9 mA Video V8-9(RMS) IF sensitivity (RMS value) at 38.9 MHz; note 2 20 40 65 mV G8-9 IF gain control range - 74 - dB S/N signal-to-noise ratio input signal = 10 mV - 57 - dB V18(p-p) AFC output voltage swing (peak-to-peak value) 10.5 - 11.5 V Sound V12(RMS) AF output signal (RMS value) note 3 400 600 800 mV AMS AM suppression at VI = 50 mV - 58 - dB THD total harmonic distortion - 0.5 - % Sync V25 required sync pulse amplitude note 4 200 - - mV I27 required input current during flyback pulse 0.1 - 2 mA V22 coincidence detector output voltage in synchronized condition in no signal condition - - 9.7 1.5 - - V V V22 vertical feedback for DC voltage 2.9 3.3 3.7 V V22(p-p) vertical feedback for AC voltage (peak-to-peak value) - 1.2 - V Notes to the quick reference data 1. Pin 11 has a double function. When during switch-on a current of 9 mA is supplied to this pin, it is used to start the horizontal oscillator. The main supply can then be obtained from the horizontal deflection stage. When no current is supplied to this pin it can be used as a volume control. 2. On set AGC. 3. The output signal is measured at Df = 7.5 kHz and maximum volume control. 4. The minimum value is obtained by connecting a 1.8 kW resistor and a 470 nF capacitor in series between the video output and pin 25. The slicing level can be varied by changing the value of this resistor (higher resistance value results in a larger value of the minimum sync pulse amplitude). The slicing level is independent of the video information. July 1992 3 Philips Semiconductors Philips Semiconductors Small signal combination IC for black/white TDA8303 TV TDA8303A Fig.1 Block diagram July 1992 4 Philips Semiconductors Philips Semiconductors Small signal combination IC for black/white TDA8303 TV TDA8303A PINNING PIN DESCRIPTION 1 AGC take-over 2 vertical ramp generator 3 vertical drive 4 vertical feedback 5 tuner AGC 6 ground 7 supply voltage input 8 video IF input 9 video IF input 10 IF AGC 11 volume control/start horizontal oscillator 12 audio output 13 sound demodulator 14 sound IF decoupling 15 sound IF input 16 ground (for some critical parts) 17 video...
Este manual também é adequado para os modelos :TV - TDA8303A (125.87 kb)