Philips TDA3853T Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA3853T

TV IF amplifier and demodulator with TV-identification

Preliminary speciﬁcation File under Integrated Circuits, IC02

January 1992

Philips Semiconductors Preliminary speciﬁcation

TV IF ampliﬁer and demodulator with

TDA3853T

TV-identiﬁcation

FEATURES

• Suitable for standards B/G (I, M, N, DK), see Table 1

• Gain controlled 3-stage IF amplifier with typically

80 MHz bandwidth

• High performance synchronous demodulator for negative and positive video modulation; passive regeneration of the reference signal

• Peak-sync-related AGC

• AGC output voltage take over point adjustable

• High sensitive TV identification based on vertical pulse

duty cycle recognition; IDENT output

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

supply voltage 4.75 5 6 V supply current − 46 − mA vision IF input signal sensitivity (RMS value, pins 1-20) − 70 100 µV maximum vision IF input signal (RMS value, pins 1-20) 100 −−mV

o CVBS

IF gain control range 63 66 − dB

buffered CVBS output signal on pin 12 (peak-to-peak value) 1.7 2 2.3 V B −3 dB video bandwidth (pin 12) − 14 − MHz S/N signal-to-noise ratio for video 55 60 − dB

1.1

3.3

spur

amb

intermodulation attenuation at yellow 53 56 − dB

suppression of spurious harmonics of video signal 22 26 − dB

operating ambient temperature 0 − 70 °C

• Video off switch

• Sound trap buffer amplifier

• Tracking generator (AFT output) with Q-demodulator

and internal 90 degree phase shifter for tracking the reference circuit

• Low supply voltage 5 V, low power consumption

GENERAL DESCRIPTION

Monolithic integrated circuit for vision IF signal processing in TV and VTR sets.

60 −−dB

ORDERING INFORMATION

EXTENDED

TYPE NUMBER

PINS PIN POSITION MATERIAL CODE

PACKAGE

TDA3853T 20 mini-pack plastic SOT163A

Note

1. SOT163-1; 1997 January 8.

January 1992 2

Philips Semiconductors Preliminary speciﬁcation

TV IF ampliﬁer and demodulator with TV-identiﬁcation

TDA3853T

Fig.1 Block diagram.

January 1992 3

Philips Semiconductors Preliminary speciﬁcation

TV IF ampliﬁer and demodulator with TV-identiﬁcation

PINNING

SYMBOL PIN DESCRIPTION

i a

TOP 2 tuner AGC take over adjustment point (TOP) C

n.c. 4 not connected VIDOFF 5 video off input, identiﬁcation capacitor IDENT 6 TV identiﬁcation output TRSW 7 set input for tracking switch, tracking hold capacitor AFT 8 automatic frequency tracking output n.c. 9 not connected RES1 10 resonance reference circuit for vision carrier RES2 11 resonance reference circuit for vision carrier CVBS 12 CVBS output (positive) TRAP 13 video buffer ampliﬁer input from sound trap VIDEO 14 video and sound intercarrier output V

stab

GND 17 ground (0 V) C

AGC

AGC 19 AGC output to tuner V

i b

1 balanced vision IF input a

3 capacitor for black level

15 +5 V supply voltage 16 decoupling capacitor for voltage stabilizer

18 capacitor for AGC

20 balanced vision IF input b

TDA3853T

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION

The TDA3853T is a TV IF amplifier/demodulator for negative modulation.

The IF input signal is amplified, gain-controlled and demodulated (Fig.1).

Vision IF ampliﬁer and demodulator

The vision IF amplifier consists of three AC-coupled differential amplifiers. Gain control is achieved by current divider stages. Emitter feedback resistors in the differential amplifiers are optimized with respect to noise and signal capability.

Synchronous demodulator

The demodulator has a reference amplifier consisting of a differential

amplifier with resistive load to provide passive vision carrier regeneration. This allows capacitive coupling of the resonance circuit to obtain a notch filter characteristic and tracking of the resonance circuit. A cascaded limiter amplifier follows the reference amplifier to eliminate amplitude modulation. The limited IF reference signal is fed to the demodulator. The unlimited IF signal is fed via a phase correction network to the demodulator. The video amplifier is an operational amplifier with a wide bandwidth and internal feedback. The video and sound intercarrier signal is output on pin 14.

Video buffer ampliﬁer

This operational amplifier has a wide bandwidth with internal feedback and frequency compensation. Gain and input impedance are adapted to

operate with a ceramic sound trap. The switching functions are described in Table 1.

AGC detector and IF gain control

The video signal is fed through low-pass filters to attenuate the sound carriers and then is fed to the AGC detector.

Peak-sync AGC detection. A special network provides current pulses to fast charge the AGC capacitor on pin 18 (gain reduction). This achieves a minimum of video distortion. The AGC control converts the AGC capacitor voltage to three separate voltages to control the IF stages.

January 1992 4

Philips Semiconductors Preliminary speciﬁcation

TV IF ampliﬁer and demodulator with TV-identiﬁcation

Sync pulse separator

The sync pulse separator separates the composite sync signal to gate the AFT. The vertical sync is used for identification. The input is band-limited to obtain a higher ident sensitivity.

Table 1 Switching functions of TDA3853T.

VIDOFF

PIN 5

pin L L setting 2.2 µFL

Note

1. capacitor on pin 7 means tracking active; LOW means tracking inactive

Tuner AGC

Tracking generator (AFT)

(1) (1)

TRSW

PIN 7

video OFF 0.5 mA sink video ON H or 0.5 mA sink

VIDEO

SIGNAL

TDA3853T

IDENT

PIN 6

The tuner AGC output current is fed to the open-collector output on pin 19. The take-over point is adjusted externally at pin 2 to adapt the tuner and SAW filter to an optimum IF input level. The IF gain variation over the full tuner gain range (slip) is minimized to ensure a constant tuner output signal.

Identiﬁcation

An analog integrating network followed by a window comparator identifies the video signal by detection of the duty cycle of the vertical sync pulses. The pulses charge the identification capacitor on pin 5.

A limited 90 degree phase-shifted vision carrier signal is fed to the AFT quadrature demodulator, internal RC networks provide active phase shifting. The linear IF signal is applied to the other AFT quadrature demodulator input. The AFT output signal is applied to a gating stage. Gating with the composite sync pulses activates the AFT demodulator. Therefore the AFT output is free from video modulation. The AFT capacitor (pin 7) is charged by the gated AFT current. The capacitor voltage is converted to an DC output current on pin 9 (open-collector sink/source currents).

January 1992 5

Philips Semiconductors Preliminary speciﬁcation

TV IF ampliﬁer and demodulator with

TDA3853T

TV-identiﬁcation

LIMITING VALUES

In accordance with the Absolute Maximum System (IEC 134).

SYMBOL PARAMETER MIN. MAX. UNIT

5,7

2,16

5,6

stg

amb

ESD

supply voltage 0 6.0 V supply current on pin 15 − 55 mA voltage on pins 6, 8 and 12 −0.3 V

voltage on pins 5 and 7 −0.3 5.5 V voltage on pin 13 −0.3 5.0 V voltage on pin 14 −0.3 4.2 V voltage on pin 19 −0.3 13.2 V current on pins 2 and 16 −−200 µA current on pins 5 and 6 −−60 µA current on pin 7 −−100 µA current on pin 8 −−50 µA current on pin 12 −−10 mA current on pin 14 −−3mA storage temperature range −25 +150 °C operating ambient temperature range 0 +70 °C electrostatic handling

(1)

for all pins

(2)

−±300 V

Notes

1. Equivalent to discharging a 200 pF capacitor through a 0 Ω series resistor.

2. Pins 1, 10, 11 and 20 have special protection, the other pins have standard protection by diodes to V (this excludes pins 15 (VP) and 19 (tuner AGC output) which have standard protection to GND only).

and GND

January 1992 6

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