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TDA9725

Y/C automatic adjustment processor (VHS standard)

Philips Electronics 

Philips Semiconductors

Y/C automatic adjustment processor

(VHS standard)

Product specification

TDA9725

FUNCTIONAL DESCRIPTION

Record (REC)/electric to electric (EE) mode

LUMINANCE

From input pin 43 the CVBS signal is fed via the automatic

gain control (AGC) and subclamp (SCL) to the output

pin 41. Instead of the controlled and clamped CVBS signal

it is also possible to switch (dependent on the level at

pin 42) white, black or sync-level to this pin. To eliminate

chrominance parts the CVBS signal is fed to the luminance

low-pass filter (YLPF) and to the sync separator stage.

The sync signal is available at pin 45. The signal is also fed

via vertical emphasis non-linear emphasis (NLE),

deviation control stage, main emphasis and white-dark clip

to the FM modulator. The FM signal is available at pin 11.

CHROMINANCE

The chrominance signal is selected out of CVBS (from

pin 43) in BPF 4.43 MHz (band-pass filter) and controlled

in automatic chrominance control (ACC).

The chrominance signal is mixed with 5.06 MHz to

627 kHz and via LPF 627 kHz to the output pin 30.

Playback (PB)/video to video (VV) mode

LUMINANCE

The FM signal is fed via FM AGC and double limiter to the

controlled FM demodulator. After demodulation and

filtering in sub low-pass filter (SUBLPF) main

de-emphasis, YLPF and non-linear de-emphasis the

signal is fed to the vertical noise reduction (YNR) and in

parallel to the sync separator. The chrominance signal is

added in the Y/C mixer. The complete CVBS signal is

available at pin 41.

CHROMINANCE

The 627 kHz chrominance signal coming from tape via

BPF 627 kHz and field ACC to the balanced mixer. Mixed

with 5.06 MHz the 4.43 MHz chrominance signal is fed via

comb driver stage to the external comb filter (pin 35) and

via internal conjugated complex (C*) stage and internal AC

coupling to the luminance part.

Record and playback

In both modes record (REC) and playback (PB) the

5.06 MHz mixer frequency is produced by the 20.24 MHz

voltage controlled oscillator (VCO) and a divide-by-four.

LIMITING VALUES

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

SYMBOL

VCC

VI

Vn

II

Ptot

Tstg

Tamb

Ves

PARAMETER

supply voltage

input voltage at pin 22

input voltage on all other pins

input current at pin 22

total power dissipation

storage temperature

operating ambient temperature

electrostatic handling for all pins

CONDITIONS

note 1

MIN.

0

0

0

−

−

−25

−20

−300

TYP.

−

−

−

−

−

−

−

−

Note

1. Charge device model class B: discharging a 200 pF capacitor via a 0 Ω series resistor.

MAX.

6.0

1.6

VCC

10

1 250

+150

+70

+300

UNIT

V

V

V

mA

mW

°C

°C

V

THERMAL CHARACTERISTICS

SYMBOL

Rth j-a

PARAMETER

thermal resistance from junction to ambient in free air

VALUE

43

UNIT

K/W

1996 Oct 14

7

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