Teac EU-34T - Page 12

10
CF72416
TELETEXT
GENERAL DESCRIPTION
The CF72416 is a new device comparable with the currently available CF72306 but having the added capability of
extracting Video Programming System (VPS) data. The CF72416 forms the Analogue component of the texas
Instruments (TI) teletext system.
The device performans the functions of composite sync separation and both teletext and VPS data extraction and
clock regeneration from the recevied video signal and passes clock, data and composite sync to the digital decoder chip.
The same pins are used for either teletext or VPS data and are identified by the appropriate decoder.
The CF72416 device has the following features and enhancements over the CF72306:-
(a) VPS data decoding.
(b) Improved adaptive slicing level for the Sync seperator and sync noise information added to composite sync
which when used with Texas Instruments Multipage and Eurotext decoders gives improved locking performance.
(c) Minor board changes are required to upgrade to the CF72416 from the CF72306.
The crystal oscillator is the same as used with the CF72306. The crystal specification is given below:-
13.875MHZ Crystal Specificatýon
- Oscillation Mode ....................................................................... Fundamental Parallel
- Frequency ................................................................................ 13.8750 MHz
- Crystal Frequency Stability ....................................................... ± 150ppm *
- Maximum Crystal ESR (steady-state) ....................................... 60 Ohms
- Maximum Crystal ESR (start-up) .............................................. 120 Ohms
- Maximum Shunt Capacitance................................................... 7 pF
- Maximum Motional Capacitance............................................... 30 fF
- Crystal Load Capacitance......................................................... 18 pF
- Free Air Operating Temperature Range.................................... 0 to 70 º C
- Drive Level ............................................................................... 1 mW max.
- Ageing ...................................................................................... ± 5 ppm max for first year
* Includes temperature stability and manufacturing tolerance.
FEATURES
n Extracts both Teletext and VPS data
n Forms a custom 2-chip solution when used with an ASICTEXT decoder
n Low power 1µm CMOS (<100mW)
n Standard 20 pin/300mll package.
n Tolerates a range of výdeo distortions
n Operates with 13.875 MHz fundamental mode crystal.
PINNING
1- TSIG Výdeo Sync Reference
2- SSIG Výdeo Sync Input
3- SSIG Výdeo Data Input
4- AGND1 Analogue Ground
5- OSC1 13.875 MHz Oscilator
6- OSC2 13.875 MHz Oscilator
7- AVCC Analogue Vcc
8- CREF Video Data Reference Input
9- AGND2 Analogue Ground
10- BIAS Internal Reference
11- TSTAPLB Test/Application
12- TCLK Teletext Clock
13- TDATA Teletext Data
14- DGND2 Digital Ground
15- OSCOUT Oscillator Output
16- DVCC Digital Vcc
17- WIND Timing Signal
18- DGND1 Digital Ground
19- SYNC Separated Sync Output
21- TEXTSEL Sync Noise Select Note 1
Signal pins = 14 Power pins = 6