M491B

SINGLE-CHIP VOLTAGE SYNTHESIS TUNING SYSTEM

WITH 1 ANALOG CONTROL

September 1992

.

16-STATION MEMORY - 7-SEGMENT LED

DISPLAY

.

VOLTAGE SYNTHESIZER : 13 BITS

.

4-BAND PRESET CAPABILITY

.

NON-VOLATILE MEMORY : 304 BITS

- 16 WORDS OF 19 BITS FOR TUNING VOLT-

AGE (13 bits) - BAND (2 bits) - FINE DETUN-

ING (4 bits)

- 10

- MIN 10 YEARS DATA RETENTION

.

PCM REMOTE CONTROL RECEIVER : DE-

CODES SIGNAL TRANSMITTED BY M708

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VOLUME D/A : 6-BIT RESOLUTION / 8kHz

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MEMORY SKIP FUNCTION

.

AUTOMATIC SEARCH WITH DIGITAL AFT

CONTROL

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FINE DETUNING D/A ACTING ON AFT DIS-

CRIMINATOR (16 steps) WITH SEPARATE

STORAGE FOR EACH MEMORY POSITION.

ALTERNATIVELY IT CAN BE USED TO CON-

TROL BRIGHTNESS OR COLOUR SATURA-

TION

.

MANUAL SEARCH WITH DIGITAL AFT CON-

TROL

.

MANUAL SEARCH WITH LINEAR AFT

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SWEEP SEARCH DISPLAY OUTPUT

.

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CLOCK OSCILLATOR : 445 TO 510kHz

.

INTEGRATED DIGITAL POWER ON RESET

(no external initialization circuitry required)

DIP40

(Plastic Package)

ORDER CODE : M491B1

DESCRIPTION

The M491B is a monolithic N-MOS LSI circuit in-

cluding a Floating-gate Non-Volatile Memory for

storage of up to 16 stations. Tuning of the station

is performed with a 8192 step D/A converter, using

the principle of voltage synthesis. It is designed for

7-segment LED displays. Direct memory selection

is possible only from remote control while Up/Down

memory scanning is possible on the set and also

from remote control. An option input for 8 or 16

stations is available. The circuit also includes a

PCM remote control receiver operating in conjunc-

tion with the transmitter M708. The highly reliable

transmission code ensures error-free signal detec-

tion even in presence of high noise conditions.

Search of the station is possible in automatic or

manual modes. The circuit can operate with a

Digital or Linear AFT control. The Digital AFT mode

is necessary for automatic search and requires an

external circuit (TDA4433 or equivalent, e.g. dual

comparator plus TV station detector) to convert the

AFC-S-curve into an Up/Down command. Fine tun-

ing (detuning) is also possible with different modes

of operation. The circuit is assembled in 40-pindual

in-line plastic package.

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40

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25

13

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24

23

22

21

(GND)

MEMORY SUPPLY

MEMORY TIMING

FINE TUNING D/A

TUNING D/A

DIGITAL AFT STATUS

OSC. IN

OSC. OUT

TEST

AFT 1

AFT 2

SWEEP DISPLAY OUT

VOLUME D/A

DIGITAL AFT EN.

V3

V2

V1

X4

X3

X2

X1

MAINS ON OPTION

MAINSON/OFF

SEGM. a

SEGM. b

SEGM.c

SEGM. d

OPT. 8/16

SEGM. e

SEGM.f

SEGM. g

SEGM.h + i

UHF

CATV

VHF III

VHF I

V

S S

V

DD

V

SS

(GND)

LINEAR AFT DEF.

I.R. INPUT

PIN CONNECTIONS

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