M491B Datasheet, PDF (1/16 Pages) STMicroelectronics – SINGLE-CHIP VOLTAGE SYNTHESIS TUNING SYSTEM WITH 1 ANALOG CONTROL

M491B
SINGLE-CHIP VOLTAGE SYNTHESIS TUNING SYSTEM
WITH 1 ANALOG CONTROL
. 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)
- 10⁴ MODIFY CYCLES PER WORD
- MIN 10 YEARS DATA RETENTION
. PCM REMOTE CONTROL RECEIVER : DE-
CODES SIGNAL TRANSMITTED BY M708
. _{VOLUME D/A : 6-BIT RESOLUTION / 8kHz}
. _{MEMORY SKIP FUNCTION}
. _{AUTOMATIC SEARCH WITH DIGITAL AFT}
CONTROL
. 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}
. _{SWEEP SEARCH DISPLAY OUTPUT}
. _{SUPPLY VOLTAGES : VDD = + 5V,}
V_PP = + 25V FOR THE MEMORY
. _{CLOCK OSCILLATOR : 445 TO 510kHz}
. _{INTEGRATED DIGITAL POWER ON RESET}
(no external initialization circuitry required)
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.
DIP40
(Plastic Package)
ORDER CODE : M491B1
PIN CONNECTIONS
V_SS (GND)
1
MEMORY SUPPLY
2
MEMORY TIMING
3
FINE TUNING D/A
4
TUNING D/A
5
DIGITAL AFT STATUS
6
OSC. IN
7
OSC. OUT
8
V_DD
9
TEST
10
I.R. INPUT
11
AFT 1
12
AFT 2
13
SWEEP DISPLAY OUT
14
VOLUME D/A
15
LINEAR AFT DEF.
16
DIGITAL AFT EN.
17
V3
18
V2
19
V1
20
40
VHF I
39
VHF III
38
CATV
37
UHF
36
SEGM.h + i
35
SEGM. g
34
SEGM. f
33
SEGM. e
32
V_SS (GND)
31
OPT. 8/16
30
SEGM. d
29
SEGM. c
28
SEGM. b
27
SEGM. a
26
MAINS ON/OFF
25
MAINS ON OPTION
24
X1
23
X2
22
X3
21
X4
September 1992
1/16