SGS-THOMSON M494 Technical data

查询M494供应商

SINGLE-CHIPVOLTAGE TUNING SYSTEM WITH

4 ANALOGCONTROLS AND µP INTERFACE

.

NON-VOLATILE MEMORY FOR 20 PRO­GRAMWORDS (17 BIT x 20)

- TUNINGVOLTAGE12BITS

- BAND2 BITS

- MULTI STANDARD 2 BITS

- PROGRAMSKIP BIT 1 BIT

- 10,000MODIFY CYCLESPER WORD

- MIN.10 YEARSDATARETENTION

.

13 BITVOLTAGESYNTHESIZER(BRM + PWM)

.

NV MEMORY FOR 4 ANALOG CONTROLS
(6 BITx 4)

.

4 BANDSWITCH OUTPUTS
(VHF I & III, UHF, CATV)

.

5 x 7 KEYBOARD

.

2 AUDIOVISUAL OUTPUTS (VCR& PC)

.

2 CODED MULTI STANDARD OUTPUTS
(e.g. PAL, SECAM, NTSC etc.)

.

DIRECT 11/2 DIGIT 7 SEGMENT COMMON
ANODE LED DISPLAYDRIVING

.

PCMREMOTE CONTROL RECEIVER
(M708 transmitter)

.

5-BIT DATA INPUT + CONTROL LINE FOR
P INTERFACE

.

LINEARAFC DEFEATOUTPUT

.

FLYBACK/SYNC.COINCIDENCE INPUTFOR
SEMI-AUTOMATICSEARCH

.

STANDBY OUTPUT

.

OPTIONSELECT : 16 OR 20 PROGRAMS

.

POWERUP MODE

.

PROGRAMSKIP DEFEAT

.

AVOPTIONS

.

1 * OR DECADE MODE OPTION IN 20 PRO­GRAM OPTION

.

TEMPORARY ANALOG UP/DOWN INDICA­TOR ON LED DISPLAY

.

BANDSKIP OPTION

.

455 TO 510kHz CHEAP CERAMIC RESONATOR

.

VDD=5V ±5%. VPP= 25V ± 1V

M494

pable of including a floatinggate NV memorycell
(EEPROM).

The i.c. has been designed as a complete digital
TV tuning system based on the voltage synthesis
principleand as a replacementfor all the conven­tional potentiometers and band switches particu­larly in low cost TV sets. It also provides some
functionsnormallyonlyassociatedwithhighercost
sets.NV memoryis integratedonthe chip together
withallthenecessarycontrolcircuitrytoprovidethe
program memory. Separate NV memory is also
integrated to provide the memory for four analog
controls. A seven segment LED display can be
directly driven by the chip to display the program
selected, and the direction of movement of the
analog controls. Provision is made for a remote
control receiver both on and off chip, the latter is
interfacedvia a data input and single controlline.
(Thisenablescontrol by a microprocessor).Alocal
keyboardcan be used with the device in avariety
of configurations.An optionselect pinprovides for
different program number options, power up op­tionsand skip associated functions. This device is
anothersignificantstep towards the completeinte­gration of TV control circuitry.

The device is packaged in a 40 pin DIL plastic
package.

DIP40

(Plastic Package)

DESCRIPTION

The M494 is a monolithic LSI integrated circuit
fabricatedinSGS-THOMSON’sEPM2process; an
N-channel, Planox, doublepoly MOS process ca-

June 1991

ORDER CODE : M494B1

1/22

M494

PINCONNECTIONS

OPTION SELECT

DISPLAY DRIVE

h+i

V

AV0
AV1

V

MEMORYTIMING

1

D4

2

D3

3

D2

4

D1

5

D0

6
7
8
9

g

10

f

11

e

12

SS

13

d

14

c

15

b

16

a

17
18
19

PP

20

DATA HANDSHAKE

40

V

39

DD

STANDBY

38

AFC DEFEAT

37

FB/SYNC COINCIDENCE

36

REMOTECONTROL

35

VOLUME

34

SATURATION

33

TEST 1

32

BRIGHTNESS

31

MS0

30

MS1

29

CONTRAST

28

TUNING

27

OSC. OUT

26

OSC. IN

25

VHF 1

24

VHF 3

23

CATV

22

UHF

21

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

V

DD

V

PP

V

V

O(off)

I

OL

t

PD

P

tot

T

stg

T

op

C

os

R

os

C

dk

R

k

C

rts

Stresses above those under ”Absolute Maximum Ratings” may causes permanent damage to the device. This is a stress rating only and
functional operation of the device at theseor any other conditions above those indicated in the operational sections of this specification is not
implied. Exposure to absolute maximum rating conditions for extended periodsmay affect device reliability.

Supply Voltage – 0.3 to 7 V
Memory Supply Voltage – 0.3 to 26 V
Input Voltage – 0.3 to 15 V

I

Off State Input Voltage 15 V
Output Low Current

LED Driver Outputs : pin a-g

pin h + i

All other Outputs

20
35

5
Max. Delaybetween Memory Timing & Memory Supply Pulses 5 µs
Total Package Power Dissipation 1 W
Storage Temperature – 25 to + 125 °C
Operating Temperature 0 to + 70 °C
Capacitance on OptionSelect Pin 100 pF
Resistance on Option Select Pin 1 kΩ
Capacitance on data outputs & keyboard inputs when lines are

150 pF

connected by a keyboard switch closure
Series Resistance of Single Keyboard Switch 10 kΩ
Capacitance on Data Handshake Pin 50 pF

mA
mA
mA

494-01.EPS

494-01.TBL

2/22

M494

STATICELECTRICAL CHARACTERISTICS (T

Pins Symbol Parameter Test Conditions Min. Typ. Max. Unit

Memory Supply I

Memory Timing V

I

O(off)

Tuning V
V

DD

I
RC V
FB/sync. Coin. Input V

V

Vol. Brigh. Sat.
Contr. DACs

V

I

O(off)

h+i V

V

V

D0, D1
D2, D3
D4

V

V

V

I

O(off)

MS0, MS1 AFC
def. AV0, AV1

V

I

O(off)

Option Select V

V

Standby V

a, b, c, d, e, f, g V

V

V

Display Drive V

I

O(off)

UHF, III, I, CATV V

V

V

V

I

O(off)

Data
Handshake

V
V

V

V

I

O(off)

Memory Supply

PP

Current

R Pull Down 25 kΩ

OL

Leakage VDD= 4.75V, VO= 26V 100 µA

OL

Supply Current VDD= 5.25V 100 mA

DD

pk to pk 0.5 13.2 V

I
IL
IH

I

IL

R Pull up 30 kΩ

OL

IL
IH

I

IL

R Pull up 200 kΩ

OH

IL
IH

I

IL
OL

R Pull up 30 KΩ

OL

IL
IH

I

IL

R Pull up 30 kΩ

OL

I

O

IL
IH

I

IL

R Pull up 200 kΩ

OL
OL

OL
OH

IL
IH

OL
OH

IL
IH

I

IL

R Pull up 30 kΩ

=0to70°C, VDD= 5V unless otherwisespecified)

amb

VPP= 25V Write Peak

Write Average
Erase Peak
Erase Average
Read Peak
Read Average

VDD= 4.75V, IOL= 2.5mA 8 V

VDD= 4.75V, IOL= 5mA 1 V

2.0 V

VDD= 5.25V, VIL= 0.8V – 0.4 mA

VDD= 4.75V, IOL= 4mA 1 V
VDD= 5.25V, VO= 13.2V 50 µA

3.5 V

VDD= 5.25V, VIL= 1.5V – 50 µA

VDD= 4.75V, IOL= 30mA 1.5 V

3.5 V
VDD= 5.25V, VIL= 1.5V – 0.4 mA
VDD= 4.75V, IOL= 1mA 0.4 V
V

= 5.5V 25 µA

O(off)

VDD= 4.75V, IOL= 1mA 0.4 V
VDD= 5.25V, VO13.2V 50 µA

3.5 V
VDD= 5.25V, VIL= 1.5V – 0.4 mA

VDD= 4.75V, IOL= 100µA 0.4 V
VDD= 4.75V, VO= 0.7V 1.6 mA

3.5 V
VDD= 5.25V, VIL= 1.5V – 50 µA

VDD= 4.75V, IOL= 15mA 1.5 V
VDD= 4.75V, IOL= 5mA 0.4 V
VDD= 5.25V, VO= 13.2V 50 µA
VDD= 4.75V, IOL= 1mA 3 V
VDD= 4.75V, IOH= – 150µA 2.4 V

3.5 V
VDD= 5.25V, VO= 13.2V 50 µA
VDD= 4.75V, IOL= 1mA 3 V
VDD= 4.75V, IOH= 150µA 2.4 V

3.5 V
VDD= 5.25V, VIL= 1.5V – 0.4 mA

VDD= 5.25V, VO= 13.2V 50 µA

35

mA

10

mA

9

mA

5

mA

8

mA

2.5

mA

0.8 V

1.5 V

1.5 V

1.5 V

1.5 V

1.5 V

1.5 V

494-02.TBL

3/22

M494

DEFINITIONOF TERMS

The M494 has four conditions or statesthat it can
be in which are defined below. Logic LO 0V and
logic HI = 5V.

PoweredDown

V

=0V.VPP=0V

DD

On

=5V.VPP=25V.

V

DD

Devicedriving display normally.
Data Handshake pinconfigured as RTSi/p.
Standby o/p = HI. All other functions operating
normally.

Standby

=5V.VPP=0V.

V

DD

Device driving display to show a singlestatic bar
(g segment).

FUNCTIONAL DESCRIPTION (clock frequency = 500kHz)
V

DD&VSS

VDD=+5V± 5%.Whenapplied,an internalpower
onresetof110msisgenerated.Thevoltagethresh­old for the reset is in the range 3 to 3.5V but is in
fact the point at which the internal clock phases
start.

V

=0V.This pin is connectedto the substrate of

SS

the i.c. and is the reference for all parameters of
the device.

Oscillator I/O

The frequencyof the oscillator should be between
445 and 510kHz using a cheap ceramicresonator.
The reference frequency of the remote control
transmitter must also be in the same range i.e. if
the oscillator frequency is 455kHz then the trans­mitter frequencycouldbe 510kHzor viceversa.

Test

Thispinis normallyusedforpost fabricationtesting
purposesonly andshould betied to V

. However

SS

this pin can be used by SGS-THOMSON or the
OEM to enable external loading of the memory.
Details of how to achieve this can be furnishedby
SGS-THOMSON.

DataHandshakepinconfiguredasRTS i/p.Stanby
o/p =LO.
All keyboard commands are disabled except any
programcommand On/Off, On/Stanby.
Memory sequence up or down, 1 * and ±10 (dec­ade) commands.
Analog controls. Tuning, AV, MS and AFC defeat
o/p’s = LO. Band o/p’s= HI (externallypulled up).
See Standby section for more detail.

Off

V

DD

Data Handshakepin configuredas OFF o/p.
Standby o/p = LO. Display disabled and Display
driveo/p = HI (externallypulled up).
All keyboard commandsdisabled except ON/OFF.
Remoteand data command sources disabled.
Analog controls, Tuning, AV, MS and AFC defeat
o/p’s = HI (externallypulled up).

The signal from the preamplifier (TDA8160) is
broughtto the RC signal input via an AC coupling
network(seeFigure 1).

Figure1

The input is self biased to approx. 1.5V. When a
largesignal is applied to the input a levelshift will
take place predominantlydue to the coupling net­work.

Howeveranother time constantis alsovisible due
to the coupling C and the internal resistorR
Figures. 2 & 3).

Figure2

=5V.VPP= 0V. Device not driving display.

VDD(TDA8160) R C

5V 2.2kΩ 4.7nF

12V 10kΩ 4.7nF

TDA8160

RC

M494

. (see

i

V

DD

494-02.EPS

Remote ControlInput

The integratedRCreceiver decodessignalstrans­mitted by the M708 (address 10). The minimum
signal amplitude should be 0.5V peak to peak at
the input pin. The minimum pulse width should be
8µs.

4/22

1.5V

Ri

to Cct

Remote
ControlI/P

494-03.EPS

FUNCTIONAL DESCRIPTION (continued)
Figure 3

τ

=RC

1

τ

=Ri.C

2

1.5V

Severaltests are performedon the signal :
a) Measurement of the pulse distance T (time

base synchronization).

b) Check of the bit positions relative to the time

basewindows.
c) Checkof theparity bit.
d) Check oftheabsenceof pulsesbetweenparity

and stop pulses.
e) Check of the noise level. The receiver checks

the noise level for a time T after each pulse

detected.
If all these tests are successful the received word

is stored and decoded. If not it is rejected. The
transmissionis terminatedon receptionof the end
of transmission (EOT) code or if the internal timer
measuresatransmission interruptionof morethan
550ms. For more detail concerning the operation
of theRC receiver refer toSGS-THOMSON Tech­nical Note No. 155 pp11-12.

The RC receiverand the local keyboardhave the
same command source priority i.e. a local com­mand is not accepted until a previously accepted
RC commandhas been completelyexecuted and
the EOTcode transmitted. Similarly if alocalcom­mand isunder executionthenan RCcommandwill
not be accepted. The RC truth table and com­mandsare shownon the next page.

Analog Control Outputs

Four analog control outputs are implemented to
provide for Volume, Brightness, Saturation and
Contrast from four 6 bit D/A’s. TheseD/A’suse the
Pulse Width Modulation technique to synthesize a
pulse trainof constantfrequencybut variablepulse
width (PWM). Each output delivers a 7.8kHz
square wave whose duty cycle is variable in 63
steps. External RC filtering and level shifting is
required to realise a static DC voltage from the
pulse train. If the analog outputs are continuously
varied by command from the keyboard or data
commandsourcesthe outputswill change approx.
every 112ms (fck = 500kHz) or approx. every
102ms if the command is issued from the RC
command source. One analog control is specifi-

callydesignedasa volumecontrolas mutecircuitry
isbuilt in.

On start up resetthe analogcontrol outputs except
volume are enabled after a period of approx.

1.1 seconds. In the Standbyand Off statesall the
analogcontrol outputs arepulled to logicLO.

The normalise command reads the contents of
each analog memory sequentially to its corre-

494-04.EPS

spondingcounter and D/Aoutput.

Tuning Output

The tuning voltage is generated from a 13 bit
counter.Theprogrammemorystoresthe 12MSB’s
of the tuning word. The range of the AFC circuitry
is at least 3 bits so the LSB of the tuning counter
doesnot affectthe resolutionof tuning.

Thecontents of the counterare convertedusing a
PWM and a Bit Rate Multiplier (BRM) technique.
13 bits gives 8192 steps which yields a resolution
ofapproximately3.9mVwith a max. tuning voltage
of 32V. This corresponds to a resolution of about
75kHzin the UHF band. The 5 MSB’sof thetuning
word areconverted using PWM and the remaining
8 bits using BRM. Thus as the tuning word in­creasesfromall zeroesthenumberof pulsesinone
period increases to 256 with all the pulses being
the same length (t

=2µs). Forvalues larger then

o

256 PWM conversiontakes placewhere the num­ber of pulses in one period stays constant at 256
but the width changes.

Whenthepulsewidth reaches15t

twosuccessive

o

pulses ”link” together and the number of pulses
decreases(see Figure 4).

Thepulse trainis fed toan externallow pass filter
to realise a DC voltage. The temperaturedepend­ence of thissystem is predominantlythe switching
times of the output pulses and asthere are only a
maximumof256 pulsesin oneperiodthetempera­turestability is very good.

InStandbyand Offstatesthetuningoutputispulled
to logic LO.

Figure4

No OF PULSES

256

TUNING

1V 31V

VOLTAGE

M494

494-05.EPS

5/22

M494

FUNCTIONAL DESCRIPTION (continued)
Table1 : RemoteControl Commands(address 10, code =1010)

Command

Number

0
1
2
3
4
5
6

7
8

9
10
11
12

13
14
15
16
17
18

19
20
21
22
23
24

25
26
27
29
28
30

The above table showns the differencebetween the 16 and 20 program optionswith respect to the remote control commands. Commands 16,
17, 18 &21 change function between the two options. Commands 22, 23 & 24 should not be used in the 20 program option, as theyhave no
function.
NOP = No operation

16 Programs 20 Programs C1 C2 C3 C4 C5 C6

EOT
Standby
Mute (toggle)
Program 1
Program 2
Program 3
Program 4

Contrast up
Contrast down
Program 5
Program 6
Program 7
Program 8

Memory Seq. up
Memory Seq. down
Program 9
Program 10
Program 11
Program 12

Normalise
On/stby (tog.)
Program 13
Program 14
Program 15
Program 16

Volume up
Volume down
Brightness up
Brightness down
Saturation up
Saturation down

Function Code

EOT
Standby
Mute (toggle)
Program 1
Program 2
Program 3
Program 4

Contrast up
Contrast down
Program 5
Program 6
Program 7
Program 8

Memory Seq. up
Memory Seq. down
Program 9
Program 0
– 10 (decade)
+ 10 (decade)

Normalise
On/stby (tog.)
1*
NOP
NOP
NOP

Volume up
Volume down
Brightness up
Brightness down
Saturation up
Saturation down

0
1
1
0
1
0
1

1
1
0
1
0
1

1
1
0
1
0
1

1
1
0
1
0
1

1
1
0
0
1
1

0
0
1
0
0
1
1

0
1
0
0
1
1

0
1
0
0
1
1

0
1
0
0
1
1

0
1
0
1
0
1

0
0
0
1
1
1
1

0
0
1
1
1
1

0
0
1
1
1
1

0
0
1
1
1
1

0
0
1
1
1
1

0
0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
0
0
0

1
1
1
1
1
1

0
0
0
0
0
0
0

1
1
1
1
1
1

0
0
0
0
0
0

1
1
1
1
1
1

1
1
1
1
1
1

0
0
0
0
0
0
0

0
0
0
0
0
0

1
1
1
1
1
1

1
1
1
1
1
1

1
1
1
1
1
1

Program Memory

NV memory(EEPROM)is integratedon thechipto
provide storage for up to20 stations.
Each memorylocationis 17 bits inlengthproviding
12 bits fortuning voltage,2 bits for band, 2 bits for
two coded multi-standard outputs and 1 bit pro­gram skipflag.
Individualprogramwordscanbe readoncommand
from the keyboard, remote or data command
sources but can only be written oncommandfrom
the keyboard.
There are twomethods for storing a program(writ­ing the memory): pre and post tuning selectionof
the programnumber. See Commands, section7.
Readingeach memory locationin sequence(up or
down) can also beachievedfromall thecommand
sources.

All memory timing functionsare provided on chip
and only one external transistor is required to
switch the external memory supply (25V).

6/22

Thereare essentiallytwo operationscarriedouton
the memory: Write/Modifyand Read.
The Write/Modifycycle consistsof 3 steps :

a) All ”1s” are written to thebits of theaddressed

word.
b) All bits of the word are erased.
c) The new contents are written.

Usingthismethodallthebitsof theaddressedword
are aged thesame.Formore detail concerningthe
write, erase and read current waveforms at the
Memory Supplypin seeM491 datasheet.

MemoryFor Analog Controls

The memory for the analog controls is electrically
identicaltothemain programmemory butis organ­ised as four 6-bit words located in two sequentially
addressed words at the memory. Each word cor­responds to the Volume, Brightness, Saturation
and Contrast outputs. At power on reset and nor­malise commandeachmemory word is readout to
its corresponding counterand D/Ain sequence.

FUNCTIONAL DESCRIPTION (continued)
Display,Keyboard and Data Multiplexing

Logic is integrated on the chip to provide the mul­tiplexing between the display, keyboard and data
inputs. In the On state and with the Data Hand­shake pin at logic HI as an input the display and
keyboardare muxed together.See Figure 5. Each
column output goes to logicLO in sequence and
the row inputs are scanned for a key closure. In
chronological order across the total mux. period
there is : initialisation, scan, decision and display
periods.

The Data Handshake pin has a complex logical
function. It hastwo modesof operation: as a hand
shake I/O line to a µP and as an output line to the
P to signalthat theM494is in theOff state.In order
to achieve this function careful signal timing is
required both internally and externallyto the chip.
See Figure6. Whenthe deviceis in the OFFstate
the Data Handshake pin is used to signal this
condition to theµP by being pulled LO.

Figure 6 : Data-input-timing

Figure5

D0

D1

D2

D3

D4

DISPLAY
DRIVE

( 2ms)

INITIALIZE

MUX PERIOD (8ms)

640µs

SCAN

DECISION

M494

DISPLAY

494-06.EPS

A1 B1 C1 D1 A2 B2 C2 D2 A3

DATA
HANDSHAKE

D0 - D4

EOE
(END OF TRANSMISSION)

DATA HANDSHAKE

NOT TO SCALE

PIN CONFIGURATION

N° Symbol Parameter Min. Typ. Max. Unit

1t

RTS

2t

CTS

3t

O/P

4t

HS

5t
6t
7t
8t

Note : Oscillator Clock = 500kHz

S
H

J

CR

t

CR

t

O/P

t

RTS

t

j

t

CTS

DATA DATA

t

t

HS

t

t

S

CTS

H

t

CR

t

O/P

K/B AND RC I/P
DISABLEDTILL
EOT EXECYTION

(EOT = END OF

O/II/OO/II/O

TRANSMISSION)

Request to Send Pulse (RTS) 5 10 µs
Clear to Send (CTS) 512 µs
Pin Output Configuration 8 ms
Handshake Time 12 µs
Data Set up Time 10 128 µs
Data Hold Time 128 256 µs
Synchronization Jitter 8 ms
CTS tonext RTS Pulse 98 ms

494-07.EPS - 494-03.TBL

7/22

M494

FUNCTIONAL DESCRIPTION (continued)
Display

The M494 is capable of directly driving a 1 digit
common anode LED displayat the max. sink cur­rent of 15mA per segment.The h+ipin is capable
of sinkinga max. currentof30mAso that thesetwo
segments can be drivenfrom the same pin and be
the samebrightness as the other segments.

On instructionfrom theinternal command decoder
the displayshows programmenumber,directionof
analogcontrolmovement,decadechangeor Mem­ory Addressingfunction active. Analog controls in
this context are defined as Tuning, Volume,Con­trast, Saturation & Brightness. The formats of the
displayforanalogcontroldirection,decadechange
and Memory Addressingare shown belowrespec­tively :

UP DOWN MEMORY

ADDRESSING

For the analog controls the above condition is
displayedwith an”overrun” time of 300ms.i.e.the
display will show the ”arrows” for a period of
300ms after the release of any analog control up
or down key. The Memory Addressing function
displayflashesat5HzaftertheMemoryAddressing
functionis commandedand continuesto flash until
a programmeis selectedor anyother command is
given. In1 * the g segmentonly flashesat 5Hzand
continues to flash until a programme number is
selected or any other command is given. If in
Memory Addressing and 1 * is pressed then the
display above is shown with segments g &d only
flashing at 5Hz until a programme number is se­lected or any other commands is given. When
Store orSet SkipFlag commandsareexecutedthe
whole display is flashedat 5Hz for 1second.

Keyboard

It is possibleto implement a keyboard with a max.
size of 35 keys as a 5 x 7 array.Fig. 8 shows the
arrangement ofthe key matrix. Each key connects
a row (a-g) with a column (D0-D4) with a max.
resistance of 10kΩ. De-bouncelogic is integrated
on the chip that only allows acceptance of a com­mand if the key is closed for longer than 40ms
except for the On/Standbyand On/Off commands
wheretherelevantkeysmust beclosedforapproxi­mately 100ms. Thisis equivalentto 2 receivedRC
commands).

|* I* AND

MEM.ADDR.

For the main keyboardmatrix (a-g x D0-D4), if the
logic detects two keys closed simultaneously the
display is blanked to indicate this condition to the
userand no commandis executed.When thelogic
detectsonly one key pressed the displaywill re-il­luminateand the command be executed.

Thisavoidsconfusionasto whichcommandshould
be executed and provides feed back to the user.
For the Option select line all options/commands
canbe active simultaneously.

1 * mode or decade mode can be selected on the
optionselect line by the presenceofa diode ornot
respectively.These two modes are only active for
the 20 programoptionand are describedbelow :

In 1 * mode the display will toggle in & out of the
conditionshown in the Display Section. Access to
programs in the first decade is made by simply
pressing any 0-9 program key and access to pro­grams inthe seconddecade, whateverthe current
program is made by pressing 1 * followed by any
0-9 program key.

494-08.EPS

In decade mode on pressingeither ±10 (decade)
keysthe displaywill light or extinguishthe halfdigit
respectively and simultaneously effect the tuning
information.e.g. ifthe deviceisin program 3press­ing+10 (decade)key willgiveprogram13andthen
pressing - 10 (decade) key will give program 3.
Pressing- 10 (decade)again will have no effect.

The 20 program option select acts like an enable
for the 1* or decademodes. i.e. the 1 * or decade
modes are only selectablein the 20 program op­tion. In 16 program option the function of the 1*
key,programkey 0, -10(decade) & + 10 (decade)
are changed to no function, programme 10, 11&
12 respectively. i.e. The differencebetween fig. 7
& 8 for those keys thatchange function.

If the 1 * key ispressed followedby brightness up
for examplethe device willincrease the brightness
only and reset the 1 * command i.e. the last

command from any command source will al­ways be executed if it is a single keystroke
commandand the 1 * command willbe reset by
it. Itis possibleto pressthe 1* keyon thekeyboard

andthen aprogram0-9commandfromRC orData
commandsourcesor vice versa.Thus there are2
methodsof selectinga program fromthe keyboard
for the 16 program option : directaccess (only up
to 12 programs) or Memory sequence up/down.
And there are 3 methods of selecting a program
from the keyboardfor the 20 programoption : 1 *
mode, decade mode and Memory sequence
up/down.

8/22

FUNCTIONAL DESCRIPTION (continued)

Figure7 : Keyboard16 Programs

M494

1

2

3

4

5

6

8

9

10

11

12

NORMALIZE CONTRASTUPSTORE

PROGRAM

ON/STANDBY
(TOGGLE)

VOLUME
UP

VOLUME
DOWN

SET SKIP
FLAG

SATURATIONUPMEMORY

CONTRAST
DOWN

BRIGHTNESSUPTUNE

BRIGHTNESS
DOWN

ON/OFF
(TOGGLE)

SEQUENCE
UP

STORE
ANALOG
VALUES

UP

TUNE
DOWN

BAND
SEQUENCE

MS
SEQUENCE

a

b

c

d

e

M494

7

MUTE
(TOGGLE)

SATURATION
DOWN

MEMORY
SEQUENCE
DOWN

MEMORY
ADDRESSING

f

16* AV1*

AV2

* = DEFAULT P/U =POWER UP

P/U*
OFF

P/U

STANDBY

g

OPTION
SELECT

SKIP OFF

h+i
D0
D1
D2
D3
D4

494-09.EPS

9/22

M494

FUNCTIONAL DESCRIPTION (continued)

Figure8 : Keyboard20 Programs

1

2

3

4

5

6

8

9

0

-10
DECADE

+10
DECADE

1*

NORMALIZE CONTRASTUPSTORE

PROGRAM

ON/STANDBY
(TOGGLE)

VOLUME
UP

VOLUME
DOWN

SET SKIP
FLAG

SATURATIONUPMEMORY

CONTRAST
DOWN

BRIGHTNESSUPTUNE

BRIGHTNESS
DOWN

ON/OFF
(TOGGLE)

SEQUENCE
UP

STORE
ANALOG
VALUES

UP

TUNE
DOWN

BAND
SEQUENCE

MS
SEQUENCE

a

b

c

d

e

M494

7

MUTE
(TOGGLE)

SATURATION
DOWN

MEMORY
SEQUENCE
DOWN

MEMORY
ADDRESSING

f

10/22

AV1*

20

* = DEFAULT P/U = POWER UP

AV2

P/U*
OFF

P/U

STANDBY

DECADE*
MODE

1*MODE

g

OPTION
SELECT

SKIP OFF

h+i
D0
D1
D2
D3
D4

494-10.EPS

M494

FUNCTIONAL DESCRIPTION (continued)
Data Input

Shown below are the codes for the commands :
see Table2.

The Data input will acceptsignals whosetiming is
defined in Figure 6 and electrical characteristics
defined in the table of static electrical charac­teristics. The EOT code must be transmittedafter
each command after amin. periodof 112ms.

Band Outputs

Four band outputsare providedfor selection ofthe
signalband:VHF I &III, UHF andCATV.Bandskip
logic is implemented so that by tieing the relevant
pin to V

a band can be skippedin regions of no

SS

transmission in that band. The bands can be se-

Table2 : DataCommands

Command

Number

0
1
2
3
4
5
6

7
8

9
10
11
12

13
14
15
16
17
18

19
20
21
22
23
24

25
26
27
28
29
30

The above table shown the differencebetween the 16 and 20program options with respect to the Data input commands.
Commands 10, 11, 12 & 13 change function between the two options. Commands 14, 15 & 16 should not be used in the 20 program option,
as they have no function.
NOP = No operation.

16 Programs 20 Programs D0 D1 D2 D3 D4

EOT
Program 1
Program 2
Program 3
Program 4
Program 5
Program 6

Program 7
Program 8
Program 9
Program 10
Program 11
Program 12

Program 13
Program 14
Program 15
Program 16
Normalise
Volumeup

Volumedown
Contrastup
Contrastdown
Brightness up
Brightness down
Saturation up

Saturation down
Memory Seq. up.
Memory Seq. down
On/standby (toggle)
Standby
Mute (toggle)

NO TRANSMISSION (pulled up) 1 1 1 1

Function Code

EOT
Program 1
Program 2
Program 3
Program 4
Program 5
Program 6

Program 7
Program 8
Program 9
Program 0
– 10 (decade)
+ 10(decade)

1*
NOP
NOP
NOP
Normalise
Volume up

Volume down
Contrast up
Contrast down
Brightness up
Brightness down
Saturation up

Saturation down
Memory Seq. up.
Memory Seq. down
On/standby (toggle)
Standby
Mute (toggle)

lected only in a rolling sequence by the band se­quence keyboard command. The sequence is as
follows : VHF III, UHF, VHF I, CATV.

Multi Standard Outputs

Twocoded multi standard outputs(or generalpur­pose TV system flags) are provided so that theTV
set can be designed for use in areasof more than
one transmission standard. This function requires
an externaldecodertorealise4differentstandards
e.g. PAL1, PAL2, NTSC, SECAM etc. The multi
standard sequence command available from the
keyboard gives a simple binary count at the two
outputs : 00, 01, 10, 11,00 etc. In Standbyand Off
statesthe multistandard outputs are pulled to logic
LO.

0
1
1
1
0
1
0

1
0
1
0
1
0

1
0
1
0
1
0

1
0
1
0
1
0

1
0
1
0
1
0

0
0
0
1
0
0
1

1
0
0
1
1
0

0
1
1
0
0
1

1
0
0
1
1
0

0
1
1
0
0
1

0
0
0
0
1
1
1

1
0
0
0
0
1

1
1
1
0
0
0

0
1
1
1
1
0

0
0
0
1
1
1

0
0
0
0
0
0
0

0
1
1
1
1
1

1
1
1
0
0
0

0
0
0
0
0
1

1
1
1
1
1
1

0
0
0
0
0
0
0

0
0
0
0
0
0

0
0
0
1
1
1

1
1
1
1
1
1

0
1
1
1
1
1

11/22

M494

FUNCTIONAL DESCRIPTION (continued)
AudioVisual Outputs

Twoaudio visualoutputsareprovidedfor automat­ic selection of a VCR and/or personal computer.
ThelogicstateofthepinsdependsontheAVoption
selected, the program option and the program
number selectedaccording to the truth tables be­low :

Table3 : AVOption 1 (16/20 Programs)

Program AV0 AV1

16/0

15/19

Others

Table4 : AVOption 2 (16/20 Programs)

Program AV0 AV1

8/8
7/7
6/6

Others

External pullup resistors must be used to realisea
logic HI asthe outputs are opendrain transistors.
See I/OConfiguration.

AFC Defeat Output

The AFCdefeat output is a TTL compatiblesignal
that is capableofswitchingthe AFC circuitry inand
out. The AFC defeat output is pulled LO on any
program change including memory sequence up
and downand is heldLO for 500msafterexecution
of thecommand.When tune up or downare com­mandedtheAFC defeatoutputistakento logicLO.
After the tuning operation the AFC defeat is held
LO for 1 second after the key is released (see
Figure 9). Onpower on& start up resets it is taken
to logic LO for approx. 1.1seconds.

Figure9

TUNE UP/DOWN:

KEYED

AFC DEFEAT
OUTPUT

RELEASED

Standby

The standby output is a push pull output capable
of directly drivingan NPN transistor for switching
a relay. The states of this pin are defined in the
definition of terms. When standbyis commanded,
availablefrom all commandsourcesas Standbyor
On/Standbycommands, the standby output is en­abled.

1
0
0

1
0
1
0

1s

0
1
0

0
1
1
0

If the device goes into Standby from On then any
program command will bring the device On with
that programselected.On/Offcommandfrom key­board only will execute the Off function.
On/Standby, Memory sequence up or down, 1 *
and ± 10(decade)commands from any command
source will bring the device On in the program
selected before Standbywith the displayshowing
that program only,i.e. the device executes an On
commandonly.

IfthedevicegoesintoStandbyfromPowereddown
thenthe On/Offcommand fromkeyboardonly and
any program command, On/Standby,Memory se­quence up or down, 1 * and ± 10 (decade)com­mands from any command source will bring the
device On in program 1. i.e. the device executes
an On command only.

Option Select

The Option select pin provides an extra line that
performs a ”hard wired keyboard function” in con­junction with the keyboard scanning lines D0-D4.
This line has integrated logic associated with it
that enables one or many of the functions to be
active simultaneously. In contrast, the keyboard
inputs a-g will allow one key active at any given
time. See keyboard section.

Various options can be selectedby theconnection
or not of a diode as shown in Figures7 & 8.
From left to right along the Option select line col­umn 1 selects the number of programs. A diode
connectedhere selects 20 programs (full comple­ment)and no diode (default) selects16 programs
onlythat canbe accessed.The 20 program option
only enables selection of 1 * or decade modes in
column 4. In column 2 the AV option defines the
stateof the AV outputs for twoprotocols.
Thesearedescribedin sectionAudiovisualoutput.
Column3definesthestate the M494powers up in.
If no connectionof a diode (default) is made here
the device powers up in the Off state. If a diode is

494-11.EPS

present then the device powersup in the Standby
state. In column 4, activated by the 20 program
option only, the presence of a diode places the
device in 1 * mode and the absence of a diode
selects decade mode. The diode and switch in
column 5 defeats the skip condition and enables
program memory words to be read with the skip
flagset.
This allows programming (or reprogramming) of
previouslyskipped words.

12/22

FUNCTIONAL DESCRIPTION (continued)
Skip Function

Program skip is implemented in the M494 by a
single memory bit associated with each program
word.The bit acts asa flagto thedeviceto indicate
that the programword should be skippedand the
next program word read from the memory in as­cending or descendingorder if the skip flag is set.
Programs are skipped only when accessed using
the memorysequenceup/downcommands.Direct
accesstoa programfrom thekeyboard,RC ordata
command sources will always override the skip
function. e.g. if skipis set on prog. 7 and prog.7 is
commanded from RC then prog. 7 will be tuned
even if there is nc prog. stored in that memory
location.

In order to program the skip bit and to defeat its
function when required two commands are avail­able : setskipflag andskip defeat.Theskip defeat
switch is designed to be activated by a faciapanel
on the TV set under which are infrequentlyused
controls.

On the set skipflag commandthe M494 stores the
currentcontentsof thetuning, band andMS count­ers and sets the skip bit. After the set skip flag
operation the contentsof thetuning,band and MS
counters will not change and the device continues
to output these values. The operationis transpar­ent to the user in termsof functionbut is indicated
on the display by the program number flashingat
5Hz for 1 second. In order to reset the skip bit for
any program word thedesired program shouldbe
selected with skip defeated. Astation shouldthen
be tuned,if required,andthen the store command
issued. The store command automatically resets
the skip flag.

The skipdefeatcommandenablesthe readingand
writing(plusresettingof skipflag)of memorywords
whoseskipflag is set.If skipisdefeatedthe device
will only access the number of programsselected
by the option select i.e. If 16 programs only are
selected then skip defeat will NOT enable access
to all20 programs.

Reset

There are twoconditionsunder which the M494 is
reset : power on and start up (On command).
Power on reset is triggered whenever V

DD

falls
below about 3V.
The duration of this reset is 110msafter V

DD

has

been restored.

M494

Power On Reset

(Powereddown to Offor Standbystates)
After the reset periodof 110ms:

a) The program counter is set to program1.
b) The outputs are disabled as defined in the Off

and Sta nd by sta tes. See Standby & Off
definitions.

c) The option selection, keyboard, momentary on

switchand,wheninstandby,thedisplay, RCand
data inputs become active. For the ”activity
level” ofthe keyboard inOff andstandbystates.
SeeStandby & Off definitions.

d) An internal register is set to indicate that the

devicehas powered up from the powereddown
state.

Start Up Reset

(Standbyor Off states to On state)
Astart upresetis instigated by thereceptionof the

commands given in the definition of terms or the
Standbysection.
The followingthen occurs :

a) The internal register indicating that the device

has powered up from the powered down state
isread :
I) If the register is set than the memory word

addressedby the program counter is loaded
into the tuning counter and then the analog
valuesare read rom thememory.

II) If the register is reset then the previously

selected tuning and analog values are left
unchanged.

b) The AFC is defeatedand the volumemuted for

a period of approx 1.7 secondsor 0.6seconds
longerthan the other analogoutputs.

c) The tuning and analogue outputs, except

volume,are enabledafter approx. 1.1 seconds.
d) The volumeoutput is enabled after 1.7 seconds
e) The standby output is pulled up internally to

logicHI
f) The internal register is reset.

If the device has either of the power up options
(power up in Off or standby states)selected then it
willperformapowerup resetbutall theoutputsand
commandsourceswillremaindisabled,thenonthe
On command,a start up reset will be performed.If
the device is required to power up in the On state
using the momentary mechanical switch con­nectedto the h+ipin thenit will performanordinary
power on resetfollowed immediatelyby a startup
reset. The outputs and command sources will be
enabledafter the periods defined above.

13/22

M494

FUNCTIONAL DESCRIPTION (continued)
Manual Tuning

Manual tuning commands tune up or down, are
available from keyboard only and are provided to
allow both manual station search and tuning
adjustments. If a continuous tuning up or down
commandismade from the keyboardthe speedof
movement of the tuning counter is as shown in
fig. 10 for the UHFand CATVbands. Timet

isthe

o

start time for the key being pressed. When the
FB/sync. coincidenceinput is a logic HI thetuning
speed is reduced to 16 steps/sec. If, at time t

the

o

FB/sync.coincidence input is at logic LO than the
tuning.sweep speed jumps immediately to 512
steps/sec.

For VHF III & I all these levels are shiftedup bya
factor of 2 & 4 respectivelygiving slowest speeds
of 8 steps/sec. and 16 steps/sec. and highest
speeds of 1024 steps/sec and 2048 steps/sec. If
the continuity of command is broken by releasing
the keyboard for example then the tuning speed
returns to its slowest speed when the FB/sync.
coincidenceinputis atlogic HI.Ifthe upperorlower
limitofa bandisreachedduring manualtuningthen
tuning will continuein the same directionfrom the

Figure10 : TuningSweep Speed (UHF & CATVBANDS)

opposite limit after a 480msdelay to allow for the
dischargeof the external network.

The tuning counter is 13 bits in length giving a
range of 8192 steps. The UHF band has a band­width of approx. 400MHz. Thus in the UHF band
the slowest speed of 4 steps/sec. gives a tuning
speed of about 200kHz/sec. The fastest speed of
512 step/sec. corresponds to a total band sweep
time of 16 seconds.

Program Memory Sequence

Acontinuousup/downprogrammemorycommand
from keyboardproduces a program change every
500ms. From remote control and data command
sourcesa continuousprogram memorysequence
command produces a program change approx.
every 500ms or every 5 received commands. A
memory sequence up or down command issued
fromanysourcewillbringthe deviceout ofstandby
to the program selected before standby was com­manded. The memory sequence up or down will
not thencommenceuntil the command isstopped
and reissued from any source (until an EOT has
been received or internally generated).

TUNING SWEEP
SPEED (STEP/SEC)

512

32

16

8
4

t0123

FB/SYNC.

COINCIDENCE

FB/SYNC.

COINCIDENCE

Time (sec)

FB/SYNC.

COINCIDENCE

494-12.EPS

14/22

FUNCTIONAL DESCRIPTION (continued)
Mute

The sound mute function is available as a toggle
command fromall commandsources.

There are other commands and functions during
which the soundis muted :

- FB/sync. coincidence - If there is no FB/sync.
coincidence under any conditions the sound is
muted.

- Startup reset- the soundismuted forapprox.1.7
seconds.

- Program change - the sound is muted for 0.6
seconds on any program change ; direct, 1 * +
0-9 program (only after the second keystroke),
±10 (decade)& Memory sequenceup/downcon­tinuousor single keystrokes.

- Standby& Off states - the soundis muted.

- Band sequence- sameas programchange.

The sound is demuted under the following condi­tions :

- When the mute command is received from any
source.

- WhenthedeviceiscommandedOn fromstandby
of Off, i.e. if the device was muted when the
standby command was issued then when On is
commandedit will always startupwith the sound

M494

demuted after the reset and settling period of
approx.17 seconds.

- Volume up - if volume up is commanded whilst
the soundis mutedthen the volumewill increase
from zero.

- Volume down - if volume down is commanded
whilstthe sound ismuted then there is no effect.

- Any program change - the sound is NOT de­muted.

MomentaryOn Switch

Provision is made for a momentary switch con­nectedbetweenthe h+i pinand groundto forcethe
M494 to makePower on and Start up resets auto­matically so that the device attains the On state
immediately.

Theconditionof theh+ipinislatchedafterthereset
period of 110ms. Therefore the period of switch
contactclosure shouldbe a min.of 120ms.

Figures.11& 12respectivelyshowin flowdiagram
form the two methodsfor storinga station : pretun­ing program selection and post tuning program
selection. Figures. 13, 14 & 15 show the select
programme subroutine for Figures. 11 & 12 for
either16programoption or20 programoption with
1*or±10 (decade modes).

15/22

M494

COMMANDS

Command Source Function

Programs 1-12 KB, D,RC

Programs 0-9 KB, D, RC

Programs 13-16 D, RC

– 10 (decade) KB, D, RC

+ 10(decade) KB, D, RC,

1* KB, D, RC

Vol. up/down
Bri. up/down
Sat. up/down
Con. up/down

Tune up/down KB Increments up or down the tuning counter. The speed or increment/decrement is

Mem. up/down KB, D, RC The program number (memory location) is incremented/decremented.
Mute (toggle) KB, D, RC Volume Mute. Seemute section.
Standby D, RC Commands the standby state.
On/standby

(toggle)
ON/OFF KB Commands the on state when in the off stateand commands the off state when in the

Store Program KB The currently addressed memory location is written from the tuning, band and MS

Store analog
Controls

Band Sequence KB Command the next band in the sequence as defined in bands outputs section. One

MS Sequence KB Increments the MS counter by binary one. One step for each key strobe.
Normalise

Analog
Memory

Addressing
Set SkipFlag KB Sets the skip flag on the currently selected program. Execution of this command is

Skip Defeat OS Defeats the functionof the skip bit to allow reading and writing of the currently selected

KB = Keyboard;D = Data; RC = RemoveControl; OS = OptionSelect.

(16 opt.)

(20 opt.)

(16 opt.)

(20 opt.)

(20 opt.)

(20 opt.)

KB, D, RC Increments up or down the relevant analog control counter every keystrobe or

KB, D, RC Commands the standby state from the on state and the on state from thestandby state.

KB The analog control memories are written in sequence from theanalog control counters.

KB, D, RC Reads the analog memories in sequence to their corresponding D/A’s. The analog

KB Strobes the program selected immediately after the memory addressing command

Reads the contents of the memory location : 2MSB’s to the MS counter, next 2 MSB’s
to the band counter next 12 MSB’s to the tuning counter andD/A and LSB to skip flag
register. Initiates an on command only after standby.

Reads the contents of the memory location : 2MSB’s to the MS counter, next 2 MSB’s
to the band counter next 12 MSB’s to the tuning counter andD/A and LSB to skip flag
register. Initiates an on command only after stndby.

Reads the contentsof the memory location : 2 MSB’s to the MS counter, next 2MSB’s
to the band counter next 12 MSB’s to the tuning counter andD/A and LSB to skip flag
register. Initiates a on command only after standby.

Sustracts 10 from the current program (if possible). Initiates an on command only after
standby.

Adds10to thecurrent program(if possible).Initiates an on command onlyafterstandby.

Commands the M494 to wait for a 0-9 program command or to reset on any other
command. Display shows half digit and g segment flashing at 5Hz. Initiates an on
command only after standby.

continuously every 112ms from KB and every102ms from the RC and data inputs. The
display shows an up/down arrow for 300ms min.

defined by Figure 10. The display shows anup/down arrow for 300ms min.

on state. See standby section.

counters and the skip flag is reset. See fig.11. Execution of this command is indicated
by the display flashing at 5Hz for 1 second.

Execution of this command is indicatedby the display flashing at 5Hz for 1 second.

step for each key strobe.

control outputs are disabled during the read sequence.

(post tuning program selection).See Figure 12.

indicated by the display flashing at 5Hz for 1 second.

program.

Figures 11 & 12 respectively showin flow diagram
from the two methods for storinga station : pretun­ing program selection and post tuning program
selection.

16/22

Figures 13, 14 & 15 show the select program
subroutine for Figures 11 & 12 for either 16 pro­gram option or20 programoption with 1* or ± 10
(decademodes).

COMMANDS (continued)

Figure11 : NormalMethods for Storing aStation (preselectionof program number)

BEGIN

SELECT

PROGRAM

M494

SET SKIP FLAG
AT CURRENT
PROGRAMME?

CONTINUE ?

No

No

Yes

TUNE

UP/DOWN

Yes

STORE

END

Yes

No

STATION
TUNED ?

SET SKIP

FLAG&
STORE

END

SELECTED PROGRAMME NO.
FLASHES AT 5Hz FOR 1 SECOND

494-19.EPS

17/22

M494

COMMANDS (continued)

Figure12 : SecondaryMethod for Storing a Station (postselectionof programnumber)

BEGIN

TIME

UP/DOWN

No

STORE
STATION AT
CURRENT
PROGRAMME ?

SET SKIP FLAG
AT CURRENT
PROGRAMME ?

CONTINUE ?

MEMORY

ADDRESSING

SELECT

PROGRAMME

(Direct Only)

END

STATION
TUNED ?

Yes

Yes

No

Yes

No

No

Yes

Figure13 : ProgramSelection Routine (16 program)

SET SKIP

FLAG &
STORE

THIS DISPLAY FLASHES
AT 5Hz UNTILA PROGRAMME
SELECTION IS COMPLETED
OR ANY OTHER COMMAND
IS GIVEN

SELECTED PROGRAMME
NO. FLASHES AT 5Hz
FOR 1 SECOND

STORE

END

494-20.EPS

18/22

KEY PRESENT
FOR DESIRED
PROGRAMME?

BEGIN

Yes

SELECT

NUMBER

END

No

MEMORY

SEQUENCE

END

UP OR DOWN TO
DESIRED
PROGRAMME

494-21.EPS

COMMANDS (continued)

Figure14 : ProgramSelection Routine (20 program,1 * mode)

BEGIN

M494

UPPER
DECADE ?

SELECT 1*

AGAIN

(TOGGLE)

PREVIOUS PROGRAMME
NUMBER IS DISPLAYED

SELECT

1*

No

SELECT

PROGRAM

END

No

Yes

SELECT

PROGRAM

CORRECT ?

Yes

g SEGMENT FLASHES
AT 5Hz UNTIL A
PROGRAM IS SELECTED
OR ANY OTHER
COMMAND IS GIVEN

Figure15 : ProgramSelectionRoutine (20 program, decade mode)

BEGIN

CHANGE
DECADE ?

No

Yes

END

494-22.EPS

SELECT + OR

- DECADE

SELECT

PROGRAM IF

NECESSARY

END

SELECT

PROGRAM

END

494-23.EPS

19/22

M494

INPUT/OUTPUTPINS
Figure16

Figure17

Figure18

Figure20

OSC. IN

FB/SYNC COINCIDENCE
OPTION SELECT

VOL, BRI, SAT, CON, TUNING
MEM. TIMING, AFCDEFEAT
MS, DISPLAY DRIVE

OSC. OUT

494-13.EPS

Figure19

494-15.EPS

Figure21

STANDBY OUTPUT

BAND

D0 - D4, a-g,h+i, AV
DATA HANDSHAKE

494-14.EPS

494-16.EPS

20/22

494-17.EPS

494-18.EPS

TYPICALAPPLICATION

Tuning

Voltage

C6

100nF

Ω

R16

82k

C5

100nF

Ω

R15

56k

C4

150nF

Ω

R14

33k

Ω

R13

33k

C2

100nF

High Voltage

R1

Z1

TAA550

Ω

R8

1%

1.6k

R9

5.6kΩ1%

T3

BC297

+5V

R5

6.8kΩ

(V) - 33V

H

V

R2

11mA

R2 = R1/4

R1 (kΩ)=

T4

BF259

Ω

R7

82k

C1

22µF

Ω

R6

4.7k

391920

R10

R11

M494

VHF I

VHF III

CATV

AV1

18

R33

UHF

2 x 5.6kΩ

R34

DL4DL3DL2DL1

AV0

17

R35

Ω

680

AFC DEF

OUT

R38R37

R36

Ω

5.6k

FB

+5V

Sync

MS1MS0

+12V

T9

BC177

R32

10kΩ

T8

BC177

R31

10kΩ

T7

BC177

R30

10kΩ

T5

BSX93

T6

CON

C10

28

BC177

R29

10kΩ

10µF

R25 8.2kΩ24R26 8.2kΩR27 8.2kΩ

R28 8.2kΩ

23

22

21

Ω

R12

3.3k

Ω

3.9k

1.5kΩ

VOL

SAT

LUM

C7

10µF

C8

10µF

C9

10µF

Ω

R17 22kΩ

R19 22kΩ

R21 22kΩ

R18 5.6kΩ

R20 5.6kΩ

R22 5.6k

27

34

33

R23 22kΩ

R24 5.6kΩ

31

+5V

500kHz

R39

4.7nF

Ω

2.2k

TDA8160

M708

R4

+5/12V

357

Ω

Ω

R3

1k

680

T2

BC177

16

Store Prog15Store Analog14TuneUp13TuneDown11BandSeq10PrgUp9PrgDown

D4

D3

D2

D1

D0

Relay

a

38

b

fh

abcdefghi

ce

d

i

M494

6

D5

D5

D5

D5

D5

85432

2 x 5.6kΩ

29 30

C12

100nF

Osc

25 4026 12 32 36 37

1

C11

100nF

21/22

494-24.EPS

M494

PACKAGE MECHANICAL DATA

40 PINS- PLASTICPACKAGE

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

a1 0.63 0.025

b 0.45 0.018
b1 0.23 0.31 0.009 0.012
b2 1.27 0.050

D 52.58 2.070
E 15.2 16.68 0.598 0.657

e 2.54 0.100
e3 48.26 1.900

F 14.1 0.555

i 4.445 0.175

L 3.3 0.130

Information furnished is believed to be accurateand reliable. However, SGS-THOMSON Microelectronics assumes no responsibility
for the consequences of use of such information nor for any infringement of patents or otherrights of third parties which may result
from its use. No licence is granted byimplication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics.
Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all
information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life
support devices or systems without express written approval of SGS-THOMSON Microelectronics.

 1995 SGS-THOMSON Microelectronics - All Rights Reserved

Purchase of I

2

I

C Patent. Rights to use these components in a I2C system, is granted provided that the system conformsto

Australia - Brazil - China- France- Germany - Hong Kong - Italy - Japan- Korea - Malaysia - Malta - Morocco

The Netherlands -Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom -U.S.A.

2

C Components of SGS-THOMSON Microelectronics, conveys a license under the Philips

2

the I

C Standard Specifications as defined by Philips.

SGS-THOMSON Microelectronics GROUP OF COMPANIES

PM-DIP40.EPS

22/22