Datasheet SC2268, SC2268-00 Datasheet (SILAN)

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REMOTE CONTROL ENCODER

DESCRIPTION

The SC2268 is a remote control encoder utilizing CMOS
Technology specially designed for use with the SC2128. Using a
special coding technique, SC2268 increases noise immunity to a
very great extent. It is housed in 16-Pins DIP Package and has a
maximum of eight input channels. Its high performance features
makes SC2268 a must in every fan and other electrical home
appliance remote control application.

FEATURES

* CMOS Technology
* Low power consumption
* Very high noise immunity
* Wide range of operating voltage: Vcc=2.2 ~ 5.0 Volts
* Transmits signals to a maximum of 8 channels
* Start wordcustom code options available

APPLICATIONS

* Fan remote control
* Air cleaner
* Humidifier
* Heater

PIN CONFIGURATION BLOCK DIAGRAM

15

I1

1

I2

2

I3

3

I4

4

SC2268

I5

5

I6

6

I7

7

I8

8

Vcc

16

OSCI

15

OSCO

14

Tx

13

OUT
C4

12

C5

11

C6

10

Vss

9

OSCI

OSCO

I1
I2
I3
I4
I5
I6
I7
I8

OSC

14

1
2
3

Key input

4

scanning

5
6
7
8

and

sampling

SC2268

ORDERING INFORMATION

SC2268
SC2268-00

Timing

circuit

Encoder

12 11 10
C4 C5 C6

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DIP-16

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Custom Cord C3=1
Custom Cord C3=0

Vcc Vss

16 9

Output
Waveform
Generator

13

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Tx OUT

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ABSOLUTE MAXIMUM RATINGS

Characteristic Symbol Value Unit

Supply Voltage V
Input/Output Voltage VIN/V
PowerDissipation P
Operating Temperature Topr -20 ~ +70
Storage Temperature Tstg -55 ~ +125

ELECTRICAL CHARACTERISTICS

Parameter Symbol Test conditions Min Typ Max Unit

Operating Voltage V
Operating Current(note) I

Standy-by Current I

Sinking Current of TxOUT I

Input Voltage of
I1 ~I8

Input Pull-Low Resistor R
Input Pull-High Resistor R
Oscillation frequency f
Note: For pins I1 ~ I8 : Any one of the said pins is set to HIGH while the others are set to LOW.

High Level V

Low level V

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CC

OUT

D

(Tamb=0 ~ 70°C,VCC-VSS=3 ± 10%V,Unless otherwise specified)

CC

OSC On, TxOUT is floating. -- 0.5 1 mA

OP

I1 ~ I8 = “L” OSC Stops.

SB

TxOUT is floating.
VOL=2.2V, VDD=3V 8 15 --

SINK

VOL=1.5V, VDD=3V 4 6 --

IH

IL

L

H

OSC

-- 2.2 3 5 V

-- 0.7V

-- 0 -- 0.3V

-- 30 50 80

-- 40 90 150

-- -- 455 -- kHz

0~6.0 V

Vss-0.2V ~ VCC+0.3V V

500 mW

0.5 1 3

CC

SC2268

°C
°C

µA

mA

-- V

CC

CC

V

kΩ
kΩ

PIN DESCRIPTION

Pin No. Symbol I/O Function

Key input pins.

1~8 I1 ~ I8 I

9 Vss -- Negative power supply.

11~12 C4~C5 I

10 C6 I

13 TxOUT O

15 OSCI I Oscillator Input Pin
14 OSCO O Oscillator Outpu Pin
16 Vcc -- Positive powersupply.

These pins are used to connect a maximum of 8 keys.
(each pin has a built-in pull-lowresistor).

Select input pin for start word.
These pins have internal pull-low resistor.
Select input pin for start word.
This pins have internal pull-high resistor.
Transmission output pin.
This pin is an open drain (NMOS) output and is used to transmit
signals. The carrier frequency is 38kHz.

These pins are used to externally
connect a 455kHz ceramic resonator.

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FUNCTIONAL DESCRIPTION

1. KEY INPUT

Up to eight keys can be directly connected to pins I1 ~

I8. Please refer to the diagram right.

Furthermore, SC2268 has a buit-in pull-low resistor of
about 60K ~ 110KΩ which reduces the need for
external components.

2. OSCILLATOR

An oscillation circuit can be constructed using the
CMOS inverter and Built-in Feedback resistor, 455kHz
crystal and two 220pf capacitors. The carrier frequency
is 38kHz.

Unless any of the 8 keys (I1~I8) is being operated,
the oscillat ion is automatically stopped. Thus, power
consumption is considerably reduced.

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Vcc

I1

1

I2

2

I3

3

I4

4

I5

5

I6

6

I7

7

I8

8

SC2268

OSCI

15 14

220pf 220pf

OSCO

455kHz

SC2268

SC2268

3. TRANMISSION WAVEFORM

When any of the 8 keys (I1 ~ I8) is set to “High”, the TxOUT outputs one start word followed by 2 identical
data words and a space. The code will be continuously outputted until the key is released. If for any
reason, the key was released during the code transmission process, the code that is being transmitted
during the key release action will still be completely outputted. Please refer to the following diagram.

I1 ~ I8

Tx OUT

Start

Data

Word

Word

20ms

1 Frame = 80ms

Data

Word

Space

80ms

Start

Word

Data

Data

Word

Word

*OSC = 455kHz

Space

Start

Word

Data

Word

Data
Word

Space

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4. TRANSMISSION CODE WAVEFORM

The transmission waveforms of the Start Word and the different Data Words generated when a specific input
key (I1~I8) is pressed are illustrated below (see also Transmission Code Pattern Sectioon):

CLK

start

W1

W2

W3

W4

W5

W6

W7

W8

1

0X

X=0.625ms

3X

X

SC2268

5. TRANSMISSION CODE PATTERN

The transmission code pattern of SC2268 is given in the table below.

Transmission

Startword 0011001 1

B0 B1 B2 B3 B4 B5 B6 B7

DataWord W1(I1) 0011101 0 0/p1
(Key pressed) W2 (I2) 0 1 0 1 1 0 0 0 0/p2

W3(I3) 0110001 0 0/p3
W4(I4) 1001110 0 0/p4
W5(I5) 1010011 0 0/p5
W6(I6) 1011000 1 0/p6
W7(I7) 1100010 1 0/p7
W8(I8) 1101001 0 0/p8

LSB MSB

C0 C1 C2 C3 C4 C5 C6 C7

Receiver

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6. START WORD CUSTOM CODE

The start word custom code has the following format:

LSB MSB

001C3 1C4 C5 C6

Note: C4 and C5 have internal pull-low resistors while C6 has an internal pull-high resistor.
The start word custom code table is given below :

C4 C5 C6 Custom Code (C0 to C7) Custom Code (C0 to C7)

0 0 0 00100001 00110001
0 0 1 00100011 00110011
0 1 0 00100101 00110101
0 1 1 00100111 00110111
1 0 0 00101001 00111001
1 0 1 00101011 00111011
1 1 0 00101101 00111101
1 1 1 00101111 00111111

OPERATION FLOW CHART

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Where: C3 = 1 (default value)

= bonding option available

C4 = “0” when floating or connected to Vss

= “1” when connected to Vcc

C5 = “0” when floating or connected to Vss

= “1” when connected to Vcc

C6 = “0” when connected to Vss

= “1” when floating or connected to Vcc

C3=0 C3=1(default)

Power on

SC2268

Stand by

No

No Yes

Key

press?

Yes

Enable oscillator

Debounce

Code

correct?

Yes

One frame

code transmit

Key

released?

No

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APPLICATION CIRCUIT

3V

battery

I1

Vcc

1

I2

2

I3

3

I4

4

I5

5

I6

6

I7

7

I8

8

OSCI

OSCO

Tx OUT

Vss

16
15
14

220pf

455kHz

220pf

13

C4

12

C5

11

C6

10

9

SC2268

Note: Please take note that C3(default value)=1. For more details, please refer to Start Word Custom Cord

Section.

* Place 47uf capacitor as near as possible to the SC2268 Vss pin.

47µf*

10 Ω

1kΩ

SC2268

IR LED

PACKAGE OUTLINE

DIP-16-300-2.54 UNIT:mm

2.54

0.25

6.40

19.4

3.51

0.46

1.50

7.62

15 degree

5.083.30

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Rev: 1.0 2000.12.31

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