三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5028RF
2
12
RF ENCODER
GENERAL DESCRIPTION
SM5028RF is a RF remote control
encoder paired with SM5038RF. It utilizes
CMOS technology. The chip has 12 bits
of
2-state address pins that provides 2
12
codes. SM5028RF/SM5038RF pair is
suitable for use on remote controller.
FEATURES
*
*
*
*
*
CMOS technology
Low power consumption
Wide range operating voltage, Vcc = 2.4~12V
Up to four data bits
High noise immunity
APPLICATION
*
*
*
*
*
*
Car Security
Garage Door
Ceiling Fan
Home Security/Automatic
Toys
Wireless doorbell
PIN ASSIGNMENTS (TOP VIEW)
A0
A1
A2
A3
A4
A5
A6
A7
Vss
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
SM5028RF
V
DD
Dout
OSC1
OSC2
TE
A11/D0
A10/D1
A9/D2
A8/D3
NC
A0
A1
A2
A3
A4
A5
A6
A7
Vss
1
2
3
4
5
6
7
8
9
10
SM5028S
20
19
18
17
16
15
14
13
12
11
NC
V
DD
Dout
OSC1
OSC2
TE
A11/D0
A10/D1
A9/D2
A8/D3
Page 1
V1.0
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5028RF
2
12
RF ENCODER
BLOCK DIAGRAM
OSC2
OSC1
TE
OSCILLATOR
÷
3 DIVIDER
DATA SELECT
& BUFFER
DOUT
A0
A1
A2
A3
A4
A5
A6
A7
÷
12 COUNTER &
1 OF 12 DECODER
SYNC.
CIRCUIT
12 TRANSMISSION
GATE CIRCUIT
BINARY DETECTOR
A11/D0 A10/D1 A9/D2 A8/D3
VDD
VSS
Page 2
V1.0
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5028RF
2
12
RF ENCODER
PIN DESCRIPTION
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
PIN NAME
A0
A1
A2
A3
A4
A5
A6
A7
V
SS
A8/D3
A9/D2
A10/D1
A11/D0
TE
OSC2
OSC1
Dout
V
DD
I/O
I
I
I
I
I
I
I
I
POWER
I
I
Address/data input.
I
I
I
O
I
O
POWER
Enables transmission.
Resistor connected between
these two pins determine the
system clock.
Serial output of encoded signals.
Positive power supply.
V1.0
Negative power supply.
Address input , each pin can be
set to "0' , "1".
FUNCTION
Page 3
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5028RF
2
12
RF ENCODER
FUNCTION DESCRIPTION
An information word consists of 4 periods as illustrated below.
1/3 bit sync. period
pilot period (12 bits)
address code period
data code
period
Composition of information
Address/Data waveform
OSC
BIT "1"
BIT "0"
Address
/Data Bit
TE
< 1 word
Encoder
Dout
4 words
Transmitted
Continuously
4 words
SM5028RF begin a 4-word transmission cycle upon receipt of a transmission enable
(TE active low). This cycle will repeat itself as long as the transmission enable (TE is
held low). Once the transmission enable returns high the encoder output completes
its final cycle and then stops as shown below.
Page 4
V1.0
三合微科股½有限公司
S
AM
H
OP
Microelectronics Corp.
SM5028RF
2
12
RF ENCODER
2. OSC Frequency
SM5028RF's oscillator can be constructed by connecting a resistor between OSC1 and OSC2
pin.
Encoder OSC Frequency
KHz
560K
40
35
30
820K
25
1.0M
20
1.2M
1.5M
15
2.0M
10
3.0M
5
0
1
2
3
4
5
6
7
8
9
10
11
12
VOLTAGE
~
The recommended oscillator frequency is F
OSCD
(SM5038RF decoder)= 8 - 10 F
OSCD
(SM5028RF
encoder)
Page 5
V1.0
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