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)
Page 1
*
*
*
*
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*
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
NC
A0
A1
A2
A3
A4
A5
A6
A7
Vss
NC
V
DD
Dout
OSC1
OSC2
TE
A11/D0
A10/D1
A9/D2
A8/D3
SM5028S
V1.0
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
A0
A1
A2
A3
A4
A5
A6
A7
Vss
V
DD
Dout
OSC1
OSC2
TE
A11/D0
A10/D1
A9/D2
A8/D3
SM5028RF
SM5028RF
2
12
RF ENCODER
S
AM
H
OP
Microelectronics Corp.
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
I
I
I
O
I
O
POWER
FUNCTION
Page 3
Address input , each pin can be
set to "0' , "1".
Address/data input.
Negative power supply.
Enables transmission.
Resistor connected between
these two pins determine the
system clock.
Serial output of encoded signals.
Positive power supply.
V1.0
SM5028RF
2
12
RF ENCODER
S
AM
H
OP
Microelectronics Corp.
Address/Data waveform
OSC
BIT "1"
BIT "0"
TE
Encoder
Dout
Page 4
FUNCTION DESCRIPTION
V1.0
Address
/Data Bit
< 1 word
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.
pilot period (12 bits)
1/3 bit sync. period
data code
period
address code period
Composition of information
An information word consists of 4 periods as illustrated below.
SM5028RF
2
12
RF ENCODER
S
AM
H
OP
Microelectronics Corp.
Page 5
2. OSC Frequency
SM5028RF's oscillator can be constructed by connecting a resistor between OSC1 and OSC2
pin.
V1.0
Encoder OSC Frequency
40
35
30
25
20
15
10
5
0
KHz
1 2 3 4
5
6
7
8
9 10
11 12 VOLTAGE
1.5M
1.2M
1.0M
820K
2.0M
3.0M
560K
The recommended oscillator frequency is F
OSCD
(SM5038RF decoder)= 8 - 10 F
OSCD
(SM5028RF
encoder)
~
SM5028RF
2
12
RF ENCODER
S
AM
H
OP
Microelectronics Corp.
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