ETC HT12E、HT12D、HT12F??

212 Series of Encoders
Features
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Operating voltage:
– 2.4V~5V for the HT12A/B/C
– 2.4V~12V for the HT12E/EA
Low power and high noise immunity CMOS
technology
Low standby current: 0.1µA (Typ.) at
VDD=5V
HT12A/B/C with a 38kHz carrier for infrared transmission medium
Minimum transmission word:
– Four words for the HT12E/EA
– One word for the HT12A/B/C
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Built-in oscillator needs only 5% resistor
Data code polarity:
– HT12A/C/E/EA: Positive polarity
– HT12B: Negative polarity
Minimal external components
18-pin DIP or 20-pin SOP package available
for HT12A/12B
14/18-pin DIP or 16/20-pin SOP or 16-pin
NSOP package available for HT12E
16/18-pin DIP or 16/20-pin SOP package
available for HT12C
Applications
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Burglar alarm system
Smoke and fire alarm system
Garage door controllers
Car door controllers
Car alarm system
Security system
Cordless telephones
Other remote control systems
General Description
The 212 encoders are a series of CMOS LSIs for
remote control system applications. They are
capable of encoding information which consists
of N address bits and 12–N data bits. Each
address/data input can be set to one of the two
logic states. The programmed addresses/data
are transmitted together with the header bits
via an RF or an infrared transmission medium
upon receipt of a trigger signal. The capability
to select a TE trigger on the HT12E/EA or a
DATA trigger on the HT12A/B/C further enhances the application flexibility of the 212 series of encoders. The HT12A/B/C additionally
provides a 38kHz carrier for infrared systems.
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212 Series of Encoders
Selection Table
Block Diagram
TE trigger
HT12E/EA
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212 Series of Encoders
DATA trigger
HT12A/B/C
Note: The address data pins are available in various combinations
(refer to the address/data table).
Pin Description
Pin Name
I/O
Internal
Connection
Description
CMOS IN
Pull-High
(HT12A/B/C)
A0~A7
I
NMOS
TRANSMISSION
GATE (HT12E) Input pins for address A0~A7 setting
They can be externally set to VDD or VSS.
NMOS
TRANSMISSION
GATE
PROTECTION
DIODE
(HT12EA)
NMOS
TRANSMISSION
GATE (HT12E)
AD8~AD11
I
Input pins for address/data AD8~AD11 setting
NMOS
TRANSMISSION They can be externally set to VDD or VSS (only for the
HT12E/EA).
GATE
PROTECTION
DIODE
(HT12EA)
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212 Series of Encoders
I/O
Internal
Connection
Description
D2~D11
I
CMOS IN
Pull-High
Input pins for data D2~D11 setting and transmission
enable, active low
They can be externally set to VSS or left open (see Note)
DOUT
O
CMOS OUT
L/MB
I
CMOS IN
Pull-High
Latch/Momentary transmission format selection pin:
Latch: Floating or VDD
Momentary: VSS
TE
I
CMOS IN
Pull-High
Transmission enable, active low (see Note)
OSC1
I
OSCILLATOR 1
Oscillator input pin
OSC2
O
OSCILLATOR 1
Oscillator output pin
X1
I
OSCILLATOR 2
455kHz resonator oscillator input
X2
O
OSCILLATOR 2
455kHz resonator oscillator output
VSS
I
—
Negative power supply (GND)
VDD
I
—
Positive power supply
Pin Name
Encoder data serial transmission output
Note: D2~D11 are all data input and transmission enable pins of the HT12A/B/C.
TE is a transmission enable pin of the HT12E/EA.
Approximate internal connection circuits
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212 Series of Encoders
Absolute Maximum Ratings*
Supply Voltage (HT12A/B/C) .......–0.3V to 5.5V
Supply Voltage (HT12E/EA) .........–0.3V to 13V
Input Voltage.................... VSS–0.3 to VDD+0.3V
Storage Temperature................. –50°C to 125°C
Operating Temperature............... –20°C to 75°C
*Note: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent
damage to the device. These are stress ratings only. Functional operation of this device at
these or any other conditions above those indicated in the operational sections of this
specification is not implied and exposure to absolute maximum rating conditions for extened
periods may affect device reliability.
Electrical Characteristics
(Ta=25°C)
HT12A/B/C
Symbol
Test Conditions
Parameter
Min.
Typ.
Max.
Unit
2.4
3
5
V
—
0.1
1
µA
—
0.1
1
µA
No load
FOSC=455kHz
—
200
400
µA
—
400
800
µA
VOH=0.9VDD (Source)
–1
–1.6
—
mA
VOL=0.1VDD (Sink)
2
3.2
—
mA
VDD
Conditions
—
—
VDD
Operating Voltage
ISTB
Standby Current
IDD
Operating Current
IDOUT
Output Drive Current
VIH
“H” Input Voltage
—
—
0.8VDD
—
VDD
V
VIL
“L” Input Voltage
—
—
0
—
0.2VDD
V
RDATA
D2~D11 Pull-High
Resistance
5V
—
150
300
kΩ
3V
Oscillator stops
5V
3V
5V
5V
VDATA=0V
(Ta=25°C)
HT12E/EA
Symbol
Test Conditions
Parameter
VDD
Operating Voltage
ISTB
Standby Current
IDD
Operating Current
Min.
Typ.
Max.
Unit
2.4
5
12
V
—
0.1
1
µA
12V
—
2
4
µA
3V
—
40
80
µA
—
150
300
µA
VDD
Conditions
—
—
3V
Oscillator stops
No load
12V FOSC=3kHz
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212 Series of Encoders
Symbol
Test Conditions
Parameter
VDD
5V
Min.
Typ.
Max.
Unit
VOH=0.9VDD (Source)
–1
–1.6
—
mA
VOL=0.1VDD (Sink)
1
1.6
—
mA
Conditions
IDOUT
Output Drive Current
VIH
“H” Input Voltage
—
—
0.8VDD
—
VDD
V
VIL
“L” Input Voltage
—
—
0
—
0.2VDD
V
FOSC
Oscillator Frequency
5V
ROSC=1.1MΩ
—
3
—
kHz
RTE
TE Pull-High Resistance
5V
VTE=0V
—
1.5
3
MΩ
Functional Description
Operation
The 212 series of encoders begin a 4-word transmission cycle upon receipt of a transmission enable
(TE for the HT12E/EA or D2~D11 for the HT12A/B/C, active low). This cycle will repeat itself as long
as the transmission enable (TE or D2~D11) is held low. Once the transmission enable returns high
the encoder output completes its final cycle and then stops as shown below.
Transmission timing for the HT12E/EA
Transmission timing for the HT12A/B/C (L/MB=Floating or VDD)
Transmission timing for the HT12A/B/C (L/MB=VSS)
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212 Series of Encoders
Information word
Transmission of L/MB is the Latch/Momentary type selection pin. If L/MB=1 the device is in the latch
mode (for use with the latch type of data decoders). When the transmission enable is removed during
a transmission, the DOUT pin outputs a complete word and then stops. On the other hand, if L/MB=0
the device is in the momentary mode (for use with the momentary type of data decoders). When the
transmission enable is removed during a transmission, the DOUT outputs a complete word and then
adds 7 words all with the “1” data code.
An information word consists of 4 periods as illustrated below.
Composition of information
Address/data waveform
Each programmable address/data pin can be externally set to one of the following two logic states as
shown below.
Address/Data bit waveform for the HT12E/EA
Address/Data bit waveform for the HT12A/C
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212 Series of Encoders
The HT12B data code polarity is inverted:
Address/Data bit waveform for the HT12B
The address/data bits of the HT12A/B/C are transmitted with a 38kHz carrier for infrared remote
controller flexibility.
Address/data programming (preset)
The status of each address/data pin can be individually pre-set to logic “high” or “low”. If a
transmission-enable signal is applied, the encoder scans and transmits the status of the 12 bits of
address/data serially in the order A0 to AD11 for the HT12E/EA encoder and A0 to D11 for the
HT12A/B/C encoder.
During information transmission these bits are transmitted with a preceding synchronization bit.
But if the trigger signal is not applied, the chip enters the standby mode and consumes a reduced
current which is less than 1µA for a supply voltage of 5V.
Usual applications preset the address pins with individual security codes by the DIP switches or PCB
wiring, while the data is selected by the push button or electronic switches.
The following figure shows an application using the HT12E/EA:
The transmitted information is as shown:
Pilot
&
Sync.
A0
A1
A2
A3
A4
A5
A6
A7
AD8
AD9
1
0
1
0
0
0
1
1
1
1
8
AD10 AD11
1
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212 Series of Encoders
Address/Data sequence
The following provides a table of the address/data sequence for various models of the 212 series of
encoders. A correct device should be selected according to the requirements of individual address and
data.
Address/Data Bits
Part No.
0
1
2
3
4
5
6
7
8
9
10
11
HT12A
A0
A1
A2
A3
A4
A5
A6
A7
D8
D9
D10
D11
HT12B
A0
A1
A2
A3
A4
A5
A6
A7
D8
D9
D10
D11
HT12C
A0
A1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
HT12E/EA
A0
A1
A2
A3
A4
A5
A6
A7
AD8
AD9 AD10 AD11
Transmission enable
For the HT12E/EA encoders, transmission is enabled by applying a low signal to the TE pin. But for
the HT12A/B/C encoders, transmission is enabled by applying a low signal to one of the data pins
D2~D11.
Two erroneous application circuits of HT12EA
HT12EA is equipped with a protection diode in its input pins, that is the difference of HT12EA from
HT12E (see the “Approximate internal connection circuits” on page 6). The HT12EA must exactly
practice the application circuit by HOLTEK’s supply (see the “Application circuits”).
• The cause for the error: AD8~AD11 pins input voltage > VDD+0.3V
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212 Series of Encoders
• The cause for the error: The IC’s power source from AD8~AD11 pins
Flowchart
• HT12A/B/C
HT12E/EA
Note: D2~D11 are transmission enables of the HT12A/B/C.
TE is the transmission enable of the HT12E/EA.
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212 Series of Encoders
Oscillator frequency vs supply voltage
The recommended oscillator frequency is FOSCD (decoder) ≅ 50 FOSCE (HT12E/EA encoder)
1
≅ FOSCE (HT12A/B/C encoder).
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212 Series of Encoders
Package Information
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212 Series of Encoders
Application Circuits
Note: Typical infrared diode: EL-1L2 (KODENSHI CORP.)
Typical RF transmitter: JR-220 (JUWA CORP.)
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