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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 stand-by current Minimum transmission word: - Four words for the HT12E/EA
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- One word for the HT12A/B/C A built-in oscillator with only a 5% resistor HT12A/B/C with a 38KHz carrier for InfraRed transmission medium Data code polarity: - HT12A/C/E/EA: Positive polarity - HT12B: Negative polarity Minimal external components
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Applications
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Burglar alarm system Smoke and fire alarm system Garage door controllers Car door controllers
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Car alarm system Security system Cordless telephones Other remote control systems
General Description
The 2 12 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 Infra-Red 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 2 12 series of encoders. The HT12A/B/C additionally provides a 38KHz carrier for Infra-Red systems.
Selection Table
Function Address Address/ Data Oscillator Trigger Item No. Data No. No. HT12A HT12B HT12C 2 HT12E/EA 8 8 8 0 0 4 10 0 0 4 4 455K Hz resonator 455K Hz resonator 455K Hz resonator RC oscillator D8~D11 D8~D11 D2~D11 Package 18 DIP 20 SOP 18 DIP 20 SOP 16 DIP 16 SOP 18 DIP Carrier Negative Output Polarity 38K Hz 38K Hz No Yes
38K Hz
No
0
TE
14/18 DIP 16/20 SOP 16 NSOP
No
No
Note: Address/Data represents pins that can be address or data according the decoder requirement.
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212 Series of Encoders
Block Diagram
TE trigger
HT12E/EA
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DATA trigger
HT12A/B/C
Note: The address data pins are available in various combinations (refer to the address/data table).
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Pin Description
Pin Name I/O Internal Connection
CMOS IN Pull-High (HT12A/B/C) 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) CMOS IN Pull-High CMOS OUT CMOS IN Pull-High CMOS IN Pull-High OSCILLATOR 1 OSCILLATOR 1 OSCILLATOR 2 OSCILLATOR 2 -- -- Input pins for data D2~D11 setting and transmission enable, active low They can be externally set to VSS or left open (see Note). Encoder data serial transmission output Latch/Momentary transmission format selection pin: Latch: Floating or VDD Momentary: VSS Transmission enable, active low (see Note). Oscillator input pin Oscillator output pin 455KHz resonator oscillator input 455KHz resonator oscillator output Negative power supply (GND) Positive power supply
Description
A0~A7
I
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D2~D11 DOUT L/MB
I O I
TE OSC1 OSC2 X1 X2 VSS VDD
I I O I O I I
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.
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Approximate internal connection circuits
NMOS TRANSMISSION GATE CMOS IN Pull-High CMOS OUT OSCILLATOR 1
EN OSC1
OSC2
OSCILLATOR 2
NMOS TRANSMISSION GATE PROTECTION DIODE
X1
X2 VDD
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Absolute Maximum Ratings
Supply Voltage (HT12A/B/C) ....... -0.3V to 5.5V Input Voltage.................... VSS-0.3 to VDD+0.3V Operating Temperature............... -20C to 75C Supply Voltage (HT12E/EA) ......... -0.3V to 13V Storage Temperature................. -50C to 125C
Electrical Characteristics
HT12A/B/C
(Ta=25C)
Symbol
VDD ISTB
Parameter VDD
Operating Voltage Stand-by Current -- 3V 5V Operating Current 3V 5V Output Drive Current "H" Input Voltage "L" Input Voltage D2~D11 Pull-High Resistance 5V -- -- 5V
Test Condition Condition
-- Oscillator stops. No load FOSC=455KHz VOH=0.9VDD (Source) VOL=0.1VDD (Sink) -- -- VDATA=0V
Min.
2.4 -- -- -- -- -1 2 0.8VDD 0 --
Typ.
3 0.1 0.1 200 400 -1.6 3.2 -- -- 150
Max.
5 1 1 400 800 -- -- VDD 0.2VDD 300
Unit
V
A A A A
IDD
IDOUT VIH VIL RDATA
mA mA V V K
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212 Series of Encoders
HT12E
(Ta=25C)
Symbol
VDD ISTB
Parameter VDD
Operating Voltage Stand-by Current -- 3V 12V Operating Current
Test Condition Condition
-- Oscillator stops.
Min.
2.4 -- -- -- -- -1 1 0.8VDD 0 -- --
Typ.
5 0.1 2 40 150 -1.6 1.6 -- -- 3 1.5
Max.
12 1 4 80 300 -- -- VDD 0.2VDD -- 3
Unit
V
A A A A
IDD
No load 12V FOSC=3KHz 5V -- -- 5V 5V VOH=0.9VDD (Source) VOL=0.1VDD (Sink)
3V
IDOUT VIH
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Output Drive Current "H" Input Voltage "L" Input Voltage Oscillator Frequency TE Pull-High Resistance
mA mA V V KHz M
-- -- ROSC=1.1M VTE=0V
VIL FOSC RTE
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Functional Description
Operation
The 212 series of encoders begins 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 in Fig.1 for the HT12E/EA and in Fig.2,3 for the HT12A/B/C.
TE < 1 word Encoder DOUT 4 words Transmitted Continuously 4 words
Fig.1 Transmission timing for the HT12E/EA
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Fig.2 Transmission timing for the HT12A/B/C (L/MB=Floating or VDD)
Fig.3 Transmission timing for the HT12A/B/C (L/MB=VSS)
Information word
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 3 periods as illustrated in Fig.4.
Fig.4 Composition of information
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Address/data waveform
Each programmable address/data pin can be externally set to one of the following two logic states as shown in Fig.5 (for the HT12E/EA) and Fig.6,7 (for the HT12A/B/C):
Fig.5 Address/Data bit waveform for the HT12E/EA
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Fig.6 Address/Data bit waveform for the HT12A/C The HT12B data code polarity is inverted:
Fig.7 Address/Data bit waveform for the HT12B The address/data bits of the HT12A/B/C are transmitted with a 38KHz carrier for Infra-Red remote controller flexibility.
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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 stand-by mode and consumes a reduced current which is less than 1A 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:
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The transmitted information is as shown:
Pilot & Sync.
A0 1
A1 0
A2 1
A3 0
A4 0
A5 0
A6 1
A7 1
AD8 1
AD9 1
AD10 AD11 1 0
Address/Data sequence
The following provides a table of the address/data sequence for various models of the 212 series encoders. A correct device should be selected according to the requirements of individual address and data.
HOLTEK Part No.
HT12A HT12B HT12C HT12E/EA
Address/Data Bits
0 A0 A0 A0 A0 1 A1 A1 A1 A1 2 A2 A2 D2 A2 3 A3 A3 D3 A3 4 A4 A4 D4 A4 5 A5 A5 D5 A5 6 A6 A6 D6 A6 7 A7 A7 D7 A7 8 D8 D8 D8 AD8 9 D9 D9 D9 10 D10 D10 D10 11 D11 D11 D11
AD9 AD10 AD11
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212 Series of Encoders
Transmission enable
For the HT12E/EA encoder, transmission is enabled by applying a low signal to the TE pin. But for the HT12A/B/C encoders transmission it is enabled by applying a low signal to one of the data pins D2~D11.
Two mistakable application circuits of HT12EA
HT12EA equip a protection diode in input pins, that is the difference of HT12EA from HT12E (see the "Approximate internal connection circuits" on page4). The HT12EA must exact practice the application circuit by HOTEK's supply (see the "Application circuit" on page 14 or page8). Two mistakable examples as below.
OSC2
VDD
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OSC1 TE VSS AD11 AD10 AD9 AD8 12V
HT12EA
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mistakable cause: AD8~AD11 pins input voltage > VDD+0.3V
12V OSC2 VDD
OSC1 TE VSS
AD11 AD10 AD9 AD8
HT12EA
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mistakable cause: The IC's power source from AD8~AD11 pins
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Flowchart
HT12A/B/C
HT12E/EA
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Note: D2~D11 are transmission enables of the HT12A/B/C. TE is the transmission enable of the HT12E/EA.
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Oscillator frequency chart of the HT12E/EA
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The recommended oscillator frequency is FOSCD (decoder) 50 FOSCE (HT12E/EA) 1 FOSCE (HT12A/B/C). 3
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Package Information
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8 Address 8 Address 2 Address/Data
A0 A0 A1 A2 A3 A4 A5 A6 1 2 3 4 5 6 7 14 13 12 11 10 9 8 VDD DOUT OSC1 OSC2 TE VSS A7 A1 A2 A3 A4 A5 A6 A7 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VDD DOUT OSC1 OSC2 TE AD11 AD10 VSS
8 Address 4 Address/Data
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 VDD DOUT OSC1 OSC2 TE AD11 AD10 AD9 AD8
HT12E/EA - 14 DIP
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HT12E/EA - 16 SOP
HT12E/EA - 18 DIP
8 Address 4 Address/Data
NC A0 A1 A2 A3 A4 A5 A6 A7 VSS 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 NC VDD DOUT OSC1 OSC2 TE AD11 AD10 AD9 AD8
HT12E/EA - 20 SOP
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Application Circuits
Application circuit 1 Application circuit 2
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Application circuit 3
Application circuit 4
Transmitter Circuit VDD 1 2 3 4 5 6 7 8 9 A0 A1 A2 A3 A4 A5 A6 A7 VSS VDD DOUT OSC1 OSC2 TE AD11 AD10 AD9 AD8 18 17 16 15 ROSC 14 13 12 11 10
HT12E/EA
Note: Typical infrared diode: EL-1L2 (KODENSHI CORP.) Typical RF transmitter: JR-220 (JUWA CORP.) FD-493TX (FISCHER-OLSEN, GERMANY).
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