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2
Features
* * * *
12
HT12A/HT12E Series of Encoders
Minimum transmission word - Four words for the HT12E - One word for the HT12A Built-in oscillator needs only 5% resistor Data code has positive polarity Minimal external components HT12A/E: 18-pin DIP/20-pin SOP package
Operating voltage - 2.4V~5V for the HT12A - 2.4V~12V for the HT12E Low power and high noise immunity CMOS technology Low standby current: 0.1mA (typ.) at VDD=5V HT12A with a 38kHz carrier for infrared transmission medium
* * * * *
Applications
* * * *
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 or a DATA trigger on the HT12A further enhances the application flexibility of the 212 series of encoders. The HT12A additionally provides a 38kHz carrier for infrared systems.
Selection Table
Function Address Address/ Data Oscillator No. Data No. No. Part No. HT12A HT12E 8 8 0 4 4 0 455kHz resonator RC oscillator Trigger D8~D11 TE Package 18 DIP 20 SOP 18 DIP 20 SOP Carrier Output 38kHz No Negative Polarity No No
Note: Address/Data represents pins that can be address or data according to the decoder requirement.
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April 11, 2000
HT12A/HT12E
Block Diagram
TE trigger HT12E
OSC2 OSC1
TE
O s c illa to r
3 D iv id e r
D a ta S e le c t & B u ffe r S ync. C ir c u it
DOUT
A0 1 2 T r a n s m is s io n G a te C ir c u it A7
1 2 C o u n te r & 1 of12 D ecoder
B in a r y D e te c to r
AD8
AD 11
VDD
VSS
DATA trigger HT12A
X2 X1
O s c illa to r L /M B A0 1 2 T r a n s m is s io n G a te C ir c u it A7
5 7 6 D iv id e r
D a ta S e le c t & B u ffe r S ync. C ir c u it
DOUT
1 2 C o u n te r & 1 of12 D ecoder
B in a r y D e te c to r
D8
D11
VDD
VSS
Note: The address data pins are available in various combinations (refer to the address/data table).
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April 11, 2000
HT12A/HT12E
Pin Assignment
8 -A d d re s s 4 -D a ta
A0 A1 A2 A3 A4 A5 A6 A7 VSS 9 8 7 6 5 4 3 2 1 18 17 16 15 14 13 12 11 10 VDD DOUT X1 X2 L /M B D11 D10 D9 D8
8 -A d d re s s 4 -D a ta
NC 1 2 3 4 5 6 7 8 9 10 A0 A1 A2 A3 A4 A5 A6 A7 VSS 20 19 18 17 16 15 14 13 12 11 NC VDD DOUT X1 X2 L /M B D11 D10 D9 D8
8 -A d d re s s 4 -A d d r e s s /D a ta
8 -A d d re s s 4 -A d d r e s s /D a ta
NC 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
A0 A1 A2 A3 A4 A5 A6 A7 VSS 9 8 7 6 5 4 3 2
1
18 17 16 15 14 13 12 11 10
VDD DOUT OSC1 OSC2 TE AD11 AD10 AD9 AD8
A0 A1 A2 A3 A4 A5 A6 A7 VSS
H T12A 1 8 D IP
H T12A 20 SO P
HT12E 1 8 D IP
HT12E 20 SO P
Pin Description
Pin Name I/O Internal Connection CMOS IN Pull-high (HT12A) A0~A7 I NMOS Input pins for address A0~A7 setting TRANSMISSION These pins can be externally set to VSS or left open GATE PROTECTION DIODE (HT12E) NMOS TRANSMISSION Input pins for address/data AD8~AD11 setting GATE PROTECTION These pins can be externally set to VSS or left open DIODE (HT12E) CMOS IN Pull-high CMOS OUT CMOS IN Pull-high Input pins for data D8~D11 setting and transmission enable, active low These pins should 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 Description
AD8~AD11
I
D8~D11 DOUT L/MB
I O I
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April 11, 2000
HT12A/HT12E
Pin Name TE OSC1 OSC2 X1 X2 VSS VDD I/O I I O I O I I Internal Connection CMOS IN Pull-high OSCILLATOR 1 OSCILLATOR 1 OSCILLATOR 2 OSCILLATOR 2 3/4 3/4 Description Transmission enable, active low (see Note) Oscillator input pin Oscillator output pin 455kHz resonator oscillator input 455kHz resonator oscillator output Negative power supply, grounds Positive power supply
Note: D8~D11 are all data input and transmission enable pins of the HT12A. TE is a transmission enable pin of the HT12E. Approximate internal connections
NMOS T R A N S M IS S IO N GATE C M O S IN P u ll- h ig h CMOS OUT
EN OSC1
O S C IL L A T O R 1
OSC2
O S C IL L A T O R
2
N M O S T R A N S M IS S IO N G A T E P R O T E C T IO N D IO D E
X2 V
DD
X1
Absolute Maximum Ratings
Supply Voltage (HT12A) ..............-0.3V to 5.5V Input Voltage....................VSS-0.3 to VDD+0.3V Operating Temperature...............-20C to 75C Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maximum Ratings may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Supply Voltage (HT12E) ...............-0.3V to 13V Storage Temperature.................-50C to 125C
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HT12A/HT12E
Electrical Characteristics
HT12A Symbol VDD ISTB IDD IDOUT VIH VIL RDATA HT12E Symbol VDD ISTB IDD IDOUT VIH VIL fOSC RTE Parameter Operating Voltage Standby Current Operating Current Output Drive Current H Input Voltage L Input Voltage Oscillator Frequency TE Pull-high Resistance Test Conditions VDD 3/4 3V 12V 3V Conditions 3/4 Oscillator stops Min. 2.4 3/4 3/4 3/4 3/4 -1 1 0.8VDD 0 3/4 3/4 Typ. 5 0.1 2 40 150 -1.6 1.6 3/4 3/4 3 1.5 Max. 12 1 4 80 300 3/4 3/4 VDD 0.2VDD 3/4 3 Parameter Operating Voltage Standby Current Operating Current Output Drive Current H Input Voltage L Input Voltage D8~D11 Pull-high Resistance Test Conditions VDD 3/4 3V 5V 3V 5V 5V 3/4 3/4 5V Conditions 3/4 Oscillator stops No load fOSC=455kHz VOH=0.9VDD (Source) VOL=0.1VDD (Sink) 3/4 3/4 VDATA=0V Min. 2.4 3/4 3/4 3/4 3/4 -1 2 0.8VDD 0 3/4 Typ. 3 0.1 0.1 200 400 -1.6 3.2 3/4 3/4 150 Max. 5 1 1 400 800 3/4 3/4 VDD 0.2VDD 300 Ta=25C Unit V mA mA mA mA mA mA V V kW Ta=25C Unit V mA mA mA mA mA mA V V kHz MW
No load 12V fOSC=3kHz 5V 3/4 3/4 5V 5V VTE=0V VOH=0.9VDD (Source) VOL=0.1VDD (Sink) 3/4 3/4 ROSC=1.1MW
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HT12A/HT12E
Functional Description
Operation The 212 series of encoders begin a 4-word transmission cycle upon receipt of a transmission enable (TE for the HT12E or D8~D11 for the HT12A, active low). This cycle will repeat itself as long as the transmission enable (TE or D8~D11) is held low. Once the transmission enable returns high the encoder output completes its final cycle and then stops as shown below.
TE < 1 w o rd E ncoder DOUT 4 w o rd s T r a n s m itte d C o n tin u o u s ly
4 w o rd s
Transmission timing for the HT12E
D8~D 11 K e y - in < 1 w o rd E ncoder DOUT 1 w o rd T r a n s m itte d C o n tin u o u s ly w ith 3 8 k H z c a r r ie r 1 w o rd
Transmission timing for the HT12A (L/MB=Floating or VDD)
D8~D11 K e y - in < 1 w o rd E ncoder DOUT 7 w o rd s 1 w o rd ( a ll d a ta = 1 ) T r a n s m itte d C o n tin u o u s ly 1 w o rd
( a ll d a ta = 1 ) 7 w o rd s
Transmission timing for the HT12A (L/MB=VSS)
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HT12A/HT12E
Information word 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.
1 /3 b it s y n c . p e r io d p ilo t p e r io d ( 1 2 b its ) a d d r e s s c o d e p e r io d d a ta c o d e p e r io d
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.
fO
SC
"O n e " "Z e ro " A d d re s s / D a ta B it
Address/Data bit waveform for the HT12E
fO
SC
"O n e " D a ta B it "Z e ro " D a ta B it "O n e " A d d r e s s B it "Z e ro " A d d r e s s B it
38kH z c a r r ie r
Address/Data bit waveform for the HT12A
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April 11, 2000
HT12A/HT12E
The address/data bits of the HT12A 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 encoder and A0 to D11 for the HT12A encoder. During information transmission these bits are transmitted with a preceding synchronization bit. If the trigger signal is not applied, the chip enters the standby mode and consumes a reduced current of less than 1mA for a supply voltage of 5V. Usual applications preset the address pins with individual security codes using DIP switches or PCB wiring, while the data is selected by push buttons or electronic switches. The following figure shows an application using the HT12E:
OSC1
OSC2 DOUT
T r a n s m is s io n m e d iu m
VDD
A0
A1
A2
A3
A4
A5
A6
A7
VSS
TE
AD8
AD 9 AD 10 AD 11
V
DD
VSS
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
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April 11, 2000
HT12A/HT12E
Address/Data sequence The following provides the address/data sequence table for various models of the 212 series of encoders. The correct device should be selected according to the individual address and data requirements. Part No. HT12A HT12E Address/Data Bits 0 A0 A0 1 A1 A1 2 A2 A2 3 A3 A3 4 A4 A4 5 A5 A5 6 A6 A6 7 A7 A7 8 D8 AD8 9 D9 10 D10 11 D11
AD9 AD10 AD11
Transmission enable For the HT12E encoders, transmission is enabled by applying a low signal to the TE pin. For the HT12A encoders, transmission is enabled by applying a low signal to one of the data pins D8~D11. Two erroneous HT12E application circuits The HT12E must follow closely the application circuits provided by Holtek (see the Application circuits).
* Error: AD8~AD11 pins input voltage > VDD+0.3V
OSC2 VDD
OSC1 TE VSS
AD11 AD10 AD9 AD8 12V
HT12E
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April 11, 2000
HT12A/HT12E
* Error: The ICs power source is activated by pins AD8~AD11
12V OSC2 VDD
OSC1 TE VSS
AD 11 AD 10 AD9 AD8
HT12E
Flowchart
* HT12A
Pow eron
* HT12E
Pow eron
S ta n d b y m o d e
S ta n d b y m o d e
No
D a ta e n a b le ? Yes D a ta w ith c a r r ie r s e r ia l o u tp u t
No
T r a n s m is s io n e n a b le d ? Yes 4 d a ta w o rd s tr a n s m itte d
D a ta s till e n a b le d ? No L /M B = G N D ? No S e n d th e la s t c o d e
Yes
No
T r a n s m is s io n s till e n a b le d Yes
Yes
4 d a ta w o rd s tr a n s m itte d c o n tin u o u s ly
S e n d 1 7 tim e s fo r a ll o f th e d a ta c o d e s
Note: D8~D11 are transmission enables of the HT12A. TE is the transmission enable of the HT12E.
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April 11, 2000
HT12A/HT12E
Oscillator frequency vs supply voltage
fO S C (S c a le ) R 7 .0 0 470k 510k 6 .0 0 560k 620k 5 .0 0 680k 750k 4 .0 0 820k 910k 1 .0 M (3 k H z )3 .0 0 1 .2 M 1 .5 M 2 .0 0 2 .0 M 1 .0 0
OSC
(W )
2
3
4
5
6
7
8
9
10
11
12
13 V
DD
(V D C )
The recommended oscillator frequency is fOSCD (decoder) @ 50 fOSCE (HT12E encoder) 1 @ fOSCE (HT12A encoder) 3
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April 11, 2000
HT12A/HT12E
Application Circuits
V
DD
100W
T r a n s m itte r C ir c u it V
DD
1 2 3 4 5 6 7 8 9
A0 A1 A2 A3 A4 A5 A6 A7 VSS
VDD DOUT X1 X2 L /M B D11 D10 D9 D8
18 17 16 15 14 13 12 11 10 10kW 455kW 10M W
8050 2 100pF 3 4 5 6 7 8 9 100pF
1
A0 A1 A2 A3 A4 A5 A6 A7 VSS
VDD DOUT OSC1 OSC2 TE AD11 AD10 AD9 AD8
18 17 16 15 14 13 12 11 10 R
OSC
HT12A
Note: Typical infrared diode: EL-1L2 (KODENSHI CORP.) Typical RF transmitter: JR-220 (JUWA CORP.)
HT12E
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April 11, 2000
HT12A/HT12E
Holtek Semiconductor Inc. (Headquarters) No.3 Creation Rd. II, Science-based Industrial Park, Hsinchu, Taiwan, R.O.C. Tel: 886-3-563-1999 Fax: 886-3-563-1189 Holtek Semiconductor Inc. (Taipei Office) 5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C. Tel: 886-2-2782-9635 Fax: 886-2-2782-9636 Fax: 886-2-2782-7128 (International sales hotline) Holtek Semiconductor (Hong Kong) Ltd. RM.711, Tower 2, Cheung Sha Wan Plaza, 833 Cheung Sha Wan Rd., Kowloon, Hong Kong Tel: 852-2-745-8288 Fax: 852-2-742-8657 Copyright O 2000 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
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April 11, 2000

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