Holtek Semiconductor Inc HT12A, HT12E Datasheet

Features

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

·

V

=5V

DD

HT12A with a 38kHz carrier for infrared

·

transmission medium

Applications

Burglar alarm system

·

Smoke and fire alarm system

·

Garage door controllers

·

Car door controllers

·

General Description

The 212encoders 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

HT12A/HT12E

12

2

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

·

Car alarm system

·

Security system

·

Cordless telephones

·

Other remote control systems

·

via an RF or an infrared transmission medium
upon receipt of a trigger signal. The capability
to select a TE
trigger on the HT12A further enhances the ap­plication flexibility of the 2
The HT12A additionally provides a 38kHz car­rier for infrared systems.

trigger on the HT12E or a DATA

12

series of encoders.

Selection Table

Function

Part No.

HT12A 8 0 4

HT12E 8 4 0

Note: Address/Data represents pins that can be address or data according to the decoder require

ment.

Address

No.

Address/
Data No.

Data

Oscillator Trigger Package

No.

455kHz

resonator

RC

oscillator

1 April 11, 2000

D8~D11

TE

18 DIP
20 SOP

18 DIP
20 SOP

Carrier

Output

38kHz No

No No

Negative

Polarity

-

Block Diagram

TE trigger

HT12E

HT12A/HT12E

OSC1OSC2

TE

A0

A7

DATA trigger

HT12A

L/M B

A0

A7

O s c illa to r

12 T ra nsm ission

G a te C irc u it

AD8 AD11

X2 X1

O scillator

12 T ra nsm ission

G a te C ir c u it

3 D ivider

¸

12 C ounter &

¸

1 of 12 D ecoder

Binary D etector

576 D ivider

¸

12 C ounter &

¸

1 of 12 D ecoder

Binary D etector

D ata Select

& Buffer

Sync.

Circuit

VDD VSS

D ata Select

& Buffer

Sync.

Circuit

DOUT

DOUT

D8 D11

VDD

VSS

Note: The address data pins are available in various combinations (refer to the address/data table).

2 April 11, 2000

Pin Assignment

HT12A/HT12E

8-A ddress
4-D ata

1

A0

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

VSS

HT12A

18 D IP

8-A ddress
4-D ata

NC

18

VDD

17

DOUT

16

X1

15

X2

14

L/M B

13

D11

12

D10

11

D9

10

D8

A0

A1

A2

A3

A4

A5

A6

A7

VSS

20

1

2

3

4

5

6

7

8

9

10

NC

19

VDD

18

DOUT

17

X1

16

X2

15

L/M B

14

D11

13

D10

12

D9

11

D8

HT12A

20 S O P

8-A ddress
4-A ddress/D ata

1

A0

A1

A2

A3

A4

A5

A6

A7

VSS

18

2

17

3

16

4

15

5

14

6

13

7

12

8

11

9

10

H T 1 2 E

1 8 D IP

VDD

DOUT

OSC1

OSC2

TE

AD11

AD10

AD9

AD8

Pin Description

Pin Name I/O

A0~A7 I

AD8~AD11 I

D8~D11 I

DOUT O CMOS OUT Encoder data serial transmission output

L/MB I

Internal

Connection

CMOS IN

Pull-high

(HT12A)

NMOS

TRANSMISSION

GATE

PROTECTION

DIODE

(HT12E)

NMOS

TRANSMISSION

GATE

PROTECTION

DIODE

(HT12E)

CMOS IN

Pull-high

CMOS IN

Pull-high

Description

Input pins for address A0~A7 setting
These pins can be externally set to VSS or left open

Input pins for address/data AD8~AD11 setting
These pins can be externally set to VSS or left open

Input pins for data D8~D11 setting and transmission en
able, active low
These pins should be externally set to VSS or left open
(see Note)

Latch/Momentary transmission format selection pin:
Latch: Floating or VDD
Momentary: VSS

8-A ddress
4-A ddress/D ata

NC

A0

A1

A2

A3

A4

A5

A6

A7

VSS

20

1

19

2

18

3

17

4

16

5

15

6

14

7

13

8

12

9

11

10

H T 1 2 E
2 0 S O P

NC

VDD

DOUT

OSC1

OSC2

TE

AD11

AD10

AD9

AD8

-

3 April 11, 2000

HT12A/HT12E

Pin Name I/O

TE

I

Internal

Connection

CMOS IN

Pull-high

Description

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

VDD I

¾

¾

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

TRANSM ISSIO N

GATE

CMOS IN
Pull-high

CMOS OUT OSCILLATOR 1

EN

OSC1

OSC2

OSCILLATOR 2

X1 X2

NMOS TRANSMISSION GATE

PROTECTION DIODE

V

DD

Absolute Maximum Ratings

Supply Voltage (HT12A) ..............-0.3V to 5.5V

Input Voltage....................V

-0.3 to VDD+0.3V

SS

Operating Temperature...............-20°Cto75°C

Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maxi

mum Ratings² 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 expo
sure to extreme conditions may affect device reliability.

Supply Voltage (HT12E) ...............-0.3V to 13V

Storage Temperature.................-50°Cto125°C

4 April 11, 2000

-

-

Electrical Characteristics

HT12A/HT12E

HT12A

Symbol Parameter

V

DD

I

STB

I

DD

I

DOUT

V

IH

V

IL

R

DATA

Operating Voltage

Standby Current

Operating Current

Output Drive Current 5V

²H² Input Voltage ¾¾

²L² Input Voltage ¾¾

D8~D11 Pull-high
Resistance

HT12E

Symbol Parameter

V

I

STB

I

DD

I

DOUT

V

V

f

OSC

R

Operating Voltage

DD

Standby Current

Operating Current

Output Drive Current 5V

²H² Input Voltage ¾¾

IH

²L² Input Voltage ¾¾

IL

Oscillator Frequency 5V

TE Pull-high Resistance 5V

TE

Test Conditions

V

DD

Conditions

¾¾

3V

Oscillator stops

5V

3V

No load

=455kHz

f

OSC

5V

=0.9VDD(Source)

V

OH

=0.1VDD(Sink)

V

OL

=0V

V

5V

DATA

Test Conditions

V

DD

Conditions

¾¾

3V

Oscillator stops

12V

3V

No load

=3kHz

f

OSC

12V

=0.9VDD(Source)

V

OH

V

=0.1VDD(Sink)

OL

=1.1MW¾3¾

R

OSC

V

=0V

TE

Ta=25°C

Min. Typ. Max. Unit

2.4 3 5 V

DD

0.1 1

0.1 1

200 400

400 800

¾

V

¾

¾

DD

0.2V

150 300

mA

mA

DD

kW

¾

¾

¾

¾

-1 -1.6 ¾

2 3.2

0.8V

0

¾

Ta=25°C

Min. Typ. Max. Unit

2.4 5 12 V

¾

¾

¾

¾

-1 -1.6 ¾

1 1.6

0.8V

0

0.1 1

24

40 80

150 300

¾

DD

¾

¾

V

0.2V

mA

mA

mA

mA

mA

mA

DD

DD

kHz

¾

1.5 3

MW

mA

mA

mA

mA

V

V

V

V

5 April 11, 2000

HT12A/HT12E

Functional Description

Operation

12

The 2
(TE
transmission enable (TE
coder output completes its final cycle and then stops as shown below.

series of encoders begin a 4-word transmission cycle upon receipt of a transmission enable

for the HT12E or D8~D11 for the HT12A, active low). This cycle will repeat itself as long as the

or D8~D11) is held low. Once the transmission enable returns high the en

TE

< 1 w ord

Encoder

DOUT

4 w ords

Transm itted

C ontinuously

4 w ords

Transmission timing for the HT12E

D8~D11

Key-in

Encoder

DOUT

< 1 w ord

1 w ord

T ra n s m itte d

C ontinuously

w ith 38kH z carrier

1 w ord

-

D8~D11

Key-in

Encoder

DOUT

Transmission timing for the HT12A (L/MB=Floating or VDD)

(all data=1)

7 w ords

1 w o r d

1 w ord

< 1 w ord

7 w ords

(all data=1)

Transm itted

C ontinuously

Transmission timing for the HT12A (L/MB=VSS)

6 April 11, 2000

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 trans
mission 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 ²1² data code.

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

Each programmable address/data pin can be externally set to one of the following two logic states as
shown below.

f

OSC

"O n e"

"Z ero"

Address/

Data Bit

Address/Data bit waveform for the HT12E

f

OSC

"O n e"

Data Bit

"Z ero"

Data Bit

"O n e"

Address B it

"Z ero"

Address B it

38kHz
carrier

Address/Data bit waveform for the HT12A

7 April 11, 2000

HT12A/HT12E

The address/data bits of the HT12A are transmitted with a 38kHz carrier for infrared remote con
troller flexibility.

Address/data programming (preset)

The status of each address/data pin can be individually pre-set to logic ²high² or ²low². If a transmis
sion-enable signal is applied, the encoder scans and transmits the status of the 12 bits of ad
dress/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

VDD A0 A1 A2 A3 A4 A5 A6 A7 VSS AD 8 AD9 AD10 AD11

V

DD

TE

Transm ission

m edium

-

-

-

The transmitted information is as shown:

Pilot

A10A21A30A40A50A61A71AD81AD91AD101AD11

&

Sync.A01

VSS

0

8 April 11, 2000

HT12A/HT12E

Address/Data sequence

The following provides the address/data sequence table for various models of the 2
encoders. The correct device should be selected according to the individual address and data require
ments.

Address/Data Bits

Part No.

01234567891011

HT12A A0 A1 A2 A3 A4 A5 A6 A7 D8 D9 D10 D11

HT12E A0 A1 A2 A3 A4 A5 A6 A7 AD8 AD9 AD10 AD11

Transmission enable

For the HT12E encoders, transmission is enabled by applying a low signal to the TE
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 ²Application cir
cuits²).

·

Error: AD8~AD11 pins input voltage > VDD+0.3V

12

series of

pin. For the

-

-

OSC2

OSC1

TE

VSS

H T12E

VDD

AD11

AD10

AD9

AD8

12V

9 April 11, 2000

·

Error: The IC¢s power source is activated by pins AD8~AD11

HT12A/HT12E

12V

Flowchart

·

HT12A

No

Power on

Standby m ode

D ata enable?

Yes

D a ta w ith c a r rie r

serial output

OSC2

OSC1

TE

VSS

HT12E

VDD

AD11

AD10

AD9

AD8

·

HT12E

No

Power on

Standby m ode

Transm ission

enabled ?

Yes

4 data w ords

transm itted

D ata still enabled ?

No

L/M B =G N D ?

No

Send the
la s t c o d e

Yes

Yes

Send

7 tim e s fo r

²1²

all of the data codes

Note: D8~D11 are transmission enables of the HT12A.

is the transmission enable of the HT12E.

TE

10 April 11, 2000

No

Transm ission

s till enabled

Yes

4 data w ords

transm itted

continuously

Oscillator frequency vs supply voltage

OSC

f

(S cale)

7.00

6.00

5.00

4.00

(3kH z)3.00

HT12A/HT12E

OSC

(W)

R

470k

510k

560k

620k

680k

750k

820k

910k

1.0M

1.2M

2.00

1.00

2 3 4

The recommended oscillator frequency is f

5 6 7 8 9 10 11 12 13

(decoder) @ 50 f

OSCD

1

@

3

(HT12E encoder)

OSCE

(HT12A encoder)

f

OSCE

1.5M

2.0M

VDD (V D C )

11 April 11, 2000

Application Circuits

100

10k

455k

W

8050

W

W

10M

100pF

W

100pF

V

DD

1

A0

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

VSS

VDD

DOUT

X1

X2

L/M B

D11

D10

D9

D8

18

17

16

15

14

13

12

11

10

HT12A

Note: Typical infrared diode: EL-1L2 (KODENSHI CORP.)

Typical RF transmitter: JR-220 (JUWA CORP.)

HT12A/HT12E

Transm itter C ircuit

1

A0

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

VSS

VDD

DOUT

OSC1

OSC2

TE

AD11

AD10

AD9

AD8

HT12E

V

DD

18

17

16

R

OSC

15

14

13

12

11

10

12 April 11, 2000

HT12A/HT12E

Holtek Semiconductor Inc. (Headquarters)

No.3 Creation Rd. II, Science-based Industrial Park, Hsinchu, Taiwan, R.O.C.
Tel: [phone]
Fax: [phone]

Holtek Semiconductor Inc. (Taipei Office)

5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C.
Tel: [phone]
Fax: [phone]
Fax: [phone] (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: [phone]
Fax: [phone]

Copyright Ó 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 pres
ent 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.

13 April 11, 2000

-