2
12
Series of Decoders
Features
·
·
·
·
·
·
·
Operating voltage: 2.4V~12V
Low power and high noise immunity CMOS
technology
Low standby current
Capable of decoding 12 bits of information
12
Pair with Holtek¢s 2 series of encoders
Binary address setting
Received codes are checked 3 times
·
·
·
·
·
Address/Data number combination
-
HT12D: 8 address bits and 4 data bits
-
HT12F: 12 address bits only
Built-in oscillator needs only 5% resistor
Valid transmission indicator
Easy interface with an RF or an infrared
transmission medium
Minimal external components
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 2 decoders are a series of CMOS LSIs for
remote control system applications. They are
12
paired with Holtek¢s 2 series of encoders (re-
fer to the encoder/decoder cross reference ta-
bl e ). For p rop er oper a ti on, a pa ir of
encoder/decoder with the same number of ad-
dresses and data format should be chosen.
The decoders receive serial addresses and data
12
from a programmed 2 series of encoders that
are transmitted by a carrier using an RF or an
IR transmission medium. They compare the se-
rial input data three times continuously with
12
their local addresses. If no error or unmatched
codes are found, the input data codes are de-
coded and then transferred to the output pins.
The VT pin also goes high to indicate a valid
transmission.
The 2 series of decoders are capable of decod-
ing informations that consist of N bits of ad-
dress and 12-N bits of data. Of this series, the
HT12D is arranged to provide 8 address bits
and 4 data bits, and HT12F is used to decode 12
bits of address information.
12
Selection Table
Function Address
No.
Part No.
HT12D
HT12F
8
12
Data
No.
4
0
Type
L
¾
VT
Ö
Ö
Oscillator
Trigger
Package
RC oscillator DIN active
²Hi²
18 DIP/20 SOP
RC oscillator DIN active
²Hi²
18 DIP/20 SOP
Notes: Data type: L stands for latch type data output.
VT can be used as a momentary data output.
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July 12, 1999
2
12
Series of Decoders
Block Diagram
O S C 2
O S C 1
O s c illa to r
D iv id e r
D a ta S h ift
R e g is te r
L a tc h C ir c u it
D a ta
D IN
B u ffe r
D a ta D e te c to r
S y n c . D e te c to r
C o m p a ra to r
C o m p a ra to r
C o n tr o l L o g ic
T r a n s m is s io n G a te C ir c u it
B u ffe r
V T
A d d re s s
V D D
V S S
Note: The address/data pins are available in various combinations (see the address/data table).
Pin Assignment
8 -A d d re s s
4 -D a ta
A 0
A 1
A 2
A 3
A 4
A 5
A 6
A 7
V S S
9
8
7
6
5
4
3
2
1
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
1 0
V D D
V T
O S C 1
O S C 2
D IN
D 1 1
D 1 0
D 9
D 8
8 -A d d re s s
4 -D a ta
N C
1
2
3
4
5
6
7
8
9
1 0
A 0
A 1
A 2
A 3
A 4
A 5
A 6
A 7
V S S
2 0
1 9
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
N C
V D D
V T
O S C 1
O S C 2
D IN
D 1 1
D 1 0
D 9
D 8
1 2 -A d d re s s
0 -D a ta
A 0
A 1
A 2
A 3
A 4
A 5
A 6
A 7
V S S
9
8
7
6
5
4
3
2
1
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
1 0
V D D
V T
O S C 1
O S C 2
D IN
A 1 1
A 1 0
A 9
A 8
1 2 -A d d re s s
0 -D a ta
N C
1
2
3
4
5
6
7
8
9
1 0
A 0
A 1
A 2
A 3
A 4
A 5
A 6
A 7
V S S
2 0
1 9
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
N C
V D D
V T
O S C 1
O S C 2
D IN
A 1 1
A 1 0
A 9
A 8
H T 1 2 D
1 8 D IP
H T 1 2 D
2 0 S O P
H T 1 2 F
1 8 D IP
H T 1 2 F
2 0 S O P
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July 12, 1999
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12
Series of Decoders
Pin Description
Pin Name
A0~A11
D8~D11
DIN
VT
OSC1
OSC2
VSS
VDD
I/O
I
O
I
O
I
O
I
I
Internal
Connection
Description
NMOS
Input pins for address A0~A11 setting
TRANSMISSION
They can be externally set to VDD or VSS.
GATE
CMOS OUT
CMOS IN
CMOS OUT
OSCILLATOR
OSCILLATOR
¾
¾
Output data pins
Serial data input pin
Valid transmission, active high
Oscillator input pin
Oscillator output pin
Negative power supply (GND)
Positive power supply
Approximate internal connection circuits
N M O S
T R A N S M IS S IO N
G A T E
C M O S O U T
C M O S IN
O S C IL L A T O R
E N
O S C 1
O S C 2
Absolute Maximum Ratings
Supply Voltage...............................-0.3V to 13V
Input Voltage....................V
SS
-0.3
to V
DD
+0.3V
Storage Temperature.................-50°C to 125°C
Operating Temperature ..............-20°C to 75°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 de-
vice at other conditions beyond those listed in the specification is not implied and prolonged
exposure to extreme conditions may affect device reliability.
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July 12, 1999
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12
Series of Decoders
Electrical Characteristics
Symbol
V
DD
I
STB
I
DD
Parameter
Operating Voltage
Standby Current
Operating Current
Data Output Source
Current (D8~D11)
Data Output Sink
Current (D8~D11)
VT Output Source Current
VT Output Sink Current
²H²
Input Voltage
²L²
Input Voltage
Oscillator Frequency
Test Conditions
V
DD
¾
5V
12V
5V
5V
5V
5V
5V
5V
5V
Conditions
¾
Oscillator stops
No load
f
OSC
=150kHz
V
OH
=4.5V
V
OL
=0.5V
V
OH
=4.5V
V
OL
=0.5V
¾
¾
R
OSC
=51kW
Min.
2.4
¾
¾
¾
-1
1
-1
1
3.5
0
¾
Typ.
5
0.1
2
200
-1.6
1.6
-1.6
1.6
¾
¾
150
Max.
12
1
4
400
¾
¾
¾
¾
5
1
¾
Ta=25°C
Unit
V
mA
mA
mA
mA
mA
mA
mA
V
V
kHz
I
O
I
VT
V
IH
V
IL
f
OSC
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July 12, 1999
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12
Series of Decoders
Functional Description
Operation
The 2 series of decoders provides various com-
binations of addresses and data pins in differ-
12
ent packages so as to pair with the 2 series of
encoders.
The decoders receive data that are transmitted
by an encoder and interpret the first N bits of
code period as addresses and the last 12-N bits
as data, where N is the address code number. A
signal on the DIN pin activates the oscillator
which in turn decodes the incoming address
and data. The decoders will then check the re-
ceived address three times continuously. If the
received address codes all match the contents of
the decoder¢s local address, the 12-N bits of
data are decoded to activate the output pins
and the VT pin is set high to indicate a valid
transmission. This will last unless the address
code is incorrect or no signal is received.
The output of the VT pin is high only when the
transmission is valid. Otherwise it is always
low.
Output type
Of the 2 series of decoders, the HT12F has no
data output pin but its VT pin can be used as a
momentary data output. The HT12D, on the
other hand, provides 4 latch type data pins
whose data remain unchanged until new data
are received.
Part Data Address Output Operating
No. Pins Pins
Type
Voltage
HT12D
HT12F
4
0
8
12
Latch
¾
2.4V~12V
2.4V~12V
N o
12
Flowchart
The oscillator is disabled in the standby state
and activated when a logic
²high²
signal applies
to the DIN pin. That is to say, the DIN should be
kept low if there is no signal input.
P o w e r o n
S ta n d b y m o d e
D is a b le V T &
ig n o r e th e r e s t o f
th is w o r d
N o
C o d e in ?
Y e s
A d d r e s s b its
m a tc h e d ?
Y e s
S to re d a ta
N o
12
M a tc h
p r e v io u s s to r e d
d a ta ?
Y e s
N o
3 tim e s
o f c h e c k in g
c o m p le te d ?
Y e s
L a tc h d a ta
to o u tp u t &
a c tiv a te V T
A d d re s s o r
d a ta e rro r ?
Y e s
N o
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July 12, 1999
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