3
18 
Series of Decoders
Selection Table
Function
Address
No.
Data
VT Oscillator Trig ger Package
Item No. Type
HT602L 12 2 L
√
RC oscillator DIN active “Hi” 20 DIP/20 SOP
HT604L 10 4 L
√
RC oscillator DIN active “Hi” 20 DIP/20 SOP
HT605L 9 5 L
√
RC oscillator DIN active “Hi” 20 DIP/20 SOP
HT611 14 0 —
√
RC oscillator DIN active “Hi” 20 DIP/20 SOP
Features
•
Operating voltage: 2.4V~12V
•
Low power and high noise immunity CMOS 
technology
•
Low standby current
•
Capable of decoding 18 bits of information
•
Pairs with HOLTEK’s 318 series of encoders
•
8~18 address pins
•
0~8 data pins
•
Trinary address setting
•
Two times of receiving check
•
Built-in oscillato r needs only a 5% resistor
•
Valid transmission indictor
•
Easily interface with an RF or an infrared 
transmission medium
•
Minimal external components
General Description
The 318 decoders are a series of CMOS LSIs for 
remote control system applications. They are 
paired with the 3
18
 series of encoders. For 
proper operation a pair of encoder/decoder pair 
with the same number of address and data 
format should be selected (refer to the encoder/decoder cross reference tables).
The 3
18
 series of decoders receives serial address and data from that series of encoders that 
are transmitted by a carrie r using an R F or a n 
IR transmission medium. It then compares the 
serial input data twice continuously with its 
local address. If no errors or unma tched codes
are encountered, the input data codes are decoded and then transferred to the outp ut pins. 
The VT pin also goes high to indicate a valid 
transmission.
The 3
18
 decoders are capable of decoding 18 bits 
of information that consists of N bits of address 
and 18–N bits of data. To meet various applications they are arranged to provi de a nu mber of 
data pins whose range is from 0 to 8 and an 
address pin whose range is from 8 to 18. In 
addition, the 3
18
 decoders provide various combinations of address/d ata number in different 
packages.
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
1 2nd Oct ’97