HT12D/HT12F
212 Series of Decoders
Features Operating voltage: 2.4V~12V Built-in oscillator needs only 5% resistor Low power and high noise immunity CMOS Valid transmission indicator technology Easy interface with an RF or an infrared transmission Low standby current medium Capable of decoding 12 bits of information Minimal external components Binary address setting Pair with Holtek¢s 212 series of encoders Received codes are checked 3 times 18-pin DIP, 20-pin SOP package Address/Data number combination
-HT12D: 8 address bits and 4 data bits
-HT12F: 12 address bits only Applications Burglar alarm system Car alarm system Smoke and fire alarm system Security system Garage door controllers Cordless telephones Car door controllers Other remote control systems General Description
The 212 decoders are a series of CMOS LSIs for remote
control system applications. They are paired with
Holtek¢s 212 series of encoders (refer to the encoder/decoder cross reference table). For proper operation, a
pair of encoder/decoder with the same number of addresses and data format should be chosen. ously with their local addresses. If no error or unmatched codes are found, the input data codes are
decoded and then transferred to the output pins. The VT
pin also goes high to indicate a valid transmission.
The 212 series of decoders are capable of decoding
informations that consist of N bits of address 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. The decoders receive serial addresses and data from a
programmed 212 series of encoders that are transmitted
by a carrier using an RF or an IR transmission medium.
They compare the serial input data three times continu-Selection Table
Function Data Address
No. No. Type HT12D 8 4 HT12F 12 0 Part No. VT Oscillator Trigger Package L Ö RC oscillator DIN active ²Hi² 18DIP, 20SOP ¾ Ö RC oscillator DIN active ²Hi² 18DIP, 20SOP Notes: Data type: L stands for latch type data output.
VT can be used as a momentary data output. Rev. 1.20 1 February 20, 2009 HT12D/HT12F
Block Diagram
O S C 2 O S C 1 O s c illa to r D iv id e r B u ffe r D IN D a ta S h ift
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