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.
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 continuously 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.
Operating voltage: 2.4V~12V
Low power and high noise immunity CMOS technology
Low standby current
Capable of decoding 12 bits of information
Binary address setting
Receired 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
Pair with Holtek’s 212 series of encoders
18-pin DIP, 20-pin SOP package