Description
HT12D is a CMOS technology-based 12-bit Decoder. It is generally used with RF communication system applications. 12-bit Decoders can decode up to 2^12 encoded data which is coming from the RF transmitter. This decoded data consists of 8 address bits and 4 data bits. For proper communication, HT12D is should be used with HT12E in the same address and data formate. This device consists of one data input pin that receives the encoded data from the RF receiver pin. Two oscillators pin (OSC1, OSC2) can decide the oscillation frequency of the Decoder by using an oscillator resistor. On proper communication, the Valid Transmission pin (VT) goes High.
The HT12D ICs have an operating range of VCC from 2.4 V to 12 V. Maximum current consumption is 0.4 mA through Icc and output sink and source current is 1.6 mA. The recommended operating voltage is 5 V.
Working
HT12D decoder will be in standby mode initially, i.e., the oscillator is disabled and a HIGH on DIN pin activates the oscillator. Thus the oscillator will be active when the decoder receives data transmitted by an encoder. The device starts decoding the input address and data. The decoder matches the received address three times continuously with the local address given to pin A0 – A7. If all matches, data bits are decoded and output pins D8 – D11 is activated. This valid data is indicated by making the pin VT (Valid Transmission) HIGH. This will continue till the address code becomes incorrect or no signal is received.
Pin Configuration
| Address Pin (A[0:7]) | 1, 2, 3, 4, 5, 6, 7, 8 |
| Data Pin (D[8:11]) | 10, 11, 12, 13 |
| Oscillator I/O Pin (OSC1, OSC2) | 16, 15 |
| Valid Transmission Pin (VT) | 17 |
| Data Input Pin (DIN) | 14 |
| Power Supply (VDD) | 18 |
| Ground (VSS) | 9 |
Features
- 12-bit Decoder IC to be used with HT12E
- Decoded data has 4 Data bits and 8 Address bits (8+4=12-bits)
- Commonly used for RF and IR wireless transmission
- Operating Voltage 5V
- Low standby current of 0.1uA at Vcc=5V
- Available in 16-pin DIP, 20-pin SOP
Application
- 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
Specification
| Operating Voltage Range | 2.4 V to 12 V |
| Technology | CMOS |
| Package | DIP−18 |
| Output Current | 1.6 mA |
| Powering Current | 0.4 mA |
| Temperature Range | -50 °C - 125 °C |
Pin Description
| Pin 1 - 8 | These are the 8-bit address bits, which are used to protect your data. We should set the bits in the same pattern on Encoder and Decoder IC to pair them |
| Pin 9 | Connected to the Ground of the circuit |
| Pin 10 - 13 | These four pins are used to obtain the data bits by decoding the data from the HT12E IC |
| Pin 14 | The Encoded 12-bit output data obtained from HT12E has to be given here |
| Pin 14 & 15 | The IC has a built-in oscillator. This oscillator can be used by connecting these two pins through a 1M Resistor |
| Pin 18 | This pin powers the IC should use the only 5V |
| Pin 17 | This pin will go high when data is received. It is not mandatory to use it |