mc145027 pdf

These devices are designed to be used as encoder/decoder pairs in remotecontrol applicaTIons.The MC145026 encodes nine lines of informaTIon and serially sends thisinformaTIon upon receipt of a transmit enable (TE) signal. The nine lines may beencoded with trinary data (low, high, or open) or binary data (low or high). Thewords are transmitted twice per encoding sequence to increase security.The MC145027 decoder receives the serial stream and interprets five of thetrinary digits as an address code. Thus, 243 addresses are possible. If binarydata is used at the encoder, 32 addresses are possible. The remaining serialinformaTIon is interpreted as four bits of binary data. The valid transmission (VT)output goes high on the MC145027 when two conditions are met. First, twoaddresses must be consecutively received (in one encoding sequence) whichboth match the local address. Second, the 4 bits of data must match the lastvalid data received. The active VT indicates that the information at the Dataoutput pins has been updated.The MC145028 decoder treats all nine trinary digits as an address whichallows 19,683 codes. If binary data is encoded, 512 codes are possible. The VToutput goes high on the MC145028 when two addresses are consecutivelyreceived (in one encoding sequence) which both match the local address.• Operating Temperature Range: – 40 to + 85°C• Very–Low Standby Current for the Encoder: 300 nA Maximum @ 25°C• Interfaces with RF, Ultrasonic, or Infrared Modulators and Demodulators• RC Oscillator, No Crystal Required• High External Component Tolerance; Can Use ± 5% Components• Internal Power–On Reset Forces All Decoder Outputs Low• Operating Voltage Range: MC145026 = 2.5 to 18 V*MC145027, MC145028 = 4.5 to 18 V• Low–Voltage Versions Available:SC41343 = 2.8 to 10 V Version of the MC145027SC41344 = 2.8 to 10 V Version of the MC145028• For Infrared Applications, See Application Note AN1016/D