Encoder and Decoder Pairs

• Operating Temperature Range:

TA = – 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:

ML145026 = 2.5 to 18 V*

ML145027, ML145028 = 4.5 to 18 V

• For Infrared Applications, See Application Note AN1016/D

These devices are designed to be used as encoder/decoder pairs in remote control applications.

The ML145026 encodes nine lines of information and serially sends this information upon receipt of a transmit enable (TE) signal. The nine lines may be encoded with trinary data (low, high, or open) or binary data (low or high). The words are transmitted twice per encoding sequence to increase security

The ML145027 decoder receives the serial stream and interprets five of the trinary digits as an address code. Thus, 243 addresses are possible. If binary data is used at the encoder, 32 addresses are possible. The remaining serial information is interpreted as four bits of binary data. The valid transmission (VT) output goes high on the ML145027 when two conditions are met. First, two addresses must be consecutively received (in one encoding sequence) which both match the local address. Second, the 4 bits of data must match the last valid data received. The active VT indicates that the information at the Data output pins has been updated.

The ML145028 decoder treats all nine trinary digits as an address which allows 19,683 codes. If binary data is encoded, 512 codes are possible. The VT output goes high on the ML145028 when two addresses are consecutively received (in one encoding sequence) which both match the local address

MAXIMUM RATINGS* (Voltages Referenced to VSS)