Min/Max circuit for analog convolutional decoders

A novel minimum or maximum compare and select circuit is presented in this brief for use in analog convolutional decoders. Based on voltage difference circuits coupled to a decision circuit the proposed circuit can differentiate voltages of 10-mV differences in the simple configuration or 5 mV in an improved configuration. Simulation results indicate an operational speed of 100 Mbits/s of a 3.3-V supply, which is comparable to similar current based, compare and select circuits. In addition, the proposed circuit has only two devices stacked between its rails in contrast to most voltage/current based compare and select circuits with three or more devices. The circuit is, therefore, capable of operation at low supply voltages making it attractive for low power applications.