CD4017 Johnson Counter

The CD4017B or CD4017 Johnson Counter is a 5-stage Johnson decade counter with ten spike-free decoded active HIGH outputs (Ooto O9), an active LOW output from the most significant flip-flop (O5-9), active HIGH and active LOW clock inputs (CP0, CP1) and an overriding asynchronous master reset input (MR). The counter is advanced by either a LOW to HIGH transition at CP0whileCP1is LOW or a HIGH to LOW transition at CP1while CP0is HIGH (see also function table). When cascading counters, the O5-9output, which is LOW while the counter is in states 5, 6, 7, 8, and 9, can be used to drive the CP0input of the next counter.A HIGH on MR resets the counter to zero(Oo=O5-9= HIGH; O1to O9= LOW) independent of the clock inputs (CP0, CP1). Automatic code correction of the counter is provided by an internal circuit: following any illegal code the counter returns to a proper counting mode within 11 clock pulses. Schmitt-trigger action in the clock input makes the circuit highly tolerant to slower clock rise and fall times. Click for the Data Sheet