4000-series IC reference

4017 (Decade counter)

The 4017 is a decade counter with 10 individual outputs.

1. 5
2. 1
3. 0
4. 2
5. 6
6. 7
7. 3
8. Ground (V’SS)
9. 8
10. 4
11. 9
12. Carry out (CARRY)
13. Clock inhibit (~CE)
14. Clock (CLK)
15. Reset (RESET)
16. Supply voltage (V’DD)

The device starts with all output pins low, other than output pin 0 (physical pin 3), which is high. If ~CE is low, each transition of CLOCK from low to high will bring the active output pin low and bring high the next output pin in the sequence.

The CARRY pin is high when the active output is 0/1/2/3/4, and is low when the active output is 5/6/7/8/9. This has the effect that CARRY will transition from low to high when the output rolls over from 9 to 0, and so can be chained to the CLOCK pin on a separate device.

Transitioning the RESET pin from low to high will reset the internal counter, bringing the active output pin low and bringing output pin 0 high.