CD74AC161E

The CD74AC161E is a synchronous presettable Binary Counter with asynchronous reset. It features an internal carry look-ahead for application in high-speed counting. It is fully programmable, that is, it can be preset to any number between 0 and 9 or 15. Presetting is synchronous, therefore, setting up a low level at the load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of the enable inputs. The clear function is asynchronous. A low level at the clear (CLR\) input sets all four of the flip-flop outputs low, regardless of the levels of the CLK, LOAD\ or enable inputs. The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without additional gating. Instrumental in accomplishing this function are ENP, ENT and a ripple-carry output (RCO). Both ENP and ENT must be high to count and ENT is fed forward to enable RCO.