CD40161BE (TEXAS INSTRUMENTS)

The CD40161BE is a 4-bit CMOS synchronous programmable Binary Counter with asynchronous clear. The clear function of the CD40161B is asynchronous and a low level at the CLR input sets all four outputs low regardless of the state of the clock, LOAD or enable inputs. A low level at the LOAD input disables the counter and causes the output to agree with the setup data after the next clock pulse regardless of the conditions of the 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 two count-enable inputs and a carry output (COUT). Counting is enabled when both PE and TE inputs are high. The TE input is fed forward to enable COUT. This enabled output produces a positive output pulse with duration approximately equal to the positive portion of the Q1 output. This positive overflow carry pulse can be used to enable successive cascaded stages.