CD54HC4059,CD74HC4059,PDF(High

The ’HC4059 are high-speed silicon-gate devices that are pin-compatible with the CD4059A devices of the CD4000B series. These devices are divide-by-N down-counters that can be programmed to divide an input frequency by any number "N" from 3 to 15,999. The output signal is a pulse one clock cycle wide occurring at a rate equal to the input frequency divide by N. The down-counter is preset by means of 16 jam inputs.

The three Mode-Select Inputs K_a,K_b and K_c determine the modulus ("divide-by" number) of the first and last counting sections in accordance with the truth table. Every time the first (fastest) counting section goes through one cycle, it reduces by 1 the number that has been preset (jammed) into the three decades of the intermediate counting section an the last counting section, which consists of flip-flops that are not needed for opening the first counting section.