器件名称:
CD54HC4059F3A
功能描述:
High-Speed CMOS Logic CMOS Programmable Divide-by-N Counter
文件大小:
209.98KB 共12页
简 介:
CD54HC4059, CD74HC4059 Data sheet acquired from Harris Semiconductor SCHS206B February 1998 - Revised May 2003 High-Speed CMOS Logic CMOS Programmable Divide-by-N Counter Description 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 Ka, Kb and Kc 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. For example, in the ÷2 mode, only one flip-flop is needed in the first counting section. Therefore the last counting section has three flip-flops that can be preset to a maximum count of seven with a place value of thousands. If ÷10 is desired for the first section, Ka is set “high”, Kb “high” and Kc “low”. Jam inputs J1, J2, J3, and J4 are used to preset the first counting section and there is no last counting section. The……
