wuxi i-乐鱼全站app网页版

aip74hc/hct162
presettable synchronous bcd decade counter; synchronous reset

the aip74hc/hct162 is a synchronous presettable decade counter with an internal look-ahead carry. synchronous operation is provided by having all flip-flops clocked simultaneously on the positive-going edge of the clock (cp). the outputs (q0 to q3) of the counters may be preset high or low. a low at the parallel enable input (pe()) disables the counting action and causes the data at the data inputs (d0 to d3) to be loaded into the counter on the positive-going edge of the clock. preset takes place regardless of the levels at count enable inputs (cep and cet). a low at the master reset input (mr()) sets q0 to q3 low after the next positive-going transition on the clock input (cp). this action occurs regardless of the levels at input pinspe(), cet and cep. this synchronous reset feature enables the designer to modify the maximum count with only one external nand gate. the look-ahead carry simplifies serial cascading of the counters. both cep and cet must be high to count. the cet input is fed forward to enable the terminal count output (tc). the tc output thus enabled will produce a high output pulse of a duration approximately equal to a high output of q0. this pulse can be used to enable the next cascaded stage. inputs include clamp diodes. this enables the use of current limiting resistors to interface inputs to voltages in excess of vcc.

the cp to tc propagation delay and cep to cp set-up time determine the maximum clock frequency for the cascaded counters according to the following formula:

fmax=1/(tp(max)(cp to tc) tsu(cep to cp))


  • main features product

  • product documents

  • input levels:

    for aip74hc162: cmos level

    for aip74hct162: ttl level

  • synchronous counting and loading

  • 2 count enable inputs for n-bit cascading

  • synchronous reset

  • positive-edge triggered clock

  • specified from -40℃ to 105℃

  • packaging information: dip16/sop16/tssop16


note: please contact us if you need samples or other docunmets>>

中文文档下载
英文文档下载
网站地图