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Frequency divider circuit needed

bob benson
Prodigy 60 points

Other Parts Discussed in Thread: SN74LVC1G175

I have a frequency divider circuit to divide by 2 using the d-flip flop SN74LVC1G80YZPR. The is a BGA device and I would like to change to a SON (small outline no lead) package. I then found the d-flip flop SN74LVC1G175DRY. With the SN74LVC1G80YZPR I can tie the Q not  pin back to the D input and drive the clock input with the frequency that I want to divide. Then the Q not pin will be 1/2 the input frequency. But the SN74LVC1G175DRY has only a Q output and does not have a Q not output. It also has an asynchronous clear input. Can I tie the asynchronous clear input. high and tie the Q output back to the D input and drive the clock input with the frequency I want to divide to get 1/2 the frequency at the Q output? If not what would you suggest? I need something that does not take up much space.

Thanks,

Bob

  • 0
    TI__Guru 64940 points

    In reviewing the truth table of the SN74LVC1G175, Table 1 of the datasheet, if the asynchronous CLR is asserted (ie. driven low), then all other inputs including CLK and D are don't cares, which means the Q output will remain low.  Therefore, I don't believe your suggestion of connecting the Q output to the CLR input is going to deliver the results you want.  You will need to use an inverter device between the Q output and D input.

    Would the SN74AUP1G80 work for your?  I don't know what your operating voltage requirements are, but I would suggest taking a look at this.