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Piccolo Analog Comparator

Mars G
Intellectual 400 points

I investigate the specifications of Piccolo F28035 Analog Comparator.

The comparator response time is specified in the TMS320F2803x Datasheet(SPRS584i) as follows.

   Section 6.11.12 --- "Comparator response time to PWM Trip Zone (Async) is 30ns(TYP)"

But a test condition such as overdrive voltage is not specified.

Please tell me the overdrive specifications of analog comparator.

 

Thanks

 

  • 0
    TI__Guru* 84570 points

    Mars,

    Can you give some more information on what you mean by overdrive voltage?  The spec in the datasheet is refering to when the comparator inputs have crossed to when the output reaches the Trip Zone.  There is additional spec in the trip zone that specifies when activated how long until the PWM output goes high Z.

     

    Matt

  • 0 in reply to MatthewPate
    Intellectual 400 points

    Hello Matt,

    Thanks for your reply.

    The overdrive voltage which I mean is as follows.

    When the comparator input_A is 0V and input_B is 1V, if the voltage of input_A is increased from 0V to over 1V, then a comparator output will change (reaches Trip Zone).

    But I think that the response time (delay time until output change) has a difference in case where input_A is raise to 1.1V and raise to 2V

    Therefore I would like to know how much large voltage (ex. 100 mV or 1V) is given the comparator in testing the response time (TYP 30ns) of the spec.

     

    Thank you

  • 0 in reply to Mars G
    TI__Guru 60865 points

    Mars,

    I think this spec. was probably tested using full overdrive; the comparator input was changed from 0 to 3.3V or from 3.3V to 0.   

  • 0 in reply to Devin Cottier
    Intellectual 400 points

    Devin,

    I understood.

    Thank you so much.

     

    Mars

  • 0 in reply to MatthewPate
    Prodigy 80 points

    Hello Matt,

           I have a question about Piccolo analog comparator too.

           If I accommodate one external analog input and using the internal DAC reference for the other input,

           specifically, when the comparator input_A is 512 in digital (VDDA-VSSA=3.3V), input_B reach 1.65V,

           How long  until the comparator output change ?

           The response time still equal 30ns or it depends ?