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LMP7300 sink current

Tom Saluzzo
Expert 1280 points

Other Parts Discussed in Thread: LMP7300

What is the max sink current for the output of the LMP7300 comparator?

  • 0
    TI__Guru 71526 points

    Hi Tom,

    Although the datasheet does not provide an actual specification for the open-collector sink capability, there are several references to 10mA being the max.  For example, page 10:  The comparator employs an open collector output stage that can switch microamp loads for micropower precision threshold detection to applications requiring activating a solenoid, a lamp, or an LED. The wired-OR type output easily interfaces to TTL, CMOS, or multiple outputs, as in a window comparator application, over a range of 0.5 V to 12 V. The output is capable of driving greater than 10-mA output current and yet maintaining a saturation voltage less than 0.4 V over temperature.

    Figures 2, 3 and 4 on page 8 all plot from 0 - 10mA.  And comparator spec VCL on page 7 specifies: ILOAD = 10 mA

    Is 10mA sufficient for the application?

    ~Leonard 

  • 0 in reply to LeonardEllis
    Expert 1280 points

    No, the application is looking for 40mA source.

    So if the device states "capable of driving greater than 10-mA output current", then shouldn't the sink current be greater than 10mA?

  • 0 in reply to Tom Saluzzo
    TI__Guru 71526 points

    Hi Tom,

      I think 40mA is a stretch, and yes, the text does say "greater than 10mA" but none of the data/specifications support this. I've asked the Product Group to look at this, and it could just be someone wrote this statement but meant to say "up to 10mA"

    ~Leonard

  • 0 in reply to Tom Saluzzo
    TI__Guru 66666 points
    Hi Tom,

    The LMP7300 was designed for micropower operation, and thus has limited drive capabilities.

    Looking at the design review, I would not expect to get more than 15mA sinking. It will not do 40mA.

    The intended supply voltage was not mentioned and it will also have an effect on output drive capabilities (bipolar output). The only "guaranteed" number is 10mA at 0.4V sinking with 5V supply.

    An external pass device should be used when the load is >10mA.

    Regards,