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LMP7300: LMP7300 for the selection questions

Mickey Zhang
Genius 12080 points
Part Number: LMP7300
Other Parts Discussed in Thread: LMV393-N, TLV1701, TLV7011, TLV3201, LMV393, LMV7239

Hi team,

The customer has two questions for LMP7300.

Q1: The datasheet shows ""For precise level detection applications, TI recommends symmetric hysteresis values less than 5 mV to 10 mV." 

on page 12. For the customer's application, the hysteresis value is 100mV. Can LMP7300 meet his requirement? 

If not ,would you recommend a suitable device? How to determine the hysteresis value for the comparator devices?

Q2: The datasheet shows "By optimizing overdrive, the pullup resistor and capactive load fault update rates of 200 kHz to

250 kHz or greater can be achieved." on page 10. Now the customer's switching frequency is higher than 500KHZ. 

Can LMP7300 meet his requirement? If not ,would you recommend a suitable device?

Best Wishes,
Mickey Zhang
Asia Customer Support Center
Texas Instruments

  • 0
    TI__Guru 53696 points

    Hi Mickey,

    The maximum recommended hysteresis is 110mV. 100mV is towards the high end, but should work.

    The LMP7300 was primarily designed for battery or supply line monitoring applications.

    It will definitely not support >500kHz. I really doubt it would even make 200kHz - you would need volts of overdrive.

    Also note the LMV7300 input range does not include ground - so make sure the customer input voltage range is correct. The valid input range is 1V above ground up to V+.

    Hysteresis can be added to any comparator. Many of the datasheets contain a section on adding Hysteresis. See the LMV393-N datasheet applications section as an example, or Application Note AN-74.

    In general, the maximum "toggle rate" of the comparator is 1 / ( 2 *response time). So for 1MHz (to give some margin), you would need a comparator with a response time faster than 500ns. Capacitive loading of the output also affects the maximum toggle rate - so keep output cap loading low.

    Obviously, the 5-15us of the LMP7300 is not fast enough for 500kHz. This is expected as the LMP7300 was designed for low standby power, so speed is sacrificed for power savings.

    The aforementioned LMV393 should work, or better the TLV3201, TLV1701, LMV7239 or TLV7011 family.