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LMV393-N: Unused Input/Output Pin

Part Number: LMV393-N
Other Parts Discussed in Thread: LMV393, LM393B, LM393

Hi team,

Would you let me know how to treat unused IN and OUT pins (5, 6 and 7)?

Our customer traditionally input pins are tied to GND directly and output pin is left open. But our application report below describes "Do Not Connect Inputs Directly to Ground". It include LM393B but LMV393 is not included. Does the description apply to LMV393?



  • Hello Hideki,

    The LMV393 is basically a low voltage (5V) version of the LM393, so the unused input advice in the appnote still applies.

    As mentioned in the appnote, tying both inputs directly to GND can cause oscillations under some conditions. Since the output is an open collector, oscillations may go unnoticed. What may be noticed is a few percent increase in supply current if the comparator channel internally toggles.

    The LMV393 has a little more protection on the inputs, so you can directly ground one input. But the input pin should be grounded to the same copper patch as the GND pin (pin 4).

    The other input should be tied to a voltage source within the legal input voltage range (0V to Vcc-1V). Setting the output high or low makes no real applicable difference. One possible voltage source is to tap the reference voltage on the other channel.

    It is also possible to use the large resistor method on the un-grounded input to use the bias current to create a small voltage.

    And I recommend leaving the output open - that also allows you to easily replace the LMV393 with a push-pull output device if future substitutions are necessary.