I am using an LM339 (and also LM393) in a circuit where I am powering them with a single positive voltage rail (+12V and GND). This was done so the comparator only swings between positive and gnd (I have a pullup resistor on the output).
They have been set up as comparators with the (-) pin connected to a Voltage divider set to about 2V and the input signal being fed to the (+).
Most of the time the comparator is functioning as expected but some input sources (usually square clock signals 10Vpp) are causing adjacent comparators to fire as well and generally behave erratically.
The power rails of each LM339 have a 0.1u bypass cap to filter noise.
I am wondering if the issue is caused by feeding a negative voltage to the inputs? i.e. Should I be using a diode in series to the (+) inputs to block negative DC?
They have been set up as comparators with the (-) pin connected to a Voltage divider set to about 2V and the input signal being fed to the (+).
Most of the time the comparator is functioning as expected but some input sources (usually square clock signals 10Vpp) are causing adjacent comparators to fire as well and generally behave erratically.
The power rails of each LM339 have a 0.1u bypass cap to filter noise.
I am wondering if the issue is caused by feeding a negative voltage to the inputs? i.e. Should I be using a diode in series to the (+) inputs to block negative DC?