Re: Is anybody using NE521 comparators?

On 25/09/2024 11:16 pm, Jean-Pierre Coulon wrote:

If the difference between both inputs is not a least 50 mV the output remain at about 1.5 or 2V instead of beeing close to V+ or ground. What am I doing wrong?

Getting it to oscillate faster than your oscilloscope can follow?
The NE521 is quite fast - it can get up to 55MHz - and it's not difficult to make it self-oscillate if the voltage difference between the input isn't high enough to swamp capacitative feed-through or ground loops.
I've had to crawl through circuits which were in production when a batch of faster comparators - not NE521 parts - showed up a marginal layout. And tightening up the layout didn't always keep on working.
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Bill Sloman, Sydney