Re: Is anybody using NE521 comparators?

On 9/25/24 19:19, Liz Tuddenham wrote:

Jean-Pierre Coulon <coulon@cacas.pam.oca.eu> 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?

 If the strobe pins are high, the output will be undefined.
 

That's not so. The NE521 has no latch of flipflop. What they call
strobes are actually inputs to NAND gates. If any of the strobes
are low, the associated output(s) will be forced high.
The output is a traditional Schottky TTL gate. If the OP sees
something in between a definite high or low, it's probably
oscillating. That could be because one or both of the comparator
inputs are driven from a too-high impedance, or it could be
feedback due to poor layout, or it could be poor or missing
power supply decoupling, or something else yet.
In summary, let's wait until he shows us what he did.
Jeroen Belleman
P.S. Half of the equivalent schematic in the datasheet is
nonsense.