What should I do with the CLEAR pin on startup of the MAX834?

Once low, OUT stays low until 1) IN is above the threshold voltage AND 2) the latched output is reset. When IN is first applied (say, at powerup), the latch will start with the output low and will need to be cleared. To clear the latch the CLEAR pin needs to see a low-high-low transition with at least 1µs high duration. Please note that this part does not have rail-to-rail inputs or outputs, due to the internal structure the comparator could saturate and be unable to switch if IN = Vcc. Please follow the Typical Operating Circuit on page one of the datasheet, which includes a resistor-divider. Aim to keep Vcc greater than IN by at least 0.6V.

For MAX834 and MAX835, what is the state of the /OUT pin upon start-up?

For MAX834 and MAX835 start-up, the /OUT pin state is dependent on IN once VCC rises above the minimum operating voltage threshold (i.e. 2.5V). Once VCC rises above the minimum operating voltage, there is a 35us glitch immunity period to prevent any noise from asserting /OUT. The part will not assert /OUT until after this period. If IN>1.204V after the glitch immunity period, then /OUT will be pulled high. Otherwise, /OUT is pulled low.

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MAX834EUK+: FAQ