Intended for monitoring low-voltage levels in battery-operated systems, the MIC841 and MIC842 ultra-low-power comparators feature on-chip precision voltage references with 1.25% accuracy. These Micrel Semiconductor units also incorporate hysteresis to suppress noise.
Users can set the MIC841's hysteresis from millivolts to volts with three external resistors to set upper and lower trip thresholds. The difference between these threshold voltages determines the hysteresis voltage. The MIC842, which uses two external resistors to set the lower threshold voltage, incorporates fixed internal hysteresis.
Both come with active-high or active-low inputs and with push-pull outputs. Active-low versions are available with open-drain outputs that let users wire-OR devices together. Regardless of supply voltage, output can be pulled up to 6 V.
These devices are immune to very short input transients. Housed in miniature five-lead SC-70 packages, they operate from 1.5 to 5.5 V and consume only 1.5 µA. Both models cost $1.10 each in 1000-piece quantities.
Micrel Semiconductor, 1849 Fortune Dr., San Jose, CA 95131; (408) 435-2406; www.micrel.com.
