SS421L

 1st Level Hall-Effect Sensors

	SS421L Adjustable Hall-effect Underspeed Detector (Active - Low); SIP-4 radial lead IC package
Actual product appearance may vary.

Features	Potential Applications
Features Wide temperature ranges for design flexibility Temperature compensated for consistent operation with low-cost magnets Bipolar operation for easy RPM counting using ring magnets Built-in timing circuit greatly simplifies and reduces the cost of PC board design Speed trip point adjustable with external resistor and capacitor	Potential Applications Under-speed detection for fans Conveyors Motor control Power-up fault failure filter in motor start-up

Description

The SS421 Series Adjustable Hall-effect Under-speed Detectors are designed to monitor fan or motor performance. This temperature-compensated, Hall-effect IC contains a timing circuit and logic, that senses magnetic input frequency. The internal circuitry contains a timer so that one or two pulses at a slower repetition rate than the set point do not produce an unwanted output. A small amount of hysteresis has been built into the output so that operation right at the set point does not result in a chattering output. The user simply provides an external resistor and capacitor combination to select the RPM trip point that will fit the particular application.