SS421H

SS421H Adjustable Hall-effect

Underspeed Detector (Active - High);

SIP-4 radial lead IC package

Actual product appearance may vary.

Features

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Wide temperature ranges for design

flexibility

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Temperature compensated for

consistent operation with low-cost

magnets

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Bipolar operation for easy RPM

counting using ring magnets

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Built-in timing circuit greatly

simplifies and reduces the cost of PC

board design

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Speed trip point adjustable with

external resistor and capacitor

Potential Applications

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Under-speed detection for fans

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Conveyors

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Motor control

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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.