HALL EFFECT

GEAR-TOOTH SENSORS

–ZERO SPEED

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

All devices, when used with a back-

biasing magnet, can be configured to turn ON

or OFF with the leading or trailing edge of a

gear tooth or slot. Changes in fields on the

magnet face caused by a moving ferrous

mass are sensed by two integrated Hall

transducers and are differentially amplified by

on-chip electronics. The on-chip temperature

compensation and Schmitt trigger circuitry

minimizes shifts in effective working air gaps

and switch points over temperature making

these devices ideal for use in ignition timing,

anti-lock braking systems, and speed mea-

surement systems in hostile automotive and

industrial environments.

Each Hall effect digital Integrated circuit

includes two quadratic Hall effect sensing

elements, a voltage regulator, temperature

compensating circuitry, low-level amplifier,

Schmitt trigger, and an open-collector output

driver. The on-board regulator permits

operation with supply voltages of 4.5 to 24

volts. The output stage can switch up to 20

mA at conservatively specified repetition

rates to 20 kHz and is compatible with bipolar

and MOS logic circuits.

FUNCTIONAL BLOCK DIAGRAM

Both magnetic characteristics are available in a choice of two operat-

ing temperature ranges. Suffix EU devices have an operating range of

-40

°C to +85°C while suffix LU devices feature an operating range of

-40

°C to +150°C. All devices are packaged in a 3-pin plastic SIP.

Limits

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Supply Voltage

Operating

4.5

—

24

V

Power-Up State

—

3058* only,

Output is OFF

—

Output Saturation Voltage

—

135

400

mV

Output Leakage Current

—

—

5.0

µA

Supply Current

—

7.2

14

mA

Output Rise time

—

100

—

ns

Output Fall time

—

100

—

ns

OUTPUT

X

X

Dwg. FH-010

SUPPLY

GROUND

REG

+

–

1

2

3

Copyright © 1989, 1995 Allegro MicroSystems, Inc.