3195

PROTECTED, HIGH-TEMP.,

ACTIVE PULL-DOWN

HALL-EFFECT LATCH

OPERATION

In operation, the output transistor is OFF

until the strength of the magnetic field

perpendicular to the surface of the chip

output transistor switches ON (a logic low)

and is capable of sinking 35 mA of current.

The output transistor switches OFF (a

logic high) when magnetic field reversal

results in a magnetic flux density below the

transfer characteristics graph. Note that the

device latches; that is, a south pole of

sufficient strength will turn the device ON.

Removal of the south pole will leave the

device ON. The presence of a north pole of

sufficient strength is required to turn the

device OFF.

The switch points increase in sensitivity

with increasing temperature to compensate

for the typical ferrite magnet temperature

characteristic. The simplest form of magnet

that will operate these devices is a ring

magnet. Other methods of operation are

possible.

TEST CIRCUIT AND

TYPICAL APPLICATION

An external 0.1

µF to 0.47 µF capacitor, with good high-frequency

characteristics, should be connected between terminals 1 and 2 to

bypass high-voltage noise and reduce EMI susceptibility.

Internal Pull-Down Resistor. An internal pull-down resistor

(nominal 15 k

Ω) is provided to allow testing of the device without the

need for an external load.

3.8 V TO 26 V

WITH TRANSIENTS

Dwg. EH-007

L

R

TO

µP

L

C

3

X

BYPASS

C

2

1

025

50

75

100

20

10

AMBIENT TEMPERATURE IN

°C

18

14

-50

Dwg. GH-060

150

-25

125

16

12