US5781LUA Melexis Inc, US5781LUA Datasheet - Page 7

• Manufacturer Part Number: US5781LUA
• Description: IC HALL EFFECT SWITCH TO-92UA
• Manufacturer: Melexis Inc
• Type: Unipolar Switchr

Specifications of US5781LUA

• Sensing Range: 15mT Trip, 3.5mT Release
• Voltage - Supply: 3.5 V ~ 24 V
• Current - Supply: 5mA
• Current - Output (max): 50mA
• Output Type: Digital, Open Drain
• Operating Temperature: -40°C ~ 150°C
• Package / Case: TO-92UA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

An invisible or sealed switch may be made with either configuration. The Hall IC may be inside a sealed
container to shield it from oil or water, while the magnetic field penetrates or “sees” through the sealed
enclosure. Refer to Figure 4.
Figure 4, Sealed Box
The Hall IC can be shielded from
the elements and remain
sensitive to magnetic fields.
S
N
A-07
Interrupt Switch
When the Hall IC and magnet are fixed, the Hall IC can be activated using a ferrous vane. This system,
composed of a Hall IC, magnet and ferrous vane is called an interrupt switch. In the interrupt switch the
magnet is positioned so the South pole turns ON the switch while the Hall IC and magnet positions are
fixed relative to each other. When a vane made of a ferrous material is placed between the magnet and
Hall IC, the magnetic field is shunted or reduced to a very small fraction of the maximum field, turning
the switch OFF. This vane is shown in Figure 5 as a notched interrupter. This switch is an effective way
to sense position.
Figure 5, Interrupt Switch
In Figure 5A, the South magnetic pole is exposed to the Hall IC through the vane, so the switch turns
ON. In figure 5B, the switch turns OFF because the magnetic field is blocked by ferrous material.
Figure 5B
Figure 5A
S
S
N
N
A-08
A-09
Section 3 - Applications
3-5