US5781LUA Melexis Inc, US5781LUA Datasheet - Page 33

• 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: -

Flow Meter
One popular device that uses a Hall IC is a flow meter (Figure 15). The spoked wheel (paddle wheel), is
driven by some type of medium flowing through the pipe. A magnet is attached at the tip of each spoke.
In the presence of moving vapor or liquid, the magnets spin at a speed related to the viscosity of the medi-
um flowing through the device. The spinning magnets will switch the Hall IC, producing a square wave
output, with a frequency proportional to the flow rate.
Figure 19, Flow Meter
N
S
Liquid or vapor entering in the
direction of the arrow spins the
paddle wheel switching the Hall
IC “ON” and “OFF”, creating a
square wave output
.
Power Control
Many switches must control significant power. A Hall IC can do this only through a relay or Power FET.
For a component cost of $1.00, an isolated 50 Volt, 50 Amp switch can be made.
Figure 20, Power Switch
12V
Load
U18
627
Section 3 - Applications
3-19