High Sensitivity Low Power TMR Switch
Position Sensing > LF11115TMR
TMR Bipolar Switch 17 Gauss 200nA Push Pull Sensor
Description
The LF11115TMR TMR Switch is a digital bipolar magnetic switch that integrates
TMR and CMOS technology in order to provide a magnetically triggered digital
switch with high sensitivity, high speed, and low power consumption.
It contains a TMR magnetic sensor and CMOS signal processing circuitry within
the same package, including an on-chip TMR voltage generator for precise
magnetic sensing, a TMR voltage amplifier and comparator plus a Schmitt
trigger to provide switching hysteresis for noise rejection, CMOS push-pull
output and X axis sensing direction.
An internal band gap regulator is used to provide a temperature compensated
supply voltage for internal circuits, permitting a wide range of supply voltages.
It draws only 200nA (see Features below) resulting in low power operation,
additionally it has fast response, accurate switching points, excellent thermal
stability, and immunity to stray field interference. It is available in the SOT23-3
package. The output of the LF11115TMR switches low (turns on) when the
magnetic field parallel to the sensing axis exceeds the operate point threshold,
BOP. When the magnetic field is reduced below the release point BRP device
output switches high (turns off). The difference between the BOP and the BRP is
the hysteresis BH of the device.
Functional Block Diagram
Vcc
Power regulator
with temperature
compensation
Offset
TMR
Sensor
Features
Vout
Latch
cancellation
• X axis sensing direction
• Tunneling Magnetoresistance (TMR)
technology
• Ultra low power consumption at
200nA
• High frequency up to 50Hz
• Operation with north and south pole
• 1.8V to 5.5V operating range
GND
Benefits
• Low switching points for high
sensitivity
TMR Switch Typical Applications Circuit
• Wider airgap capability
• Operates with smaller magnets for
cost reduction
• Excellent thermal stability
• High tolerance to external magnetic
field interference
• RoHS compliant
Vcc
Vcc
Out
TMR
0.1µF
Applications
Out
• Proximity detection
• Utility meters including gas and
water meters
• Speed sensing
• Battery powered applications
• Rotary sensing
GND
Output Behavior Versus Magnetic Pole
GND
Parameter
Test Conditions
Output (volts)
Note: It is strongly recommended that an external bypass capacitor be connected in-close-
proximity to the device between the supply and ground pins to reduce noise. The recommended
value for the external bypass capacitor is 0.1μF.
South Pole
North Pole
B > BOPS
Low (On)
High (Off)
0 < B < BRPS
Note:
The output is “High” when power is turned on under zero magnetic field.
When a S Pole approaches the pin 1 side, Vout will transition to Low.
When a N Pole approaches the pin 1 side, Vout will transition to High
© 2020 Littelfuse
Revised: 02/20/20
littelfuse.com
Specifications are subject to change without notice.