High Sensitivity Low Power TMR Switch Position Sensing > LF32115TMR TMR Unipolar Switch 17 Gauss 200nA Open Drain Sensor Description The LF32115TMR TMR Switch is a digital unipolar 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 open drain 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 Functional Block Diagram stability, and immunity to stray field interference. It is available in the SOT23-3 Osc and package. The output of the LF32115TMR switches low (turns on) when the Vcc Duty Control Logic magnetic field parallel to the sensing axis exceeds the operate point threshold, Power regulator with temperature B . When the magnetic field is reduced below the release point B device compensation OP RP output switches high (turns off). The difference between the B and the B is OP RP Vout the hysteresis B of the device. H Offset TMR Driver cancellation Sensor Features GND Tunneling Magnetoresistance (TMR) High frequency up to 50Hz technology GND Operation with north or south pole Low power consumption at 200nA 1.8V to 5.5V operating range X axis sensing direction TMR Switch Typical Applications Circuit Benefits Low switching points for high Wider airgap capability sensitivity Operates with smaller magnets for Vcc Excellent thermal stability 1K cost reduction High tolerance to external magnetic RoHS compliant Vcc TMR Out field interference 0.1F Out Applications GND Proximity detection Speed sensing Utility meters including gas and Battery powered applications water meters Rotary sensing GND Output Behavior Versus Magnetic Pole 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 0.1F. Parameter Test Conditions Output (volts) B > B Low (On) OPS South Pole 0 < B < B High (Off) RPS Note: 1. When power is turned on under zero magnetic field, the output is High. 2. The power-on settling time of the device is 3ms, and the output latches to high level after this settling time. When a S-pole approaches the pin 1 side, Vout will transition to Low. The correct state will be obtained after first excursion of the magnetic field beyond BOP or BRP. 3. The device circuitry is activated for a short period of time as awake state, and deactivated the remainder of the period as sleep state. The device in sleep state will retain the output status of the last sampled state. 2020 Littelfuse Revised: 01/10/20 littelfuse.com Specifications are subject to change without notice.High Sensitivity Low Power TMR Switch Position Sensing > LF32115TMR Absolute Maximum Ratings ( TA = +25C, unless otherwise specified) Symbol Characteristics Values Unit V Supply Voltage 7.0 V CC V Reverse Supply Voltage 0.3 V RCC I Output Current 20 mA OUTSINK B Magnetic Flux Density 4000 Gauss V ESD level(HBM) 4 kV ESD T Operating Temperature -40 ~ 125 C A T Storage Temperature -50 ~ 150 C stg Note: Stresses greater than the Absolute Maximum Ratings specified above may cause permanent damage to the device. These are stress ratings only functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. Electrical Characteristics ( TA = +25C, Vcc = 3.0V) Symbol Characteristics Min. Typ. Max. Unit Conditions V Supply Voltage 1.8 3 5.5 V Operating CC V Output Stress Voltage 5.5 V stress Output = High,V = 3V, cc I (average) Output leak current 1 A leak V = 3V out V OH Output High Voltage Vcc -0.2 V Pull-up Resistance = 1Kohm R off Output turn-off Resistance 10 M Output = High R on Output turn-on Resistance 10 Output = Low Output = Low, V = 3V, cc V OL Output Low Voltage 0.1 V I = 3mA sink I Supply Current 200 nA Output Open CC Freq Response Frequency 50 Hz Magnetic Characteristics ( TA = +25C, Vcc = 3.0V) Symbol Characteristics Min. Typ. Max. Unit B Operation Point 9 17 25 Gauss OP B RP Release Point 5 13 20 Gauss B Hysteresis -- 4 -- Gauss H 2020 Littelfuse Revised: 01/10/20 littelfuse.com Specifications are subject to change without notice.