Micropower, High Sensitivity Unipolar Hall Switch

AS168

The AS168 is an ultra-sensitive Hall unipolar switch with digital output, mainly designed for battery-operation, hand-held equipment. Special CMOS process is used for low-voltage and low-power requirement. A chopper stabilized amplifier improves stability of magnetic switch points. The circuit provides an internal control clocking mechanism to cycle power to the Hall sensor and analog signal processing circuits. This serves to place the high current-consuming portions of the circuit into a sleep mode. Periodically the device is awakened by this internal logic and the magnetic flux from the Hall sensor is evaluated against the predefined thresholds. If the flux density is above or below the Bop/Brp thresholds then the output transistor is driven to change states accordingly. While in the sleep cycle the output transistor is latched in its previous state. The design has been optimized for service in applications requiring extended operating lifetime in battery powered systems. The device switching behavior is unipolar, it means the south pole sufficient strength will turn the output on. If the magnetic flux density is larger than operating point(Bop), the output will be turned on; if it is less than releasing point(Brp), the output will be turned off. The AS168 is available in SIP-3L, SOT23-3L packages.

Features

 Micropower Operation

 Operating Voltage Range: 1.5V~5.5V

 Magnetic Sensitivity: Bop=40G, Brp=30G(Typ.)

 Operating Temperature Range: -40°C ~ 85°C

 Stabilized Chopper

 Superior Temperature Stability

 Built-in Push-Pull Output Stage

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