General description

The NMH1000 is a hall effect magnetic field switch. The switch is most sensitive to a

vertical field passing through the top-to-bottom surfaces, orthogonal to the plane of the

application printed circuit board. The switch operates at low voltage, low current, low

output data rate, and is a small physical size.

Processing of input consists of functional blocks such as a configurable state machine,

analog-to-voltage conversion of the input, and comparison to generate the bi-state

output, arranged in linear succession.

Features and benefits

• Threshold selection 3-state hardware pin.

• Threshold selection data bit(s) in an I2C accessible register.

• Sample rate selection 3-state hardware pin.

• Sample rate selection data bit(s) in an I2C accessible register.

• Mode selection hardware pin to select between standalone or I2C serial interface.

• Mode selection data bit(s) in an I2C accessible register.

• Two types of output indicate the absence of a magnetic field as compared to an

internally set threshold:

– Binary state hardware pin.

– Binary state data bit(s), configurable as assert-high or assert-low, in an I2C

accessible register.

Applications

• Electronic system wake-up: Detecting the proximity vs. lack of proximity to an

included magnet when the electronics are removed from its delivery packaging, to

wake up the electronics.

• Laptop lid open / closed: Detecting the proximity vs. lack of proximity to a magnet

mounted to laptop lid, to trigger a status change, for example turn on / off the display.

• Door or window open / closed: Detecting the proximity vs. lack of proximity to a

magnet mounted to a door, lid, or window, to trigger a status change, for example an alarm.