Product category:
Analogue and Mixed Signal ICs
News Release from: Allegro MicroSystems Europe | Subject: A3212
Edited by the Electronicstalk Editorial
Team on 01 April 2004
Hall-effect switch is a sensitive sort
A novel micropower omnipolar Hall-effect switch combines ultrasensitive, pole-independent switching with a latched digital output.
A novel micropower omnipolar Hall-effect switch combines ultrasensitive, pole-independent switching with a latched digital output The new A3212 provides improved magnetic sensitivity with minimal shifts in switch point with temperature, and its small package size and low power requirement make it a cost-effective contactless replacement for mechanical or reed switches in all types of portable applications
This article was originally published on Electronicstalk on 15 Dec 2005 at 8.00am (UK)
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A 2.5-3.5V battery requirement and a unique clocking scheme reduce the average operating power requirements to less than 15uW from a 2.75V supply.
Unlike other Hall-effect switches, the A3212 offers true omnipolar operation, so that either a north or south pole of sufficient strength will turn the output on; in the absence of a magnetic field, the output is off.
This polarity independence, coupled with the minimal power requirement, allows the device to easily replace reed switches for superior reliability and ease of manufacturing, while eliminating the requirement for signal conditioning.
Improved stability is made possible through chopper stabilisation (dynamic offset cancellation), which reduces the residual offset voltage normally caused by device overmoulding, temperature dependencies, and thermal stress.
The sensor is ideally suited for operation in battery-operated, handheld equipment, or any portable or battery operated device requiring a contactless switch such as flip phones, pagers, personal organisers, laptops and palmtops.
The A3212 is supplied in an ultraminiature single-inline package measuring only 0.75 x 2 x 3mm for through-hole or surface mounting, or a 3-lead miniature low-profile surface-mount (SOT23W) package.
Standard operating range is from -40 to +85C, but a version is available for operation over the extended temperature range from -40 to +150C.
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