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High-Performance Power ICs and Hall-Effect Sensors
Related Links:
Datasheets:
A3211 and A3212: Micropower, Ultra-Sensitive Hall-Effect Switches (PDF)
Selection Guides:
Hall-Effect Sensors,
Omnipolar Hall-Effect Digital Switches
Technical Publications:
Technical Advances in Hall-Effect Sensing (PDF),
Unipolar Hall-Effect Sensors
FAQs:
Digital Hall-Effect Sensors FAQ,
A3212: Micropower, Ultra-Sensitive Hall-Effect Switch FAQ
Press Releases:
New Micropower Omnipolar Ultra-Sensitive Hall-Effect Switch,
A3212/3/4: Allegro MicroSystems, Inc. Announces New Micropower Omnipolar Digital Hall-Effect Switches
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A3211 and A3212
Micropower, Ultra-Sensitive Hall-Effect Switches
Features
- Micropower Operation
- Operate with North or South Pole
- 2.5 V to 3.5 V Battery Operation
- Chopper Stabilized
Superior Temperature Stability
Extremely Low Switch-Point Drift
Insensitive to Physical Stress - Solid-State Reliability
- Small Size
- Easily Manufacturable with Magnet Pole Independence
Description
The A3211 and A3212 integrated circuits are ultrasensitive, pole independent Hall-effect switches with latched digital output. These sensors are especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palmtop computers. A 2.5 to 3.5 V operation and a unique clocking scheme reduce the average operating power requirements to less than 15 µW with a 2.75 V supply.
Unlike other Hall-effect switches, either a north or south pole of sufficient strength will turn the output on in the A3212, and in the absence of a magnetic field, the output is off. The A3211 provides an inverted output. The polarity independence and minimal power requirements allow these devices 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 stabilization (dynamic offset cancellation), which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress.
This device includes on a single silicon chip a Hall-voltage generator, small-signal amplifier, chopper stabilization, a latch, and a MOSFET output. Advanced CMOS processing is used to take advantage of low-voltage and low-power requirements, component matching, very low input-offset errors, and small component geometries.
Four package styles provide magnetically optimized solutions for most applications. Miniature low-profile surface-mount package types EH and EL (0.75 and 0.50 mm nominal height) are leadless, LH is a 3-pin low-profile SMD, and UA is a three-pin SIP for through-hole mounting. Packages are lead (Pb) free (suffix, –T) with 100% matte tin plated leadframes.
Functional Block Diagram
| Part Number | Package Type | RoHS Compliant |
Part Composition/ RoHS Data |
Temperature | Comments | Samples | Distributor Stock |
|---|---|---|---|---|---|---|---|
| A3211EEHLT-T | 6-lead MLP | Yes | view data | -40 °C to 85 °C | |||
| A3211EELLT-T | 3-lead MLP | Yes | view data | -40 °C to 85 °C | |||
| A3211ELHLT-T | 3-lead SOT | Yes | view data | -40 °C to 85 °C | |||
| A3211EUA-T | 3-pin SIP | Yes | view data | -40 °C to 85 °C | |||
| A3212EEHLT-T | 6-lead MLP | Yes | view data | -40 °C to 85 °C | |||
| A3212EELLT-T | 3-lead MLP | Yes | view data | -40 °C to 85 °C | |||
| A3212ELHLT-T | 3-lead SOT | Yes | view data | -40 °C to 85 °C | |||
| A3212EUA-T | 3-pin SIP | Yes | view data | -40 °C to 85 °C | |||
| A3212LLHLT-T | 3-lead SOT | Yes | view data | -40 °C to 150 °C | Contact Marketing Representative | ||
| A3212LUA-T | 3-pin SIP | Yes | view data | -40 °C to 150 °C |
Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.