A3211 and A3212: Micropower, Ultrasensitive Hall-Effect Switches

Description

The A3211 and A3212 integrated circuits are ultrasensitive, pole independent Hall-effect switches with latched digital output. These devices 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 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.

Top Features

  • AEC-Q100 automotive qualified 
  • Micropower operation
  • Operate with north or south pole
  • 2.5 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
  • Simply manufacturable with magnet pole independence

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Compliant
Part Composition /
RoHS Data
Comments Samples Check Stock
A3211EEHLT-T 6-lead MLP -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A3211EELLT-T 3-lead MLP -40°C to 85°C Yes View Data Last time buy Contact your
local sales rep
Check
Distributor Stock
A3211ELHLT-T 3-lead SOT -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3211ELHLX-T 3-lead SOT -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212EEHLX-T 6-lead MLP -40°C to 85°C Yes View Data Discontinued Contact your
local sales rep
Check
Distributor Stock
A3212EELLT-T 3-lead MLP -40°C to 85°C Yes View Data Last time buy Contact your
local sales rep
Check
Distributor Stock
A3212ELHLT-T 3-lead SOT -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212ELHLX-T 3-lead SOT -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212EUA-T 3-lead SIP -40°C to 85°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212LLHLT-T 3-lead SOT -40°C to 150°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212LLHLX-T 3-lead SOT -40°C to 150°C Yes View Data Contact your
local sales rep
Check
Distributor Stock
A3212LUA-T 3-lead SIP -40°C to 150°C Yes View Data Contact your
local sales rep
Check
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.

Packaging

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.

Packages

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