A1205: Continuous-Time Bipolar Switch

The Allegro A1205 Hall-effect bipolar switch is a next-generation replacement and extension of the popular Allegro A3134 bipolar switch. The A1205 has identical specifications as the A1201 but is recommended for applications that require pulsing VCC to conserve power. For standard applications, where VCC is constant, please refer to the A1201 through A1204 devices.

Overall, the A120x family, produced with BiCMOS technology, consists of continuous-time devices that feature fast power-on time and low-noise operation. Device programming is performed after packaging to ensure increased switchpoint accuracy by eliminating offsets that can be induced by package stress. Unique Hall element geometries and low-offset amplifiers help to minimize noise and to reduce the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress.

The A120x Hall-effect bipolar switches include the following on a single silicon chip: voltage regulator, Hall-voltage generator, small-signal amplifier, Schmitt trigger, and NMOS output transistor. The integrated voltage regulator permits operation from 3.8 to 24 V. The extensive on-board protection circuitry makes possible a ±30 V absolute maximum voltage rating for superior protection in automotive and motor commutation applications, without adding external components.

ASIL LogoThe A1205 complies with the international standard for automotive functional safety, ISO 26262, as a Quality Managed (QM) product. The device is classified as a SEooC (Safety Element out of Context) and can be easily integrated into safety-critical systems requiring higher ASIL ratings that incorporate external diagnostics or use measures such as redundancy. Safety documentation will be provided to support and guide the integration process. For further information, contact your local Allegro field applications engineer or sales representative.


Astrorep Inc. (Allegro and Sanken Semiconductors, Sanken Power Supplies)
141 John Street, Suite 300
Babylon, NY 11702
Phone: (631)422-2500
Fax: (631)422-2504
Web: www.astrorepinc.com
Email: donna.tweedy@astrorepinc.com

If this is not your local representative, find your local sales rep here.

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  • AEC-Q100 automotive qualified
  • Quality managed (QM), ISO 26262 compliant
  • Ideal for applications that require pulsing VCC to conserve power
  • Continuous-time operation
  • Fast power-on time
  • Low noise
  • Stable operation over full operating temperature range
  • Reverse battery protection
  • Solid-state reliability
  • Factory-programmed at end-of-line for optimum performance
  • Robust EMC performance
  • High ESD rating
  • Regulator stability without a bypass capacitor

The small geometries of the BiCMOS process allow these devices to be provided in ultrasmall packages. The package styles available provide magnetically optimized solutions for most applications. Package LH is a SOT23W miniature thin-profile surface-mount package, while package UA is a three-lead ultramini SIP for throughhole mounting.


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Product Image Functional Block Diagram

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check
Distributor Stock
A1205LLHLT-T 3-lead SOT -40°C to 150°C Yes View Data Contact your
local sales rep
Check Stock
A1205LLHLX-T 3-lead SOT -40°C to 150°C Yes View Data Contact your
local sales rep
Check Stock
A1205LUA-T 3-lead SIP -40°C to 150°C Yes View Data Contact your
local sales rep
Check 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.

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