Hall-effect, bipolar switch, A1205, Allegro MicroSystems
Hall-effect bipolar switch is optimised for pulsed power
News Release from:
Allegro MicroSystems Europe Ltd
03 May 2007
The new A1205 from Allegro MicroSystems Europe is a general-purpose Hall-effect bipolar switch that is optimised for applications where pulsing the supply line is used to conserve power. The new device is a next-generation replacement of Allegro's popular A3134 bipolar switch but with enhanced performance in a more compact package. The A1205 is designed to switch in response to a north/south alternating magnetic field, typically from a multi-pole ring magnet. The hysteresis characteristics of the device ensure clean switching of the output, even in the presence of external mechanical vibration and electrical noise.
The A1205 is a BiCMOS continuous-time device featuring a very short 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 minimise noise and to reduce the residual offset voltage normally caused by device overmoulding, temperature excursions, and thermal stress.
The device incorporates, on a single silicon chip, a 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.
Extensive on-board protection circuitry, including reverse battery protection and output short-circuit protection, makes possible a ±30 V absolute maximum voltage rating for superior operation in automotive and motor commutation applications, without the need to add external components.
The A1205 is available in two package options: LH (SOT-23W), a miniature thin-profile surface-mount package, and UA, a 3-lead ultraminiature single-inline package for through-hole mounting. Each package is lead (Pb) free, with a 100% matt tin-plated leadframe.