Allegro MicroSystems has announced a new linear Hall-effect sensor IC - the A1357 - with an ambient temperature range of 40°C - 150°C. It is a high precision, customer programmable, Hall-effect linear IC with a pulse width modulated (PWM), current sourced (2-wire) output.
The duty cycle (DC) of the PWM output signal (freq: 1 kHz) is proportional to an applied magnetic field. The device converts an analog signal from its internal Hall sensor element to a digitally encoded PWM output signal. The coupled noise immunity of the digitally encoded PWM output is much superior to the noise immunity of an analog output signal.
The BiCMOS, monolithic circuit inside of the A1357 integrates a Hall element, precision temperature-compensating circuitry to reduce the intrinsic sensitivity and offset drift of the Hall element, a small-signal high-gain amplifier, proprietary dynamic offset cancellation circuits, and PWM conversion circuitry. The dynamic offset cancellation circuits reduce the residual offset voltage of the Hall element.
Hall element offset is normally caused by device over molding, temperature dependencies, and thermal stress. The high-frequency offset cancellation (chopping) clock allows for a greater sampling rate, which increases the accuracy of the output signal and results in faster signal processing capability.
The Allegro A1357 sensor IC is targeted at the automotive and industrial markets and is provided in a lead (Pb) free, 3-pin, single inline package (KB suffix), with 100% matte tin leadframe plating. It is priced at $1.50 in quantities of 1,000.