Hall-effect sensor ICs for automotive applications

May 08, 2013 // By Graham Prophet
Factory-programmable, linear 3.3 V devices provide low-noise temperature-stable analog output for high-bandwidth applications.

Two factory one-time programmable linear Hall-effect sensor ICs which eliminate the need for customers to optimise or program the devices for their finished sensor assemblies are now available from Allegro MicroSystems Europe. The A1318 and A1319 each provide a low-noise temperature-stable output, and are targeted at high-bandwidth displacement and angular position sensing applications involving a 3.3-V supply rail. Although the device architecture supports magnetic input sensitivity ranges of 1.32 to 2.64 mV/G and 2.64 to 5.94 mV/G, respectively, the products initially being released to market are factory programmed to specific magnetic input sensitivity levels.

The first device types released are the A1318LLHLX-1-T (1.35 mV/G sensitivity), the A1318LLHLX-2-T (2.5 mV/G sensitivity) and the A1319LLHLX-5-T (5.0 mV/G sensitivity). The A1318 and A1319 are ratiometric Hall-effect sensor ICs which provide a voltage output that is proportional to the applied magnetic field. The quiescent voltage output is adjusted around 50% of the supply voltage. The accuracy of the A1318/19 is enhanced via end-of-line optimisation. Each device features non-volatile memory to optimise device sensitivity and the quiescent voltage output for a given application or circuit.

The temperature coefficients for both sensitivity and the quiescent voltage output are programmed over temperature at Allegro to maximise accuracy and minimise distribution tolerances. The A1318 and A1319 provide low output noise (13 mV p-p at 5.0 mV/G sensitivity for the A1319) and low EMI susceptibility at various frequencies. They also support a fast refresh rate of 20 kHz for high bandwidth applications.

Both devices also support undervoltage lockout protection and output voltage clamps to provide short-circuit diagnostic capabilities. The A1318 and A1319 are targeted at the automotive, industrial and consumer markets, and are currently being offered in a small LH (SOT-23W) surface mount package.

Allegro, www.allegromicro.com/en/Products/Magnetic-Linear-And-Angular-Position-Sensor-ICs/Linear-Position-Sensor-ICs/A1318-9.aspx