An integrated front-end vertical hall magnetic sensor fabricated in 0.18 μm low-voltage CMOS technology

Abstract

An integrated front-end vertical CMOS Hall magnetic sensor is proposed for the in-plane magnetic field measurement. To improve the magnetic sensitivity and to obtain low offset, a fully symmetric vertical Hall device (FSVHD) has been optimized with a minimum size design. A new four-phase spinning current modulation associated with a correlated double sampling (CDS) demodulation technique has been further applied to compensate for the offset and also to provide a linear Hall output voltage. The vertical Hall sensor chip has been manufactured in a 0.18 μm low-voltage CMOS technology and it occupies an area of 1.54 mm2. The experimental results show in the magnetic field range from –200 to 200 mT, the entire vertical Hall sensor performs with the linearity of 99.9% and the system magnetic sensitivity of 1.22 V/T and the residual offset of 60 μT. Meanwhile, it consumes 4.5 mW at a 3.3 V supply voltage. The proposed vertical Hall sensor is very suitable for the low-cost system-on-chip (SOC) implementation of 2D or 3D magnetic microsystems.