| Resumen |
In this paper we present the design of a low noise second order ?? modulator with 3V power supply, rail to rail, 40KHz signals with an oversampling ratio of 128 dedicated to convert analog to digital signal of a Hall Effect sensor. The signal to noise ratio is theoretical estimated over 90dB over for a 0.5µm CMOS technology with 1800µW of power consumption. The conventional stability criteria are implemented and the operational Transconductance Amplifier (OTA) integrator was designed in two stages with Miller compensation. In general the design ?? modulator requires a signal condition between 100mV and 500mV. The Hall Effect sensor is based on a MEMS micromachining of SOI-wafers technology, the sensitivity is about (?100V/AT), i.e., for an input dc-current of 189?A the sensor has a sensitivity of 103.3mV/mA-Gauss (V/AT) with a magnetic field that was cycled from 2mT to 2.7T. The measured voltage generated from the magnetic field is from -1.5mV to 1.5mV. In fact the Hall-Effect sensor has the possibility to measure a 3 dimension (3D) orthogonal fields. |
