An ultra-low noise current source for magnetoresistive biosensors biasing

This paper presents an ultra-low noise current source for magnetoresistive biosensors biasing. In biological applications signals can have very low amplitudes, therefore the noise of the biosensor biasing circuit can have a high impact on the measurement resolution. We present an ultra-low noise current source architecture that biases a magnetoresistive biosensor array with negligible noise penalization without using external noise filtering capacitors, allowing the integration of magnetoresistive sensors on CMOS without decreasing the measurement resolution. The circuit was designed and fabricated using AMS 0.35 μm 3.3 V technology.