Presented is a low noise interface circuit that is tuned to the needs of self-assembly monolayers biosensor SoC. The correlated double sampling(CDS) unit of the readout circuit can reduce 1/f noise, KTC noise and fixed noise of micro arrays effectively. The circuit is simulated in a 0.6 μm/level 7 standard CMOS process, and the simulated results show the output voltage has a good linearity with the transducing current of the micro arrays. This is a novel circuit including four amplifiers sharing a common half-circuit and the noise reducing CDS unit. It could be widely used for micro array biosensors.
According to the characteristics of neural signal,a low-voltage and high-speed operational transconductance amplifier has been realized as a direct readout circuit. To reduce the size and cost of this chip, the amplifier uses feedforward compensation technique without Miller capacitor. Using capacitors as a closed-loop feedback not only amplifies the neural signal, but also reduces chip power consumption by replacing the feedback resistor. Simulations were carried out with 0.18m CMOS technology, and the simulation results satisfied the requirements of neural signal.
PAN Yinsong ZHANG Chengwei LIU Fenglin YANG Shuaiju
