3 research outputs found
A Quiet Digitally Assisted Auto-Zero-Stabilized Voltage Buffer with 0.6pA Input Current and 0.6μV Offset
No full textThe readout of high impedance sensors and sampled voltage references [1]requires amplifiers with both low offset and low input current. Chopper amplifierscan achieve low offset, but the switching of their input chopper gives rise tosignificant input current (40 to 110pA) [2-4]. Auto-zero (AZ) amplifiers requireless input switching, but exhibit more voltage noise. However, ping-pongamplifiers continuously swap two auto-zeroed input stages, leading to moreswitching [5,7]. In this work, an AZ stabilized topology is proposed, in which asingle amplifier is always present in the signal path. Only one input switch isrequired, resulting in an input current of 0.6pA (max), a 66× improvement on thestate-of-the art [4]. Furthermore, a digitally assisted offset-reduction schemereduces its low-frequency (LF) noise to the theoretical √5× limit. It also achievesa state-of-the-art maximum offset of 0.6μV
A Quiet Digitally Assisted Auto-Zero-Stabilized Voltage Buffer with 0.6pA Input Current and 0.6μV Offset
No full textThe readout of high impedance sensors and sampled voltage references [1]requires amplifiers with both low offset and low input current. Chopper amplifierscan achieve low offset, but the switching of their input chopper gives rise tosignificant input current (40 to 110pA) [2-4]. Auto-zero (AZ) amplifiers requireless input switching, but exhibit more voltage noise. However, ping-pongamplifiers continuously swap two auto-zeroed input stages, leading to moreswitching [5,7]. In this work, an AZ stabilized topology is proposed, in which asingle amplifier is always present in the signal path. Only one input switch isrequired, resulting in an input current of 0.6pA (max), a 66× improvement on thestate-of-the art [4]. Furthermore, a digitally assisted offset-reduction schemereduces its low-frequency (LF) noise to the theoretical √5× limit. It also achievesa state-of-the-art maximum offset of 0.6μV.Electronic InstrumentationMicroelectronic
