The performance requirement of an operational trans-conductance amplifier (OTA) for the high gain and low power neural recording frontend has been addressed in this paper. A novel split differential pair technique is proposed to improve the gain of the OTA without any additional bias current requirements. The design demonstrates a significant performance enhancement when compared to existing techniques, such as gain-boosting and recycling. A qualitative and quantitative treatment is presented to explore the impact of the split ratio on the performance parameters of gain, bandwidth, and linearity. A prototype implemented in TSMC 65 nm CMOS technology achieved 68 dB open loop-gain (13 dB higher than the conventional circuit) and a 17 kHz 3-dB bandwidth. A linearity of − 62 dB has been achieved with 7 mV pk–pk signal at the input. The circuit operates from a 1 V supply and draws 0.6 uA static current. The prototype occupies 3300 um2 silicon area.
Nagulapalli, RajasekharHayatleh, KhaledBarker, Steve
Zourob, SaddamYassine, Nabil
Faculty of Technology, Design and Environment\School of Engineering, Computing and Mathematics
Year of publication: 2018Date of RADAR deposit: 2018-03-16