A 146-dB-Ohm Gain 14-pARMS Noise Patch-Clamp Amplifier for Whole-Cell Ion Current Detection

Abstract

The membrane clamp technique is an important tool to reflect the electrophysiological characteristics of cells by recording the ionic currents of cellular channels. Embedded systems work in systems designed for specific user groups and are used to implement specific functions. The membrane clamp amplifier built with embedded technology has the advantages of miniaturization, specialization, low power consumption, high integration, high resource utilization, and a long life cycle, which can avoid the inconvenience to developers and experimenters due to the update of general-purpose computer software and hardware. In this paper, a patch-clamp amplifier (PCA) based on a transimpedance amplifier (TIA) is proposed, which includes a glass microelectrode series resistance/capacitance compensation circuit and feedback resistor parasitic capacitance compensation. The prototype is designed using 180 nm CMOS technology and occupies an area of $720\mu \text{m}\times 630\mu \text{m}$ . The prototype achieves a transimpedance gain of 145.6 dB-Ohm, a -3 dB bandwidth greater than 15 kHz, and an input reference noise current of 13.98 pARMS. Experimental results show that the proposed PCA is capable of compensating up to 30 pF of electrode capacitance and up to 10 MΩ for 86% of the series resistance, respectively. In addition, when the feedback resistor parasitic capacitance compensation circuit is enabled, the overshoot phenomenon disappears, overcoming the shortcomings of the conventional diaphragm clamp amplifier current clamp and maintaining the original key performance.