中图分类号： TN432 文献标识码： A DOI：10.16157/j.issn.0258-7998.200825 中文引用格式： 张孟文，金玉丰. 用于甚低频无线通信的一种低噪声放大器设计[J].电子技术应用，2021，47(1)：46-51，56. 英文引用格式： Zhang Mengwen，Jin Yufeng. Design of a LNA for ULF wireless communication[J]. Application of Electronic Technique，2021，47(1)：46-51，56.
Design of a LNA for ULF wireless communication
Zhang Mengwen1，2，Jin Yufeng1
1.Peking University Shenzhen Graduate School，Shenzhen 518055，China；2.Goodix Technology Co.，Shenzhen 518045，China
Abstract： This paper introduces the design of low noise amplifier, using for ultra-low frequency. There′s a new loop in the paper, formed by a low-pass transconductance and a self-cascode MOSFET, proposed to stabilize the output bias voltage of the amplifier. By using the loop with the constant transconductance bias circuit, the open-loop gain of the amplifier is constant at about 40 dB. It does not vary with the supply voltage, process and temperature. In the amplifier, a self-cascode MOSFET is used as a gain unit to enable the amplifier output range to reach rail to rail, with the use of full differential current bias. This amplifier has a remarkable in-band high-power supply rejection ratio, up to 101.4 dB. The power ripple has almost no effect on the output signal, when the wearable devices are powered by high impedance sources.
Key words : ultra low frequency；low noise amplifier；high power supply rejection ratio；constant open loop gain；output rail to rail