This paper presents the first sub-10$\mu$W, sub-0.1% total harmonic distortion (THD) sinusoidal current generator (CG) integrated circuit (IC) that is capable of 20kHz output for the bio-impedance (Bio-Z) sensing applications. To benefit from the ultra-low-power nature of near-threshold operation, a 9b pseudo-sine lookup table (LUT) is 3b $\Delta\Sigma$ modulated in the digital domain, thus linearity burden of the digital-to-analog converter (DAC) is avoided and only a 1.29$\mu$W of logic power is consumed, from a 0.5V supply and a 2.56MHz clock frequency. A half-period (HP) reset is introduced in the capacitive DAC, leading to around 30dB reduction of in-band noise by avoiding the sampling of data-dependent glitches and attenuating the kT/C noise and the non-idealities of reset switches (SW).

翻译：本文提出了首款输出频率可达20kHz、功耗低于10μW、总谐波失真（THD）低于0.1%的正弦波电流发生器（CG）集成电路（IC），适用于生物阻抗（Bio-Z）传感应用。为利用近阈值操作的超低功耗特性，在数字域中对9位伪正弦查找表（LUT）进行3位ΔΣ调制，从而避免了数模转换器（DAC）的线性度负担，并在0.5V电源电压和2.56MHz时钟频率下仅消耗1.29μW逻辑功耗。在电容式DAC中引入半周期（HP）复位机制，通过避免采样与数据相关的毛刺并抑制kT/C噪声和复位开关（SW）的非理想特性，使带内噪声降低约30dB。