As the precise acquisition of continuous ExG (ENG, ECG, etc.) and biocurrent (chemical, PPG, etc.) signals provides further insights into chronic health conditions [1, 2], a low-power readout system capable of simultaneously recording ExG and biocurrent signals with high precision is beneficial (Fig. 33.11.1(a)). Such a system requires $\mathrm{BW}\gt5 \mathrm{kHz}$, an input range (IR) $\gt100 \mathrm{mV} \mathrm{V}_{\mathrm{PP}}$ is necessary to prevent saturation. Likewise, for biocurrent acquisition, a system has to meet $\mathrm{BW}\gt1 \mathrm{kHz}$, noise floor $\sim 1 \mathrm{pA}_{\mathrm{rms}}/\sqrt{\mathrm{Hz}}$, and $\mathrm{DR}\gt100 \mathrm{dB}$ to detect small charge perturbations without saturation from large baseline currents. Extensive effort has been conducted to design a simultaneous V & I monitoring system (Fig. 33.11.1(b)). For instance, [1] allows the design of a simultaneous V & I monitoring system based on simple integration of individual readout schemes. However, this system consumes power $\gt100 \mu \mathrm{W}$ and is unsuitable for simultaneous ExG and biocurrent signals due to the limited BW. Although [2] achieves wide BW for both signals, it cannot record V & I simultaneously due to the time-division manner and also has narrow IRs. On the other hand, [3] employing frequency division, achieves simultaneous readout while consuming low power. However, it is vulnerable to artifacts, while the BW of each V & I readout limits the other. This paper presents a simultaneous V & I recording system using a single 2 nd -order continuous-time $\Delta \Sigma$ modulator (CT-DSM). Such simultaneous recording is achieved by using a highly linear hybrid G m C integrator with a triplet VCO-based quantizer, where the differential voltage and single-ended current are combined into differential and common mode signals (Fig. 33.11.1 (c)).