## 1 Introduction  
Sensor Interfaces are key elements in industrial applications as they provide dedicated power levels for various actuators, sensors, and read-back links within the system. To ensure reliable circuit operations, power management systems require control levels configuration for their data communication channels in terms of human safety and circuitry protection [1, 2]. One main requirement to afford optimum performance is to have an isolation system that enables digital signal transmission while eliminating dangerous effects on low-voltage system electronics caused by the high-voltage domain. Typically, in high-voltage applications, isolation barrier breakdown can not only cause potential hazards to end users but also may cause damage to low-voltage control circuits affecting the system functionality. For example, if the isolation barrier failure mode occurs in the AC motor drive system, either the damage is limited to the die with the isolation capacitor or to the gate driver die [3]. Digital isolation techniques are in the broad area of data communication systems for modern sensor interfaces. They are widely used in different applications, including medical equipment, network interfaces, and automotive industrial systems. The purpose of the isolation barrier is to eliminate voltage spikes and unwanted ground loops that may exist between high-voltage and low-voltage circuit domains [4]. This is achieved by establishing two separate ground references for the transmitter (Tx) and receiver (Rx) circuits, allowing safe communication between different voltage levels. Additionally, it is mandatory in many industrial applications to maintain the required protection level against multiple noise sources, such as lightning strikes, while ensuring the correct functionality at the targeted signal transfer speed. The coupling methods to perform the digital isolation are based mainly on three types: optocouplers, capacitors, and transformers. Digital isolators based on optocouplers were the very first conventional way in data communication systems that exploit light to transfer data in the near-infrared band. The main advantages of optocouplers are a high isolation breakdown and immunity to electromagnetic interference (EMI). On the other hand, they suffer from high power consumption (30 mA at 40 Mbps) [5], which causes lifetime degradation. Moreover, optocouplers are not compatible with the CMOS process since they are fabricated in gallium arsenide (GaAs), and discrete chips are required for multiple isolation channels [6; 7]. Capacitive isolators are implemented in silicon dioxide (SiO\({}_{2}\)) technology which has a dielectric strength of up to 500 V/\(\upmu\)m [8; 9]. As a result, an isolation voltage of 1.5 kV\({}_{\text{rms}}\) can be achieved within a 3 \(\upmu\)m SiO\({}_{2}\) thickness between metal-1 and metal-6 in a 0.18 \(\upmu\)m CMOS process [10]. Compared to optocouplers, capacitive isolators can be integrated with the CMOS process and have lower power consumption [11; 12; 13]. In addition, capacitive techniques are well-suited for high-speed data transfer due to their higher EMI. However, because of the fast ground shift (in hundreds of kV/\(\upmu\)s) between the two circuit domains, capacitive techniques have lower common mode transient immunity (CMTI) [14; 15; 16]. This common mode current, which is proportional to the capacitor size, may corrupt data transfer and increase the bit error rate (BER). To achieve higher data rates, more isolation voltage, and improve the CMTI, the inductive-based isolation method is adopted. Inductive methods use polyimide, with a field strength of 250 V/\(\upmu\)m before breakdown, as the insulation material between coils to transfer data and power through magnetic coupling. Polyimide outperforms SiO\({}_{2}\) by having a lower parasitic capacitance of the isolation barrier at the expense of added fabrication cost [17; 18; 19; 20; 21; 22; 23; 24].