Single-photon avalanche diodes (SPADs), featuring ultra-high sensitivity and fast response speed, are widely used in underwater wireless optical communications (UWOC). Since the attenuation coefficient of red light is smaller than that of blue-green light in highly turbid waters, therefore, a red-enhanced SPAD based on 250 nm BCD process was specially designed to improve its photon detection efficiency (PDE) in red light band, and then a SPAD-based UWOC simulation system for turbid waters channel was developed in this work. The UWOC simulation results with custom-designed SPAD show that the transmission distance is up to 75 m for a data rate of 1 Mbps at a BER of 3.8×10⁻³, and the effective communication distance was improved by at least 15% compared with the UWOC system with blue-green SPADs. This indicated that our-designed SPAD can effectively improve the communication performance of UWOC in turbid waters. Besides, the impact of SPAD’s working conditions such as excess bias voltage, operating temperature and dead time, on BER was analyzed as well.

A 64 Gb/s PAM-4 micro-ring modulation driver is fabricated in a 28 nm CMOS process. The design employs a digital based segmented DAC architecture to achieve high linearity. A nonlinear equalization circuit is implemented to compensate for both the dynamic and static nonlinearities inherent in the electro-optic conversion process. To improve energy efficiency, the number of digital slices is reduced through an optimized weighting scheme. Furthermore, signal bandwidth and integrity are enhanced by optimizing the clock distribution network and the 4:1 multiplexer structure. Enabled by the nonlinear compensation technique, the prototype delivers a clearly opened 64 Gb/s PAM-4 optical eye diagram.

Cone shaped micro-bumps with Cu are successfully demonstrated with nanoparticle deposition process, which is previously used to deposit Au cone shaped bumps. The process employs helium gas to carry nanoparticles and sprays the nanoparticles onto patterned resist on target wafer. Then cone shaped bumps can be formed with self-forming by flow of the carrier gas. The paper presents formation process and basic characteristics of the bumps. The first integration result including electrical and mechanical characteristics are also presented.

Test access mechanism (TAM) design is crucial for test efficiency in 2.5D/3D integrated circuits. This paper proposes a flexible and reconfigurable scan chain generation method to optimize TAM resources in 2.5D/3D integrated circuits. The method innovatively introduces a grid-based power-aware test architecture that enables dynamic scan chain reconfiguration, allowing cores to be flexibly allocated into different scan chains for optimal test scheduling. A mathematical model is developed to optimize scan chain configurations and their test schedules. Experimental results on the ITC’02 benchmark circuits demonstrate that the proposed method achieves up to 27.1% reduction in test time and up to 37.39% improvement in TAM utilization compared with the existing robust optimization approach. Moreover, it provides a more flexible and scalable test architecture for 2.5D/3D ICs.

This paper presents an always-on wake-up detector for random sparse event (RSE) monitoring in IoT sensor nodes. The proposed design implements zero-mean normalized cross-correlation (ZNCC) in the analog current domain, providing high robustness to input DC offset and amplitude scaling. A reconfigurable mean-generation circuit enables efficient sliding-window mean removal, reducing the effect of DC offset variations. A normalization-equivalent decision architecture achieves amplitude-scaling invariance without explicit division or square-root operations, thereby reducing circuit complexity. Furthermore, a two-step wake-up scheme improves system energy efficiency via progressive resource activation. Implemented in a 180-nm CMOS process, the detector demonstrates reliable wake-up detection for a representative keyword-envelope signal, with an average power consumption of 865 nW at 1 V. The ZNCC-equivalent metric exhibits low variation under 100–900 mV DC offset and 0.5×–5× amplitude scaling, indicating strong robustness to signal fluctuations.

Permanent Magnet Synchronous Motor (PMSM) is a strongly coupled nonlinear system. Conventional vector control suffers from large speed overshoot and poor anti-disturbance performance. Based on the PMSM mathematical model, this study compares common sliding mode controllers (SMC), designs a novel sliding mode controller by improving the exponential reaching law (NSMC) with a Linear Extended State Observer (LESO) and verifies its stability via mathematical derivation and experiments. The proposed controller features smaller overshoot, faster speed response and stronger disturbance rejection for PMSM than the conventional one, which validates the conclusion.

This paper presents a capacitor-less NMOS low-dropout regulator (LDO) implemented in a 0.18 μm BCD process for wireless sensor network applications. Featuring simple structure and easy integration, the proposed LDO achieves a maximum dropout voltage of merely 46 mV with quiescent current below 4.2 μA. It attains a peak current efficiency of 99.8% under full-load conditions. When the load current switches rapidly between 0 A and 200 mA, the maximum undershoot and overshoot voltages are 95.34 mV and 24.93 mV, respectively, demonstrating excellent transient response performance. The proposed LDO integrates over-temperature protection, over-current protection, soft-start, under-voltage lockout, and automatic discharge circuits to ensure reliable operation under abnormal conditions.

A self-tuning wireless power transfer (WPT) system for dual receivers with different resonant frequencies is presented. The proposed system employs an LCC-S compensation topology, a long-elliptical transmitting coil, and primary-side phase detection for operating-frequency adjustment without requiring receiver-side feedback information. Two receivers with resonant frequencies of 110 kHz and 120 kHz are used to verify the proposed approach under single- and dual-receiver conditions. Experimental results show that one of the preset operating frequencies, 110 kHz, 115 kHz, or 120 kHz, is automatically selected according to the receiver configuration. Continuous output during receiver transitions, output power close to 15 W per active receiver, and a maximum overall efficiency of 80.1% are also confirmed. The feasibility of the proposed self-tuning method for wireless power delivery to multiple heterogeneous receivers is thus verified.

This work proposes two novel compact coaxial diplexer designs based on inline mixed-coupled filters, namely diplexer I and diplexer II. To fulfill external quality factor (Q_e) can be relatively independently tuned for each channel, the inductive coupling windows at the common port were introduced for both diplexers. The structure is straightforward, which mitigate common-port sensitivity effectively. Based upon this architecture, diplexer I utilizes deformed square coaxial resonators (DSCRs) to implement a third-order mixed-coupled filtering response for each channel. Due to the inherently advantages of mixed-coupling techniques, four controllable transmission zeros (TZs) were generated within a simplified inline topology, thereby achieving a high isolation of over 47 dB. To achieve further miniaturization, diplexer II integrated a dual-mode metal plate coupled resonator (DM-MPCR) with a single-mode DSCR to obtain three-order responses within each individual channel. To the authors’ best knowledge, this is the first time that attempt to combine a dual-mode resonator with mixed-coupling techniques to implement a coaxial diplexer design, achieving compact sizes of 0.67 λ × 0.16 λ × 0.18 λ while maintaining an isolation greater than 34 dB. To experimental validation, both prototypes were successfully fabricated using commercial 3-D metal printing technology. The measured results showed good agreement with the simulations, which demonstrate the potential advantages of mixed-coupling techniques for realizing high-performance and miniaturized coaxial diplexers.