Performance Analysis of Ring Oscillators and Current-Starved VCO in 45-nm CMOS Technology

This paper presents a relative study among two Ring oscillators architecture (CMOS, NMOS) and current-starved Voltage-controlled oscillator (CS-VCO) on the basis of different parameters like power dissipation ,phase noise etc. All the design has been done in 45- nm CMOS technology node and 2.3 GHz Centre frequency have been taken for the comparison because of their applications in AV Devices and Radio control. An inherent idea of the given performance parameters has been realize by thecomparative study. The comparative data shows that NMOS based Ring oscillator is good option in terms of the phase noise performance. In this study NMOS Ring Oscillator have attain a phase noise -97.94 dBc/Hz at 1 MHz offset frequency from 2.3 GHz center frequency. The related data also shows that CMOS Ring oscillator is the best option in terms of power consumption. In this work CMOS Ring oscillator evacuatea power of 1.73 mW which is quite low. Keywords: Voltage controlled oscillator (VCO), phase noise, power consumption, Complementary metal-oxide-semiconductor (CMOS), Current Starved Voltage-Controlled Oscillator (CS- VCO), Pull up network (PUN), Pull down network (PDN)

Vernier time-to-digital converter with ring oscillators for in-pixel time-of-arrival and time-over-threshold measurement in 28 nm CMOS

The paper describes a design of a prototype chip in 28 nm CMOS technology, consisting of 8 × 4 pixels with 50 μm pitch, dedicated for the precise measurement of Time-of-Arrival (ToA) and Time-over-Threshold (ToT) with a resolution within the picosecond range. To address this requirement, in-pixel Vernier time-to-digital converter (TDC) has been implemented, which utilizes two ring oscillators per pixel. Overall chip architecture is introduced as well as pixel architecture and selected simulation results. The pixel consists of a recording channel and TDC part. The recording channel is composed of an inverter-based front-end amplifier with Zimmerman feedback, a discriminator, a calibration block and a threshold setting block. TDC part includes two ring oscillators together with their calibration blocks and additional logic with counters/shift registers that allow for precise ToA measurement (using Vernier method) as well as ToT measurement (using one of the oscillators). Alternatively, single photon counting (SPC) mode can be used. Frequency of oscillators is set in three steps. First, two global 8-bit digital-to-analog converters (DACs) are used for initial setting of all ring oscillators. Then, per-oscillator capacitance bank and 6-bit DAC are used for fine setting. Simulation results of core blocks suggest that the ToA resolution on the order of tens of picoseconds may be achieved. The chips are already fabricated and are currently being prepared for measurements.

Scalable High-Speed Hybrid Complementary Integrated Circuits based on Solution-Processed Organic and Amorphous Metal Oxide Semiconductors

Solution-processed single-crystal organic semiconductors (OSCs) and amorphous metal oxide semiconductors (MOSs) are promising for high-mobility, p- and n-channel thin-film transistors (TFTs), respectively. Organic−inorganic hybrid complementary circuits hence have great potential to satisfy practical requirements; however, some chemical incompatibilities between OSCs and MOSs, such as heat and chemical resistance, conventionally make it difficult to rationally integrate TFTs based on solution-processed OSC and MOS into the same substrates. In this work, we achieved a rational integration method based on the solution-processed semiconductors by carefully managing the device configuration and the deposition and patterning techniques from materials point of view. The balanced high performances as well as the uniform fabrication of the TFTs led to densely integrated five-stage ring oscillators with the stage propagation delay of 1.3 µs, which is the fastest operation among ever reported complementary ring oscillators based on solution-processed semiconductors.