A 10-bit Charge-Redistribution ADC Consuming 1.9 μW at 1 MS/s

This paper presents a 10 bit successive approximation ADC in 65 nm CMOS that benefits from technology scaling. It meets extremely low power requirements by using a charge-redistribution DAC that uses step-wise charging, a dynamic two-stage comparator and a delay-line-based controller. The ADC requires no external reference current and uses only one external supply voltage of 1.0 V to 1.3 V. Its supply current is proportional to the sample rate (only dynamic power consumption). The ADC uses a chip area of approximately 115--225 μm2. At a sample rate of 1 MS/s and a supply voltage of 1.0 V, the 10 bit ADC consumes 1.9 μW and achieves an energy efficiency of 4.4 fJ/conversion-step

A Coupled Sawtooth Oscillator Combining Low Jitter With High Control Linearity

A new type of relaxation oscillator is presented that combines excellent control linearity with low timing jitter. By using an alternative for the Schmitt trigger, the jitter caused by threshold level noise can be significantly reduced compared to a conventional relaxation oscillator, under equal conditions of control linearity. Circuits realized in a 0.8-μm CMOS process show a typical measured distortion in the control characteristic of HD2 = -67 dB and HD3 = -90 dB (Δf = 500 KHz), without using any feedback linearization techniques. The measured phase noise is -102 dBc/Hz at 10-kHz offset at fosc = 1.5 MHz (65-ppm rms jitter) for a total supply current of 360 μA

A power-efficient audio amplifier combining switching and linear techniques

Integrated class-D audio amplifiers are very power efficient but require an external LC reconstruction filter, which prevents further integration. Also due to this filter, large feedback factors are hard to realize, so that the load influences the distortion and transfer characteristics. The 30 W amplifier presented in this paper consists of a switching part that contains a much simpler filter and a linear part that ensures a low distortion and flat frequency response. The switching part of the amplifier was integrated in a BCD process. Combined with a linear part and with a loudspeaker as load, it has a flat frequency response ±0.3 dB, a dissipation that is up to five times lower than a traditional class-AB audio amplifier, and a distortion of <0.02% over power and frequency rang