Integral nonlinearity

About: Integral nonlinearity is a research topic. Over the lifetime, 1295 publications have been published within this topic receiving 21919 citations.

A 12-bit 80-MSample/s pipelined ADC with bootstrapped digital calibration

Abstract: This paper presents a prototype analog-to-digital converter (ADC) that uses a calibration algorithm to adaptively overcome constant closed-loop gain errors, closed-loop gain variation, and slew-rate limiting. The prototype consists of an input sample-and-hold amplifier (SHA) that can serve as a calibration queue, a 12-bit 80-MSample/s pipelined ADC, a digital-to-analog converter (DAC) for calibration, and an embedded custom microprocessor, which carries out the calibration algorithm. The calibration is bootstrapped in the sense that the DAC is used to calibrate the ADC, and the ADC is used to calibrate the DAC. With foreground calibration, test results show that the peak differential nonlinearity (DNL) is -0.09 least significant bits (LSB), and the peak integral nonlinearity (INL) is -0.24LSB. Also, the maximum signal-to-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR) are 71.0 and 79.6dB with a 40-MHz sinusoidal input, respectively. The prototype occupies 22.6 mm/sup 2/ in a 0.25-/spl mu/m CMOS technology and dissipates 755 mW from a 2.5-V supply.

A self-trimming 14-b 100-MS/s CMOS DAC

Abstract: A 14-b 100-MS/s CMOS digital-analog converter (DAC) designed for high static and dynamic linearity is presented. The DAC is based on a central core of 15 thermometer decoded MSBs, 31 thermometer decoded upper LSBs (ULSBs) and 31 binary decoded lower LSBs (LLSBs). The static linearity corresponding to the 14-b specification is obtained by means of a true background self-trimming circuit which does not use additional current sources to replace the current source being measured during self-trimming. The dynamic linearity of the DAC is enhanced by a special track/attenuate output stage at the DAC output which tracks the DAC current outputs when they have settled but attenuates them for a half-clock cycle after the switching instant. The DAC occupies 3.44 mm/spl times/3.44 mm in a 0.35-/spl mu/m CMOS process, and is functional at up to 200 MS/s, with best dynamic performance obtained at 100 MS/s. At 100 MS/s, power consumption is 180 mW from a 3.3-V power supply, and 210 mW at 200 MS/s.

A Local Passive Time Interpolation Concept for Variation-Tolerant High-Resolution Time-to-Digital Conversion

Abstract: Time-to-digital converters (TDCs) are promising building blocks for the digitalization of mixed-signal functionality in ultra-deep-submicron CMOS technologies. A short survey on state-of-the-art TDCs is given. A high-resolution TDC with low latency and low dead-time is proposed, where a coarse time quantization derived from a differential inverter delay-line is locally interpolated with passive voltage dividers. This high-resolution TDC is monotonic by construction which makes the concept very robust against process variations. The feasibility is demonstrated by a 90 nm demonstrator which uses a 4x interpolation and provides a time domain resolution of 4.7 ps. An integral nonlinearity of 1.2 LSB and a differential nonlinearity of 0.6 LSB are achieved. The resolution restrictions imposed by an uncertainty of the stop signal and local variations are derived theoretically.

A simplified polynomial-fitting algorithm for DAC and ADC BIST

Abstract: An accurate and simple method is introduced for determining the third order polynomial that best fits a set of data points containing random noise. The coefficients of the polynomial are translated into offset, gain, and harmonic distortion for an analog-to-digital converter (ADC) driven by a digital-to-analog converter (DAC) or other appropriate signal source. The algorithm is efficient enough to be implemented as a built-in self-test for an IC, and is particularly suitable for sigma-delta converters.

On-chip ramp generators for mixed-signal BIST and ADC self-test

Abstract: A practical approach to generate on-chip precise and slow analog ramps, intended for time-domain analog testing, monotonicity and histogram-based tests of ADCs is proposed. The technique uses an analog discrete-time adaptive scheme to calibrate the ramp generator. The lowest slope is 0.4V/ms. Three implementations are presented for different levels of accuracy and complexity. Measurement results show excellent accuracy and programmability, up to only 0.6% of slope error and maximum integral nonlinearity error of /spl plusmn/175/spl mu/V. Experimental and theoretical results are in good agreement.