用于高速ADC的低抖动时钟稳定电路

介绍了一种用于高速ADC的低抖动时钟稳定电路.这个电路由延迟锁相环(DLL)来实现.这个DLL有两个功能:一是通过把一个时钟沿固定精确延迟半个周期,再与另一个沿组成一个新的时钟来调节时钟占空比到50%左右;二是调节时钟抖动.该电路采用0.35 μm CMOS工艺,在Cadence Spectre环境下进行仿真验证,对一个8 bit、250 Msps采样率的ADC,常温下得到的时钟抖动小于0.25 ps rms(典型的均方根).     

一款具有新颖的采样保持电路应用于脉冲式超宽带技术的欠采样型模数转换器

本文提出了一款基于CMOS 0.13um,具有新颖的采样保持电路,应用于脉冲式超宽带接收机的欠采样型模数转换器.本文主要的难点在于实现拥有远远高于奈奎斯特频率的输入信号的欠采样型模数转换器。根据我们的了解,本文是当今第二次提出当采样时钟大约在1.056GHz,输入信号超过4GHz的欠采样型模数转换器。电路设计中,我们提出了一款新颖的采样保持电路,解决了信号幅度的衰减和高频输入信号线性度的问题。一款使用零静态功耗动态失调校准比较器被进一步优化,实现了失调,速度以及功耗的要求。测试结果显示,当采样频率为1.056GHz,输入信号高达4.2GHz时,SFDR 为30.1dB。不包括缓冲器,ADC的功耗为30mW,芯片面积为0.6mm2.ADC的FoM是3.75pJ.     

A sub-sampling 4-bit 1.056-GS/s flash ADC with a novel track and hold amplifier for an IR-UWB receiver

A sub-sampling 4-bit 1.056-GS/s flash ADC with a novel track and hold amplifier(THA) in 0.13μm CMOS for an impulse radio ultra-wideband(IR-UWB) receiver is presented.The challenge is in implementing a sub-sampling ADC with ultra-high input signal that further exceeds the Nyquist frequency.This paper presents,to our knowledge for the second time,a sub-sampling ADC with input signals above 4 GHz operating at a sampling rate of 1.056 GHz.In this design,a novel THA is proposed to solve the degradation in amplitude and improve the linearity of signal with frequency increasing to giga Hz.A resistive averaging technique is carefully analyzed to relieve noise aliasing.A low-offset latch using a zero-static power dynamic offset cancellation technique is further optimized to realize the requirements of speed,power consumption and noise aliasing.The measurement results reveal that the spurious free dynamic range of the ADC is 30.1 dB even if the input signal is 4.2 GHz sampled at 1.056 GS/s.The core power of the ADC is 30 mW,excluding all of the buffers,and the active area is 0.6 mm~2.The ADC achieves a figure of merit of 3.75 pJ/conversion-step.     

12位20MS/s流水线ADC的研制

流水线结构是高速高精度ADC的首选.通过对流水线ADC的结构、MDAC电路进行了研究;提出新型采样保持开关;设计了12位20 MS/s采样率流水线ADC,并基于SMIC0.35μm混合CMOS工艺进行流片实现,测试结果表明,在测试仪器只有10位精度的情况下SFDR=65 dB,SNDR=56 dB,SNR=56.9 dB,ENOB=9.1 bit,最后对测试结果进行分析.     

Reconfigurable radio receiver with fractional sample rate converter and multi-rate ADC based on LO-derived sampling clock

A composite radio receiver back-end and digital front-end, made up of a delta-sigma analogue-to-digital converter (ADC) with a high-speed low-noise sampling clock generator, and a fractional sample rate converter (FSRC), is proposed and designed for a multi-mode reconfigurable radio. The proposed radio receiver architecture contributes to saving the chip area and thus lowering the design cost. To enable inter-radio access technology handover and ultimately software-defined radio reception, a reconfigurable radio receiver consisting of a multi-rate ADC with its sampling clock derived from a local oscillator, followed by a rate-adjustable FSRC for decimation, is designed. Clock phase noise and timing jitter are examined to support the effectiveness of the proposed radio receiver. A FSRC is modelled and simulated with a cubic polynomial interpolator based on Lagrange method, and its spectral-domain view is examined in order to verify its effect on aliasing, nonlinearity and signal-to-noise ratio, giving insight into the design of the decimation chain. The sampling clock path and the radio receiver back-end data path are designed in a 90-nm CMOS process technology with 1.2V supply.