A CMOS switch-capacitor 14-bit 100 Msps pipeline ADC with over 90 dB SFDR

This article presents a design of 14-bit 100?Msamples/s pipelined analog-to-digital converter (ADC) implemented in 0.18?µm CMOS. A charge-sharing correction (CSC) is proposed to remove the input-dependent charge-injection, along with a floating-well bulk-driven technique, a fast-settling reference generator and a low-jitter clock circuit, guaranteeing the high dynamic performance of the ADC. A scheme of background calibration minimises the error due to the capacitor mismatch and opamp non-ideality, ensuring the overall linearity. The measured results show that the prototype ADC achieves spurious-free dynamic range (SFDR) of 91?dB, signal-to-noise-and-distortion ratio (SNDR) of 73.1?dB, differential nonlinearity (DNL) of +0.61/?0.57?LSB and integrated nonlinearity (INL) of +1.1/?1.0?LSB at 30?MHz input and maintains over 78?dB SFDR and 65?dB SNDR up to 425?MHz, consuming 223?mW totally.     

Nested Digital Background Calibration of a 12-bit Pipelined ADC Without an Input SHA

To reduce power dissipation, the input sample-and-hold amplifier (SHA) is eliminated in a pipelined analog-to-digital converter (ADC) with nested background calibration. The nested architecture calibrates the pipelined ADC with an algorithmic ADC that is also calibrated. Without an input SHA, a timing difference between the sampling instants of the two ADCs creates an error that interferes with calibration of the pipelined ADC. This problem is overcome with digital background timing compensation. It uses a differentiator with fixed coefficients to build an adaptive interpolator. With a 58-kHz sinusoidal input, the 12-bit 20-Msample/s pipelined ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 70.2 dB, a spurious-free dynamic range (SFDR) of 80.3 dB, and an integral nonlinearity (INL) of 0.75 least significant bit (LSB). With a 9-MHz input, the SNDR is 64.2 dB, and the SFDR is 78.3 dB. About 2 million samples or 0.1 s are required for convergence. The prototype occupies 7.5 mm² in 0.35-mum CMOS and dissipates 231 mW from 3.3 V, which is 23 mW less than in a previous prototype with the input SHA.     

An 80-MS/s 14-bit pipelined ADC featuring 83 dB SFDR

An 80-MS/s 14-bit pipelined analog-to-digital converter (ADC) is presented in this paper. After gain error and offset extraction from prototype measurement, the improved circuit achieves spurious free dynamic range (SFDR) of 82.9 dB and signal-to-noise-and-distortion ratio (SINAD) of 64.1 dB for a 30.5 MHz input, maintained within 6 dB performance deterioration up to 170 MHz input. Differential nonlinearity (DNL) is 0.66 LSB and integral nonlinearity (INL) is 2.5 LSB. Low-jitter clock amplifier and buffers with balanced loads are used to reduce the jitter and skew between different stages. An on-chip voltage reference generator is schemed with low impedance to reduce noise and spurs of reference signals. The ADC is fabricated in a 0.18-μm CMOS process with core area of 3.86 mm², and consumes 518 mW at 1.8 V supply.     

A low power 12-b 40-MS/s pipeline ADC

This paper describes a 12-bit, 40-MS/s pipelined A/D converter (ADC) which is implemented in 0.18-μm CMOS process drawing 76-mW power from 3.3-V supply. Multi-bit architectures as well as telescopic operational transconductance amplifiers (OTAs) are adopted in all pipeline stages for good power efficiency. In the first two stages,particularly, 3-bit/stage architectures are used to improve the ADC's linearity performance. The ADC is calibration-free and achieves a DNL of less than 0.51 LSB and an INL of less than 1 LSB. The SNDR performance is above 67 dB below Nyquist. The 80-dB SFDR performance is maintained within 1 dB for input frequencies up to 49 MHz at full sampling rate.     

一个高线性13位流水线CMOS A/D转换器

介绍了一个采用多种电路设计技术来实现高线性13位流水线A/D转换器.这些设计技术包括采用无源电容误差平均来校准电容失配误差、增益增强(gain-boosting)运放来降低有限增益误差和增益非线性,自举(bootstrapping)开关来减小开关导通电阻的非线性以及抗干扰设计来减弱来自数字供电的噪声.电路采用0.18μm CMOS工艺实现,包括焊盘在内的面积为3.2mm2.在2.5MHz采样时钟和2.4MHz输入信号下测试,得到的微分非线性为-0.18/0.15LSB,积分非线性为-0.35/0.5LSB,信号与噪声加失真比(SNDR)为75.7dB,无杂散动态范围(SFDR)为90.5dBc;在5MHz采样时钟和2.4MHz输入信号下测试,得到的SNDR和SFDR分别为73.7dB和83.9dBc.所有测试均在2.7V电源下进行,对应于采样率为2.5MS/s和5Ms/s的功耗(包括焊盘驱动电路)分别为21mW和34mW.     

A 12-bit 20-Msample/s pipelined analog-to-digital converter with nested digital background calibration

A 12-bit 20-Msample/s pipelined analog-to-digital converter (ADC) is calibrated in the background using an algorithmic ADC, which is itself calibrated in the foreground. The overall calibration architecture is nested. The calibration overcomes the circuit nonidealities caused by capacitor mismatch and finite operational amplifier (opamp) gain both in the pipelined ADC and the algorithmic ADC. With a 58-kHz sinusoidal input, test results show that the pipelined ADC achieves a peak signal-to-noise-and-distortion ratio (SNDR) of 70.8 dB, a peak spurious-free dynamic range (SFDR) of 93.3 dB, a total harmonic distortion (THD) of -92.9 dB, and a peak integral nonlinearity (INL) of 0.47 least significant bit (LSB). The total power dissipation is 254 mW from 3.3 V. The active area is 7.5 mm/sup 2/ in 0.35-/spl mu/m CMOS.     

A 10-b 120-Msample/s time-interleaved analog-to-digital converter with digital background calibration

Digital calibration using adaptive signal processing corrects for offset mismatch, gain mismatch, and sample-time error between time-interleaved channels in a 10-b 120-Msample/s pipelined analog-to-digital converter (ADC). Offset mismatch between channels is overcome with a random chopper-based offset calibration. Gain mismatch and sample-time error are overcome with correlation-based algorithms, which drive the correlation between a signal and its chopped image or its chopped and delayed image to zero. Test results show that, with a 0.99-MHz sinusoidal input, the ADC achieves a peak signal-to-noise-and-distortion ratio (SNDR) of 56.8 dB, a peak integral nonlinearity of 0.88 least significant bit (LSB), and a peak differential nonlinearity of 0.44 LSB. For a 39.9-MHz sinusoidal input, the ADC achieves a peak SNDR of 50.2 dB. The active area is 5.2 mm/sup 2/, and the power dissipation is 234 mW from a 3.3-V supply.     

A 12-bit 40 MS/s pipelined ADC with over 80 dB SFDR

This paper describes a 12-bit 40 MS/s calibration-free pipelined analog-to-digital converter (ADC), which is optimized for high spurious flee dynamic range (SFDR) performance and low power dissipation. With a 4.9 MHz sine wave input, the prototype ADC implemented in a 0.18-μm 1P6M CMOS process shows measured differential nonlinearity and integral nonlinearity within 0.78 and 1.32 least significant bits at the 12-bit level without any trimming or calibration. The ADC, with a total die area of 3. 1 × 2.1 mm~2, demonstrates a maximum signal-to-noise distortion ratio (SNDR) and SFDR of 66.32 and 83.38 dB, respectively, at a 4.9 MHz analog input and a power consumption of 102 mW from a 1.8 V supply.     

Digital background calibration of charge pump based pipelined ADC

In the presented work, digital background calibration of a charge pump based pipelined ADC is presented. A 10-bit 100 MS/s pipelined ADC is designed using TSMC 0.18 µm CMOS technology operating on a 1.8 V power supply voltage. A power efficient opamp-less charge pump based technique is chosen to achieve the desired stage voltage gain of 2 and digital background calibration is used to calibrate the inter-stage gain error. After calibration, the ADC achieves an SNDR of 66.78 dB and SFDR of 79.3 dB. Also, DNL improves to +0.6/–0.4 LSB and INL improves from +9.3/–9.6 LSB to within ±0.5 LSB, consuming 16.53 mW of power.     

一种数字CMOS工艺制造的10位100MS/s流水线ADC

介绍了采用0.18μm数字工艺制造、工作在3.3V下、10位100MS/s转换速率的流水线模数转换器。提出了一种适用于1.5位MDAC的新的金属电容结构,并且使用了高带宽低功耗运算放大器、对称自举开关和体切换的PMOS开关来提高电路性能。芯片已经通过流片验证,版图面积为1.35mm×0.99mm,功耗为175mW。14.7MS/s转换速率下测得的DNL和INL分别为0.2LSB和0.45LSB,100MS/s转换速率下测得的DNL和INL分别为1LSB和2.7LSB,SINAD为49.4dB,SFDR为66.8dB。     

A 12-Bit 200-MHz CMOS ADC

A pipelined ADC incorporates a blind LMS calibration algorithm to correct for capacitor mismatches, residue gain error, and op amp nonlinearity. The calibration applies 128 levels and their perturbed values, computing 128 local errors across the input range and driving the mean square of these errors to zero. Fabricated in 90-nm digital CMOS technology, the ADC achieves a DNL of 0.78 LSB, an INL of 1.7 LSB, and an SNDR of 62 dB at an analog input frequency of 91 MHz while consuming 348 mW from a 1.2 V supply.      

A 0.9-V 12-mW 5-MSPS algorithmic ADC with 77-dB SFDR

An ultra-low-voltage CMOS two-stage algorithm ADC featuring high SFDR and efficient background calibration is presented. The adopted low-voltage circuit technique achieves high-accuracy high-speed clocking without the use of clock boosting or bootstrapping. A resistor-based input sampling branch demonstrates high linearity and inherent low-voltage operation. The proposed background calibration accounts for capacitor mismatches and finite opamp gain error in the MDAC stages via a novel digital correlation scheme involving a two-channel ADC architecture. The prototype ADC, fabricated in a 0.18 /spl mu/m CMOS process, achieves 77-dB SFDR at 0.9 V and 5MSPS (30 MHz clocking) after calibration. The measured SNR, SNDR, DNL, and INL at 80 kHz input are 50 dB, 50 dB, 0.6 LSB, and 1.4 LSB, respectively. The total power consumption is 12 mW, and the active die area is 1.4 mm/sup 2/.     

一种12位50MS/s CMOS流水线A/D转换器

采用TSMC 0.18μm 1P6M工艺设计了一个12位50 MS/s流水线A/D转换器（ADC）。为了减小失真和降低功耗,该ADC利用余量增益放大电路（MDAC）内建的采样保持功能,去掉了传统的前端采样保持电路;采用时间常数匹配技术,保证输入高频信号时,ADC依然能有较好的线性度;利用数字校正电路降低了ADC对比较器失调的敏感性。使用Cadence Spectre对电路进行仿真。结果表明,输入耐奎斯特频率的信号时,电路SNDR达到72.19 dB,SFDR达到88.23 dB。当输入频率为50 MHz的信号时,SFDR依然有80.51 dB。使用1.8 V电源电压供电,在50 MHz采样率下,ADC功耗为128 mW。     

A Low Power Pipelined ADC Using Capacitor and Opamp Sharing Technique With a Scheme to Cancel the Effect of Signal Dependent Kickback

A new capacitor and opamp sharing technique that enables a very efficient low-power pipeline ADC design is proposed. A new method to cancel the effect of signal-dependent kick-back or memory effect in capacitors in the absence of a sample and hold is also presented. Fabricated in a 0.18 $mu{rm m}$ CMOS process, the prototype 11-bit pipelined ADC occupies 2.2 ${rm mm}^{2}$ of active die area and achieves 66.7 dB SFDR and 53.2 dB SNDR when a 1 MHz input signal is digitized at 80 MS/s. The SFDR and SNDR are unchanged for a 50 MHz input signal. The prototype ADC consumes 36 mW at 1.8 V supply, of which the analog portion consumes 24 mW.      

1.8Vpp 250MS/s低谐波失真流水线ADC

采用40nm CMOS工艺设计了一款在250MS/s采样率下具有1.8Vpp满摆幅和低谐波失真性能的流水线ADC（Analog-to-Digital Converter）.针对传统源跟随器结构的输入缓冲器在大摆幅下驱动大采样电容时线性度恶化的问题,采用了改进型电流注入技术和漏端电压自举技术.ADC中实现采样和电荷转移功能的开关采用薄栅器件设计,其工作电压由片上LDO（Low Dropout Regulator）提供,在降低开关寄生和电荷注入的同时保障了器件的可靠性.测试结果表明,对于10.1MHz单音输入,该ADC在-1dBFS下的信噪失真比、无杂散动态范围和总谐波失真分别为68.3dB、76.4dBc、-75.1dBc,在-1.57dBFS下的信噪失真比、无杂散动态范围和总谐波失真分别达68.3dB、80.1dBc、-78.6dBc.     

A 1-GS/s 6-bit folding and interpolating ADC in 0.13-μm CMOS

A 1-GS/s 6-bit two-channel time-interleaved folding and interpolating analog-to-digital converter (ADC) is presented in this article. For low voltage applications, input-connection-improved active interpolating amplifiers and cascaded folding amplifiers have been applied. A single front-end track-and-hold (T/H) circuit is used to avoid the sampling-time mismatches between the channels. When supplied with 1.4 V, the circuit achieves signal-to-noise-plus-distortion ratio (SNDR) of 30.74 dB and spurious free dynamic range (SFDR) of 36.91 dB and consumes a power of 66 mW with 500-MHz input and 1-GS/s sampling rate. Differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.57 and 0.81 LSB, respectively. The figure of merit (FoM) is 1.75 pJ/conversionstep. The ADC circuit is prototyped in 0.13-μm CMOS process and occupies a core area of 0.45 mm².     

A 1-GHz signal bandwidth 6-bit CMOS ADC with power-efficient averaging

A 2-GS/s 6-bit ADC with time-interleaving is demonstrated in 0.18-/spl mu/m one-poly six-metal CMOS. A triple-cross connection method is devised to improve the offset averaging efficiency. Circuit techniques, enabling a state-of-the-art figure-of-merit of 3.5 pJ per conversion step, are discussed. The peak DNL and INL are measured as 0.32 LSB and 0.5 LSB, respectively. The SNDR and SFDR have achieved 36 and 48dB, respectively, with 4 MHz input signal. Near Nyquist input frequencies, the SNDR and SFDR maintain above 30 and 35.5dB, respectively, up to 941 MHz. The complete ADC, including front-end track-and-hold amplifiers and clock buffers, consumes 310 mW from a 1.8-V supply while operating at 2-GHz conversion rate. The prototype ADC occupies an active chip area of 0.5 mm/sup 2/.     

A 14-bit 125 MS/s IF/RF Sampling Pipelined ADC With 100 dB SFDR and 50 fs Jitter

This paper describes a 14-bit, 125 MS/s IF/RF sampling pipelined A/D converter (ADC) that is implemented in a 0.35$muhbox m$BiCMOS process. The ADC has a sample-and-hold circuit that is integrated in the first pipeline stage, which removes the need for a dedicated sample-and-hold amplifier (i.e., “SHA-less”). It also has a sampling buffer that is turned off during the hold clock phases to save power. To accurately estimate and minimize the clock jitter, a new jitter simulation technique was used whose results were verified on silicon. The measured silicon results indicate the highest published IF sampling performance to date and prove the viability of the “SHA-less” architecture for IF/RF sampling ADCs. The ADC is calibration-free and achieves a DNL of less than 0.2 LSB and INL of 0.8 LSB. The SNR is 75 dB below Nyquist, and stays above 71 dB up to 500 MHz. The low-frequency SFDR is about 100 dB, and stays above 90 dB up to about 300 MHz. This is also the first ADC to achieve 14-bit level performance for input signal frequencies up to 500 MHz and to have a total RMS jitter of only 50 fs.     

A 2.5-V 10-b 120-MSample/s CMOS pipelined ADC based on merged-capacitor switching

This work describes a 10-b multibit-per-stage pipelined CMOS analog-to-digital converter (ADC) incorporating the merged-capacitor switching (MCS) technique. The proposed MCS technique improves the signal processing speed and resolution of the ADC by reducing the required number of unit capacitors by half in comparison to a conventional ADC. The ADC resolution based on the proposed MCS technique can be extended further by employing a commutated feedback-capacitor switching (CFCS) technique. The prototype ADC achieves better than 53-dB signal-to-noise-and-distortion ratio (SNDR) at 120 MSample/s and 54-dB SNDR and 68-dB spurious-free dynamic range (SFDR) for input frequencies up to Nyquist at 100 MSample/s. The measured differential and integral nonlinearities of the prototype are within /spl plusmn/0.40 LSB and /spl plusmn/0.48 LSB, respectively. The ADC fabricated in a 0.25-/spl mu/m CMOS occupies 3.6 mm/sup 2/ of active die area and consumes 208 mW under a 2.5-V power supply.     

A 1.8-V 67-mW 10-bit 100-MS/s pipelined ADC using time-shifted CDS technique

A time-shifted correlated double sampling (CDS) technique is proposed in the design of a 10-bit 100-MS/s pipelined ADC. This technique significantly reduces the finite opamp gain error without compromising the conversion speed, allowing the active opamp blocks to be replaced by simple cascoded CMOS inverters. Both high-speed and low-power operation is achieved without compromising the accuracy requirement. An efficient common-mode voltage control is introduced for pseudodifferential architecture which can further reduce power consumption. Fabricated in a 0.18-/spl mu/m CMOS process, the prototype 10-bit pipelined ADC occupies 2.5 mm/sup 2/ of active die area. With 1-MHz input signal, it achieves 65-dB SFDR and 54-dB SNDR at 100MS/s. For 99-MHz input signal, the SFDR and SNDR are 63 and 51 dB, respectively. The total power consumption is 67 mW at 1.8-V supply, of which analog portion consumes 45 mW without any opamp current scaling down the pipeline.