A 14-b 12-MS/s CMOS pipeline ADC with over 100-dB SFDR

A 1.8-V 14-b 12-MS/s pseudo-differential pipeline analog-to-digital converter (ADC) using a passive capacitor error-averaging technique and a nested CMOS gain-boosting technique is described. The converter is optimized for low-voltage low-power applications by applying an optimum stage-scaling algorithm at the architectural level and an opamp and comparator sharing technique at the circuit level. Prototyped in a 0.18-/spl mu/m 6M-1P CMOS process, this converter achieves a peak signal-to-noise plus distortion ratio (SNDR) of 75.5 dB and a 103-dB spurious-free dynamic range (SFDR) without trimming, calibration, or dithering. With a 1-MHz analog input, the maximum differential nonlinearity is 0.47 LSB and the maximum integral nonlinearity is 0.54 LSB. The large analog bandwidth of the front-end sample-and-hold circuit is achieved using bootstrapped thin-oxide transistors as switches, resulting in an SFDR of 97 dB when a 40-MHz full-scale input is digitized. The ADC occupies an active area of 10 mm/sup 2/ and dissipates 98 mW.     

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.     

A digitally enhanced 1.8-V 15-bit 40-MSample/s CMOS pipelined ADC

A 1.8-V 15-bit 40-MSample/s CMOS pipelined analog-to-digital converter with 90-dB spurious-free dynamic range (SFDR) and 72-dB peak signal-to-noise ratio (SNR) over the full Nyquist band is presented. Its differential and integral nonlinearities are 0.25 LSB and 1.5 LSB, respectively, and its power consumption is 400 mW. This performance is enabled by digital background calibration of internal digital-to-analog converter (DAC) noise and interstage gain errors. The calibration achieves improvements of better than 12 dB in signal-to-noise plus distortion ratio and 20 dB in SFDR relative to the case where calibration is disabled. Other enabling features of the prototype integrated circuit (IC) include a low-latency, segmented, dynamic element-matching DAC, distributed passive input signal sampling, and asymmetric clocking to maximize the time available for the first-stage residue amplifier to settle. The IC is realized in a 0.18-/spl mu/m mixed-signal CMOS process and has a die size of 4mm/spl times/5 mm.     

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.     

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.     

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。     

An 11-Bit 45 MS/s Pipelined ADC With Rapid Calibration of DAC Errors in a Multibit Pipeline Stage

A technique to rapidly correct for both DAC and gain errors in the multibit first stage of an 11-bit pipelined ADC is presented. Using a dual-ADC based approach the digital background scheme is validated with a proof-of-concept prototype fabricated in a 1.8 V 0.18 CMOS process, where the calibration scheme improves the peak INL of the 45 MS/s ADC from 6.4 LSB to 1.1 LSB after calibration. The SNDR/SFDR is improved from 46.9 dB/48.9 dB to 60.1 dB/70 dB after calibration. Calibration is achieved in approximately 10⁴ clock cycles.     

A 1.4-V 25-Mw 600-MS/s 6-bit folding and interpolating ADC in 0.13-μm CMOS

A 600-MSample/s 6-bit folding and interpolating analog-to-digital converter (ADC) is presented. This ADC with single track-and-hold (T/H) circuits is based on cascaded folding amplifiers and input-connection-improved active interpolating amplifiers. The prototype ADC achieves 5.55 bits of the effective number of bits (ENOB) and 47.84 dB of the spurious free dynamic range (SFDR) at 10-MHz input and 4.3 bit of ENOB and 35.65 dB of SFDR at 200-MHz input with a 500 MS/s sampling rate; it achieves 5.48 bit of ENOB and 43.52 dB of SFDR at 1-MHz input and 4.66 bit of ENOB and 39.56 dB of SFDR at 30. 1-MHz input with a 600-MS/s sampling rate. This ADC has a total power consumption of 25 mW from a 1.4 V supply voltage and occupies 0.17 mm~2 in the 0.13-μm CMOS process.     

A 12-bit self-calibrating SAR ADC achieving a Nyquist 90.4-dB SFDR

This paper describes a 10 or 12 bit programmable successive approximation register ADC for bridge stress monitoring systems requiring high-resolution, high linearity, low power and small size. Its sampling rate is scalable, from 0 to 200 kS/s. The proposed ADC employs a novel time-domain comparator with offset cancellation. Prototyped in a 0.18-μm, 6MIP CMOS process, the ADC, at 12 bit, 100 kS/s, achieves a Nyquist SNDR of 68.74 dB (11.13), an SFDR of 90.36 dB, while dissipating 579.6 μW from a 1.8-V supply. The on-chip calibration improves the DNL from +0.2/?0.74 LSB to +0.23/?0.25 LSB and INL from +1.27/?0.97 LSB to +0.41/?0.4 LSB.     

A 1.2 V 10-bit 5MS/s low power CMOS cyclic ADC based on double-sampling technique

This paper presents a 1.2 V 10-bit 5MS/s low power cyclic analog-to-digital converter (ADC). The strategy to minimize the power adopts the double-sampling technique. At the front-end, a timing-skew-insensitive double-sampled Miller-capacitance-based sample-and-hold circuit (S/H) is employed to enhance the dynamic performance of the cyclic ADC. Double sampling technique is also applied to multiplying digital-to-analog converter (MDAC). This scheme provides a better power efficiency for the proposed cyclic ADC. Furthermore, bootstrapped switch is used to achieve rail-to-rail signal swing at low-voltage power supply. The prototype ADC, fabricated in TSMC 0.18 μm CMOS 1P6 M process, achieves DNL and INL of 0.32LSB and 0.45LSB respectively, while SFDR is 69.1 dB and SNDR is 58.6 dB at an input frequency of 600 kHz. Operating at 5MS/s sampling rate under a single 1.2 V power supply, the power consumption is 1.68 mW.     

A 1-V 100-MS/s 8-bit CMOS Switched-Opamp Pipelined ADC Using Loading-Free Architecture

A 1-V, 8-bit pipelined ADC is realized using multi-phase switched-opamp (SO) technique. A novel loading-free architecture is proposed to reduce the capacitive loading and to improve the speed in low-voltage SO circuits. Employing the proposed loading-free pipelined ADC architecture together with double-sampling technique and a fast-wake-up dual-input-dual-output switchable opamp, the ADC achieves 100-MS/s conversion rate, which to our knowledge is the fastest ADC ever reported at 1-V supply using SO technique, with performance comparable to that of many high-voltage switched-capacitor (SC) ADCs. Implemented in a 0.18-mum CMOS process, the ADC obtains a peak SNR of 45.2 dB, SNDR of 41.5 dB, and SFDR of 52.6 dB. Measured DNL and INL are 0.5 LSB and 1.1 LSB, respectively. The chip dissipates only 30 mW from a 1-V supply     

Background Calibration With Piecewise Linearized Error Model for CMOS Pipeline A/D Converter

A new all-digital background calibration method, using a piecewise linear model to estimate the stage error pattern, is presented. The method corrects both linear and nonlinear errors. The proposed procedure converges in a few milliseconds and requires low hardware overhead, without the need of a high-capacity ROM or RAM. The calibration procedure is tested on a 0.6- $mu{hbox {m}}$ CMOS pipeline analog-to-digital converter (ADC), which suffers from a high degree of nonlinear errors. The calibration gives improvements of 17 and 26 dB for signal-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR), respectively, for the Nyquist input signal at the sampling rate of 33 MSample/s. The calibrated ADC achieves SNDR of 70.3 dB and SFDR of 81.3 dB at 33 MSample/s, which results in a resolution of about 12 b.      

A digital background calibration technique for time-interleavedanalog-to-digital converters

A 10-bit 40-Msample/s two-channel parallel pipelined ADC with monolithic digital background calibration has been designed and fabricated in a 1 μm CMOS technology. Adaptive signal processing and extra resolution in each channel are used to carry out digital background calibration. Test results show that the ADC achieves a signal-to-noise-and-distortion ratio of 55 dB for a 0.8-MHz sinusoidal input, a peak integral nonlinearity of 0.34 LSB, and a peak differential nonlinearity of 0.14 LSB, both at a 10-bit level. The active area is 42 mm², and the power dissipation is 565 mW from a 5 V supply     

A power-efficient 10-bit 40-MS/s sub-sampling pipelined CMOS analog-to-digital converter

This paper presents a 10-bit 40-MS/s pipelined analog-to-digital converter (ADC) in a 0.13-μm CMOS process for subsampling applications. A simplified opamp-sharing scheme between two successive pipelined stages is proposed to reduce the power consumption. For subsampling, a cost-effective fast input-tracking switch with high linearity is introduced to sample the input signal up to 75 MHz. A two-stage amplifier with hybrid frequency compensation is developed to achieve both high bandwidth and large swing with low power dissipation. The measured result shows that the ADC achieves over 77 dB spurious free dynamic range (SFDR) and 57.3 dB signal-to-noise-plus-distortion ratio (SNDR) within the first Nyquist zone and maintains over 70 dB SFDR and 55.3 dB SNDR for input signal up to 75 MHz. The peak differential nonlinearity (DNL) and integral nonlinearity (INL) are ±0.2 LSB and ±0.3 LSB, respectively. The ADC consumes 15.6 mW at the sampling rate of 40 MHz from a 1.2-V supply voltage, and achieves a figure-of-merit (FOM) value of 0.22 pJ per conversion step.     

A Low-Power Low-Voltage 10-bit 100-MSample/s Pipeline A/D Converter Using Capacitance Coupling Techniques

This paper presents a low-power low-voltage 10-bit 100-MSample/s pipeline analog-to-digital converter (ADC) using capacitance coupling techniques. A capacitance coupling sample-and-hold stage achieves high SFDR with 1.0-V supply voltage at a high sampling rate. A capacitance coupling folded-cascode amplifier effectively saves the power consumption of the gain stages of the ADC in a 90-nm digital CMOS technology. The SNDR and the SFDR are 55.3 dB and 71.5 dB, respectively, and the power consumption is 33 mW     

A 3.3-V 12-b 50-MS/s A/D converter in 0.6-μm CMOS with over80-dB SFDR

A 12-b analog-to-digital converter (ADC) is optimized for spurious-free dynamic range (SFDR) performance at low supply voltage and suitable for use in modern wireless base stations. The 6-7-b two-stage pipeline ADC uses a bootstrap circuit to linearize the sampling switch of an on-chip sample-and-hold (S/H) and achieves over 80-dB SFDR for signal frequencies up to 75 MHz at 50 MSample/s (MSPS) without trimming, calibration, or dithering. INL is 1.3 LSB, differential nonlinearity (DNL) is 0.8 LSB. The 6-b and 7-b flash sub-ADCs are implemented efficiently using offset averaging and analog folding. In 0.6-μm CMOS, the 16-mm² ADC dissipates 850 mW     

A 14-b 20-Msamples/s CMOS pipelined ADC

The capacitor error-averaging technique, updated with look-ahead decision and digital correction, is used to demonstrate a 14-b 20-Msamples/s pipelined analog-to digital converter (ADC) with no trimming or calibration. The prototype ADC exhibits a differential nonlinearity (DNL) of +0.23/-0.28 least significant bit (LSB), an integral nonlinearity (INL) of +0.95/-1.06 LSB, a spurious-free dynamic range (SFDR) of 91.6 dB, and a signal-to-noise ratio (SNR) of 74.2 dB with a 1-MHz input and a 20-MHz clock. The prototype in 0.5-μm CMOS occupies an area of 4.5×2.4 mm² and consumes 720 mW at 5 V     

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.     

A 10 MS/s 11-bit 0.19 mm $^{2}$ Algorithmic ADC With Improved Clocking Scheme

A 10 MS/s 11-bit algorithmic ADC with an active area of 0.19$~{hbox{mm}}^{2}$ is presented. Using an improved clocking scheme, this design overcomes the speed limit of algorithmic ADCs. The proposed ADC employs amplifier sharing, DC offset cancellation, and input memory effect suppression, resulting in reduced area and power, and high linearity. The ADC implemented in a 0.13$~mu{hbox{m}}$ thick gate-oxide CMOS process achieves 69 dB SFDR, 58 dB SNR, and 56 dB SNDR, while consuming 3.5 mA from a 3 V supply.