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 systematic design approach for low-power 10-bit 100 MS/s pipelined ADC

A systematic design approach for low-power 10-bit, 100 MS/s pipelined analog-to-digital converter (ADC) is presented. At architectural level various per-stage-resolution are analyzed and most suitable architecture is selected for designing 10-bit, 100 MS/s pipeline ADC. At Circuit level a modified wide-bandwidth and high-gain two-stage operational transconductance amplifier (OTA) proposed in this work is used in track-and-hold amplifier (THA) and multiplying digital-to-analog converter (MDAC) sections, to reduce power consumption and thermal noise contribution by the ADC. The signal swing of the analog functional blocks (THA and MDAC sections) is allowed to exceed the supply voltage (1.8 V), which further increases the dynamic range of the circuit. Charge-sharing comparator is proposed in this work, which reduces the dynamic power dissipation and kickback noise of the comparator circuit. The bootstrap technique and bottom plate sampling technique is employed in THA and MDAC sections to reduce the nonlinearity error associated with the input signal resulting in a signal-to-noise-distortion ratio of 58.72/57.57 dB at 2 MHz/Nyquist frequency, respectively. The maximum differential nonlinearity (DNL) is +0.6167/−0.3151 LSB and the maximum integral nonlinearity (INL) is +0.4271/−0.4712 LSB. The dynamic range of the ADC is 58.72 dB for full-scale input signal at 2 MHz input frequency. The ADC consumes 52.6 mW at 100 MS/s sampling rate. The circuit is implemented using UMC-180 nm digital CMOS technology.     

A 0.5-V 8-bit 10-Ms/s Pipelined ADC in 90-nm CMOS

This paper presents a pipelined analog-to-digital converter (ADC) operating from a 0.5-V supply voltage. The ADC uses true low-voltage design techniques that do not require any on-chip supply or clock voltage boosting. The switch OFF leakage in the sampling circuit is suppressed using a cascaded sampling technique. A front-end signal-path sample-and-hold amplifier (SHA) is avoided by using a coarse auxiliary sample and hold (S/H) for the sub-ADC and by synchronizing the sub-ADC and pipeline-stage sampling circuit. A 0.5-V operational transconductance amplifier (OTA) is presented that provides inter-stage amplification with an 8-bit performance for the pipelined ADC operating at 10 Ms/s. The chip was fabricated on a standard 90 nm CMOS technology and measures 1.2 mm times 1.2 mm. The prototype chip has eight identical stages and stage scaling was not used. It consumes 2.4 mW for 10-Ms/s operation. Measured peak SNDR is 48.1 dB and peak SFDR is 57.2 dB for a full-scale sinusoidal input. Maximal integral nonlinearity and differential nonlinearity are 1.19 and 0.55 LSB, respectively.     

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.     

一个59mW 10位40MHz流水线A/D转换器

设计了一个工作在3.0V的10位40MHz流水线A/D转换器,采用了时分复用运算放大器,低功耗的增益自举telescopic运放,低功耗动态比较器,器件尺寸逐级减小优化功耗.在40MHz的采样时钟,0.5MHz的输入信号的情况下测试,可获得8.1位有效精度,最大积分非线性为2.2LSB,最大微分非线性为0.85LSB,电路用0.25μm CMOS工艺实现,面积为1.24mm2,功耗仅为59mW,其中同时包括为A/D转换器提供基准电压和电流的一个带隙基准源和缓冲电路.     

A low voltage-power 13-bit 16 MSPS CMOS pipelined ADC

A low voltage-power, 13-bit and 16 MSPS analog-to-digital converter (ADC) was implemented in 0.25-/spl mu/m one-poly five-metal standard CMOS process with MIM capacitors. This ADC used a constant-gm switch to improve the nonlinear effect and a telescopic operational transconductance amplifier with a wide-swing biasing technique for power saving and low supply voltage operation. The converter achieved a peak SNDR of 59.2 dB with 16.384 MSPS, a low supply voltage of 1.3V, and Nyquist input frequency of 8.75 MHz. The static INL of /spl plusmn/2.0 LSB and DNL of /spl plusmn/0.5 LSB were obtained. The total power consumption of this converter was 78 mW. This chip occupied 3.4 mm /spl times/ 3.6 mm area.     

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 100-MS/s 8-b CMOS subranging ADC with sustained parametricperformance from 3.8 V down to 2.2 V

A 100-MS/s 8-b CMOS analog-to-digital converter (ADC) designed for very low supply voltage and power dissipation is presented. This single-ended-input ADC is based on the unified two-step subranging architecture, which processes the coarse and fine decisions in identical signal paths to maximize their matching. However, to minimize power and area, the coarse-to-fine overlap correction has been aggressively reduced to only one LSB. The ADC incorporates five established design techniques to maximize performance: bottom-plate sampling, distributed sampling, autozeroing, interpolation, and interleaving. Very low voltage operation required for a general purpose ADC was obtained with four additional and new circuit techniques. These are a dual-gain first-stage amplifier, differential T-gate boosting, a supply independent delay generator, and a digital delay-locked-loop controlled output driver. For a clock rate of 100 MS/s, 7.0 (7.3) effective bits for a 50 MHz (10 MHz) input are maintained from 3.8 V down to 2.2 V. At 2.2 V, this 100-MS/s converter dissipates 75 mW plus 9 mW for the reference ladder. For a typical supply of 2.7 V, it consumes just 1 mW per MS/s over the 10-160-MS/s clock frequency range. Differential nonlinearity below 0.5 LSB is maintained from 2.7 V down to 2.2 V, and it degrades only slightly to 0.8 LSB at 3.8-V supply. The converter is implemented in a 0.35-μm CMOS process, with double-poly capacitors and no low-threshold devices     

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.     

Low-power CMOS fully-folding ADC with a mixed-averaging distributed T/H circuit

This paper describes an 8-bit 125 Mhzlow-powerCMOS fully-foldinganalog-to-digital converter(ADC).A novel mixed-averaging distributed T/H circuit is proposed to improve the accuracy. Folding circuits are not only used in the fine converter but also in the coarse one and in the bit synchronization block to reduce the number of comparators for low power. This ADC is implemented in 0.5μm CMOS technology and occupies a die area of 2 × 1.5 mm~2. The measured differential nonlinearity and integral nonlinearity are 0.6 LSB/-0.8 LSB and 0.9 LSB/-1.2 LSB, respectively. The ADC exhibits 44.3 dB of signal-to-noise plus distortion ratio and 53.5 dB of spurious-free dynamic range for 1 MHz input sine-wave. The power dissipation is 138 mW at a sampling rate of 125 MHz at a 5 V supply.     

A low power 12-bit 30 MSPS CMOS pipeline ADC with on-chip voltage reference buffer

A 12-bit 30 MSPS pipeline analog-to-digital converter(ADC) implemented in 0.13-μm 1P8M CMOS technology is presented.Low power design with the front-end sample-and-hold amplifier removed is proposed.Except for the first stage,two-stage cascode-compensated operational amplifiers with dual inputs are shared between successive stages to further reduce power consumption.The ADC presents 65.3 dB SNR,75.8 dB SFDR and 64.6 dB SNDR at 5 MHz analog input with 30.7 MHz sampling rate.The chip dissipates 33.6 mW from 1.2 V power supply.FOM is 0.79 pJ/conv step.     

A wideband calibration-free 1.5-GS/s 8-bit analog-to-digital converter with low latency

This article presents a wideband calibration-free 8-bit analog-to-digital converter (ADC) with low latency. The ADC employs a two-stage cascaded folding and interpolating architecture. A high-linearity and wideband track-and-hold amplifier combined with a low-parasitic-capacitance folding amplifier is employed to improve the performance. A binary-ROM with “keep-alive” current is proposed to guarantee no miscode when large bit-rate is input. When the sampling frequency is 1.5 GHz, the ADC achieves +0.29/?0.20 LSB DNL and 0.90 LSB INL. The ADC’s effective-number-of-bit and spur-free-dynamic-range are 7.0 bit and 51.8 dB respectively at 230 MHz input. The effective-resolution-bandwidth exceeds the second Nyquist zone up to 1.8 GHz. All of this makes this ADC suitable for wideband digital receiver system.     

A 10-bit 50 MS/s Pipelined ADC With Capacitor-Sharing and Variable-$g_{m}$ Opamp

A pipelined analog-to-digital converter (ADC) architecture which is suitable for low power and small area is presented. The prototype ADC achieves 10-bit resolution with only two opamps by removing a front-end sample-and-hold amplifier (SHA) and sharing an opamp between two successive pipeline stages. The errors from the absence of SHA and opamp-sharing are greatly reduced by the proposed techniques and circuits. Further reduction of power and area is achieved by using a capacitor-sharing technique and variable- $g_{m}$ opamp. The ADC is implemented in 0.18 $muhbox{m}$ CMOS technology and occupies a die area of 0.86 ${hbox{mm}}^{2}$. The differential and integral nonlinearity of the ADC are less than 0.39 LSB and 0.81 LSB, respectively, at full sampling rate. The ADC achieves 56.2 dB signal-to-noise plus distortion ratio, 72.7 dB spurious free dynamic range, ${-}$66.2 $~$dB total harmonic distortion, 9.03 effective number of bits for a Nyquist input at full sampling rate, and consumes 12 mW from a 1.8 V supply.      

A 3-V 340-mW 14-b 75-Msample/s CMOS ADC with 85-dB SFDR at Nyquistinput

This paper describes the design of a 14-b 75-Msample/s pipeline analog-to-digital converter (ADC) implemented in a 0.35-μm double-poly triple-metal CMOS process. The ADC uses a 4-b first stage to relax capacitor-matching requirements, buffered bootstrapping to reduce signal-dependent charge injection, and a flip-around track-and-hold amplifier with wide common-mode compliance to reduce noise and power consumption. It achieves 14-b accuracy without calibration or dithering. Typical differential nonlinearity is 0.6 LSB, and integral nonlinearity is 2 LSB. The ADC also achieves 73-dB signal-to-noise ratio, and 85-dB spurious-free dynamic range over the first Nyquist band. The 7.8-mm² ADC operates with a 2.7- to 3.6-V supply, and dissipates 340 mW at 3 V     

A 600-MS/s 5-bit pipeline A/D converter using digital reference calibration

The design of a 600-MS/s 5-bit analog-to-digital (A/D) converter for serial-link receivers has been investigated. The A/D converter uses a closed-loop pipeline architecture. The input capacitance is only 170 fF, making it suitable for interleaving. To maintain low power consumption and increase the sampling rate beyond the amplifier settling limit, the paper proposes a calibration technique that digitally adjusts the reference voltage of each pipeline stage. Differential input swing is 400 mV/sub p-p/ at 1.8-V supply. Measured performance includes 25.6 dB and 19 dB of SNDR for 0.3-GHz and 2.4-GHz input frequencies at 600 MS/s for the calibrated A/D converter. The suggested calibration method improves SNDR by 4.4 dB at 600 MS/s with /spl plusmn/0.35 LSB of DNL and /spl plusmn/0.15 LSB of INL. The 180 /spl times/ 1500 /spl mu/m/sup 2/ chip is fabricated in a 0.18-/spl mu/m standard CMOS technology and consumes 70 mW of power at 600 MS/s.     

A 10-b 20-Msample/s low-power CMOS ADC

A single-ended input but internally differential 10 b, 20 Msample/s pipelined analog-to-digital converter (ADC) is demonstrated with 4 mW per stage using a single 5 V supply. The prototype ADC made of an input sample and hold (S/H) plus 8 identical unscaled pipelined stages consumes 50 mW including power consumed by a bias generator and two internal buffer amplifiers driving common-mode bias lines. Key circuits developed for this low-power ADC are a dynamic comparator with a capacitive reference voltage divider that consumes no static power, a source-follower buffered op amp that achieves wide bandwidth using large input devices, and a self-biased cascode biasing circuit that tracks power supply variation. The ADC implemented using a double-poly 1.2 μm CMOS technology exhibits a DNL of ±0.65 LSB and a SNDR of 54 dB while sampling at 20 MHz. The chip die area is 13 mm²     

Algorithmic ADC operating with a single reference voltage for PLL-based chemical sensing applications

This paper deals with the design of an algorithmic switched-capacitor analog-to-digital converter (ADC), operating with a single reference voltage, a single-ended amplifier, a single-ended comparator, and presenting a small input capacitance. The ADC requires two clock phases per conversion bit and N clock cycles to resolve the N-bits. The ADC achieves a measured peak signal-to-noise-ratio (SNR) of 49.9 dB and a peak signal-to-noise-and-distortion-ratio (SNDR) of 46.7 dB at P_in = ?6dBFS with a sampling rate of 0.25 MS/s. The measured differential-non-linearity and integral-non-linearity are within +0.6/?0.5 and +0.2/?0.5 LSB, respectively. The ADC power consumption is 300 μW and it is implemented in 90 nm CMOS technology with a single power supply of 1.2 V. The ADC saves power at system-level by requiring only a single reference voltage. At system level, this solution is therefore not only robust but competitive as well.     

An 8-bit 20-MS/s ZCBC Time-Domain Analog-to-Digital Data Converter

An 8-bit 20-MS/s time-domain analog-to-digital data converter (ADC) using the zero-crossing-based circuit technique is presented. Compared with the conventional ADCs, signal processing is executed in both the voltage and time domains. Since no high-gain operational amplifier is needed, this time-domain ADC works well in a low supply voltage. The proposed ADC has been fabricated in a 0.18-mum CMOS process. Its power dissipation is 4.64 mW from a supply voltage of 1.8 V. This active area occupies 1.2 times 0.7 mm². The measured signal-to-noise-distortion ratio achieves 44.2 dB at an input frequency of 10 MHz. The integral nonlinearity is less than plusmn1.07 LSB, and the differential nonlinearity is less than plusmn0.72 LSB. This time-domain ADC achieves the effective bits of 7.1 for a Nyquist input frequency at 20 MS/s.     

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 10-bit 30-MS/s successive approximation register analog-to-digital converter for low-power sub-sampling applications

A 10-bit 30-MS/s successive approximation register analog-to-digital converter (ADC), which is suitable for low-power sub-sampling applications, is presented. Bootstrapped switches are used to enhance the sampling linearity at the high input frequency. The proposed ADC adopts a binary-weighted split-capacitor array with the energy efficient switching procedure and includes an asynchronous clock scheme to yield more power and speed-efficiency. The ADC is fabricated in a 65 nm complementary metal-oxide-semiconductor technology and occupies an active area of 0.07 mm². The differential and integral nonlinearities of the ADC are less than 0.82 and 1.13 LSB, respectively. The ADC shows a signal-to-noise-distortion ratio of 56.60 dB, a spurious free dynamic range of 73.35 dB, and an effective number of bits (ENOB) of 9.11-bits with a 2.5-MHz sinusoidal input at 30-MS/s. It exhibits higher than 8.86 ENOB for input frequencies up to 78-MHz. The ADC consumes 0.85 mW at a 1.1 V supply and achieves a figure-of-merit of 51 fJ/conversion-step.