A Programmable 0.8-V 10-bit 60-MS/s 19.2-mW 0.13-$mu$ m CMOS ADC Operating Down to 0.5 V

This work describes a programmable 10- to 100-MS/s, low-power 10-bit two-step pipeline analog-digital converter (ADC) operating at a power supply from 0.5- to 1.2-V. MOS transistors with a low-threshold voltage are employed partially in the input sampling switches and differential pair of the SHA and MDAC for a proper signal swing margin at a 0.5-V supply. The integrated adjustable current reference optimizes the static and dynamic performance of amplifiers at 10-bit accuracy with a wide range of supply voltages. A signal-isolated layout improves the capacitor mismatch of the multiplying digital-to-analog converter, while a switched- bias power-reduction technique reduces the power dissipation of comparators in the flash ADCs. The prototype ADC in a 0.13-mum CMOS process demonstrates the measured differential nonlin- earity and integral nonlinearity within 0.35 and 0.49 least significant bits. The ADC, with an active die area of 0.98 mm², shows a maximum signal-to-noise distortion ratio and spurious free dynamic range of 56.0 and 69.6 dB, respectively, and a power consumption of 19.2 mW at a nominal condition of 0.8 V and 60 MS/s.     

A 70-MS/s 110-mW 8-b CMOS folding and interpolating A/D converter

A CMOS analog to digital converter based on the folding and interpolating technique is presented. This technique is successfully applied in bipolar A/D converters and now also becomes available in CMOS technology. The analog bandwidth of the A/D converter is increased by using a transresistance amplifier at the outputs of the folding amplifiers and, due to careful circuit design, the comparators need no offset compensation. The result is a small area (0.7 mm² in 0.8 μm CMOS), high speed (70 MS/s), and low-power (110 mW at 5 V supply, including reference ladder) A/D converter. A 3.3 V supply version of the circuit runs at 45 MS/s and dissipates 45 mW     

CMOS图像传感器中RSD A/D转换器的设计与实现

提出了CMOS图像传感器中RSD A/D转换器的设计方法.基于冗余符号数(RSD)算法,RSD A/D转换器降低了对比较器的性能要求.并且全差分的模拟信号处理用以改进抗噪声度,信噪比和系统的动态范围.RSD A/D转换器是基于90 nm CMOS工艺实现的,测试结果表明它的微分非线性误差(DNL)为±1 LSB,积分非线性误差(INL)为±1.5 LSB,总的未调整误差(TUE)为-3 LSB～1 LSB,功耗约为20 mW.     

A CMOS 6-b, 400-MSample/s ADC with error correction

A CMOS 6-bit 400-MSample/s (MS/s) flash analog/digital converter (ADC) using an additional comparator for background autozeroing has been developed. Additionally, an error-correction technique detects and corrects errors after thermometer code zero-to-one transition detection, improving the error rate from 10E-4 to 10E-8 at 400 MS/s with a 200-MHz analog input. This ADC was fabricated in a single-poly, double-metal, 0.35-μm CMOS technology and occupies 1.6×0.75 mm. The power consumption is 190 mW at 400 MS/s with 3.0 V power supply. This ADC has a two-clock cycle latency     

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 10 b, 20 Msample/s, 35 mW pipeline A/D converter

This paper describes a 10 b, 20 Msample/s pipeline A/D converter implemented in 1.2 μm CMOS technology which achieves a power dissipation of 35 mW at full speed operation. Circuit techniques used to achieve this level of power dissipation include digital correction to allow the use of dynamic comparators, and optimum scaling of capacitor values through the pipeline. Also, to be compatible with low voltage mixed-signal system environments, a switched capacitor (SC) circuit in each pipeline stage is implemented and operated at 3.3 V with a new high-speed, low-voltage operational amplifier and charge pump circuits. Measured performance includes 0.6 LSB of INL, 59.1 dB of SNDR (Signal-to-Noise-plus-Distortion-Ratio) for 100 kHz input at 20 Msample/s. At Nyquist sampling (10 MHz input) SNDR is 55.0 dB. Differential input range is ±1 V, and measured input referred RMS noise is 220 μV. The power dissipation at 1 MS/s is below 3 mW with 58 dB of SNDR     

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     

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 1.2?V 10-bit 60-MS/s 23?mW CMOS pipeline ADC with 0.67?pJ/conversion-step and on-chip reference voltages generator

A 1.2?V 10-bit 60?MS/s pipeline Analog-to-Digital Converter (ADC), fabricated in a 130?nm CMOS technology, is presented. The prototype is composed by five 3-bit pipeline stages and a Sample and Hold (S&H) circuit at the front. Two-stage Miller-compensated Operational Transconductance Amplifiers (OTAs), offset-compensated comparators and bootstrapping sampling switches have been used due to the low voltage supply requirements. Special attention has been paid to the reduction of the power consumption using a thorough design methodology. The converter only consumes 23?mW including on-chip reference voltages and bias current generators. The differential and integral nonlinearity of the ADC are below 0.60 and 0.61 LSBs, respectively. The pipeline converter achieves an effective resolution above 9 bits along the Nyquist bandwidth, and obtains 0.67?pJ energy consumption per conversion, making it one of the most energy-efficient 10-bit video-rate pipeline ADC reported to date.     

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.     

An 8/10 bit 200/100MS/s configurable asynchronous SAR ADC

This paper presents an asynchronous 8/10 bit configurable successive approximation register analog-to-digital converter (ADC). The proposed ADC has two resolution modes and can work at a maximal sampling rate of 200 and 100MS/s for 8 bit mode and 10 bit mode respectively. The ADC uses a custom-designed 1 fF unit capacitor to reduce the power consumption and settling time of capacitive DAC, a dynamic comparator with tail current to minimize kickback noise and improve linearity. Moreover, asynchronous control technique is utilized to implement the ADC in a flexible and energy-efficient way. The proposed ADC is designed in 90 nm CMOS technology. At 100MS/s and 1.0 V supply, the ADC consumes 1.06 mW and offers an ENOB of 9.56 bit for 10 bit mode. When the ADC operates at 8 bit mode, the sampling rate is 200MS/s with 1.56 mW power consumption from 1.0 supply. The resulted ENOB is 7.84 bit. The FOMs for 10 bit mode at 100MS/s and 8 bit mode at 200MS/s are 14 and 34 fJ/conversion-step respectively.     

An 8-MHz CMOS subranging 8-bit A/D converter

A 8-bit subranging converter (ADC) has been realized in a 3-/spl mu/m silicon gate, double-polysilicon capacitor CMOS process. The ADC uses 31 comparators and is capable of conversion rates to 8 MHz at V/SUB DD/=5 V. Die size is 3.2/spl times/2.2 mm/SUP 2/.     

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.     

Linear relationship ADC with complimentary switch-based bootstrapped sample and hold circuit

This paper presents the design, fabrication and tested results of an analogue-to-digital converter (ADC) using linear relationship ratio of comparator and resolution. An original N-bit flash architecture uses 2^N?1 comparators (N = resolution), while the proposed architecture uses only N comparators for N-bit making it a linear relationship design. This paper also deals with the design of sample and hold circuit that utilises clock bootstrapping technique which allows sampling at peak voltages and helps in minimising charge injection errors, attaining 125 µV for the proposed design. The proof of concept of 4-bit prototype ADC using 1P?2M is fabricated using AMIS 500 nm CMOS C5X technology and the experimental results at a sampling rate of 800 MS/s reveal an effective no. of bit of 3.34 bits, signal-to-noise ratio of 24.44 dB and differential non-linearity and integral non-linearity of 0.42 and 0.40, respectively. The converter consumes 7 mW power when operated on 2.5 V supply and occupies 0.014 mm² chip area.     

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.     

Calibration-free 14b 70MS/s 0.13 /spl mu/m CMOS pipeline A/D converters based on highmatching 3D symmetric capacitors

A 14b 70MS/s pipeline A/D converter (ADC) in a 0.13 mum CMOS process employs signal insensitive 3D fully symmetric capacitors for high matching accuracy without any calibration scheme. The prototype ADC with a die area of 3.3 mm² shows measured differential and integral nonlinearities of 0.65LSB and 1.80LSB, respectively, at 14b     

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.     

A variability tolerant system-on-chip ready nano-CMOS analogue-to-digital converter

As integrated circuit technologies progress to nanoscale, process variations become relatively large and significantly impact circuit performance. The proactive management of process variation during the design process is critical to ensure effective device yield and to keep manufacturing costs down. In the present scenario, designers are searching for analogue-to-digital converter (ADC) architectures which are nanoscale CMOS processes tolerant. Expectations of the performance of ADCs are continuously increasing along with the progress of digital systems. A process and supply variation tolerant, System-on-Chip (SoC) ready, 1 GS/s, 6-bit flash ADC suitable for integration into nanoscale digital CMOS technologies is presented. The physical design of the ADC has been done using a generic 90 nm Salicide 1.2 V/2.5 V 1 Poly 9 Metal process design kit. Baseline post layout simulation results at nominal supply and threshold voltages are presented. The parasitic-extracted physical design of the ADC is then subjected to a corner-based methodology of process variation. The results show that process variation causes a maximum variation of 10.5% in the integral non-linearity (INL) and 5.7% in the differential non-linearity (DNL), with both INL and DNL being less than 0.5 LSB. The 90 nm ADC consumes a peak power of 5.794 mW and an average power of 3.875 mW. The comparators for the ADC have been designed using the threshold inverting technique. To show technology scalability of the design, the ADC has also been presented using a 45 nm Predictive Technology Models (PTM). At 45 nm, INL = 0.46 LSB, DNL = 0.7 LSB and a sampling rate of 100 MS/s were obtained. The 45 nm ADC consumes a peak power of 45.42 μW, and average power of 8.8 μW.     

A 2.2 mW 1.75 GS/s 5 Bit Folding Flash ADC in 90 nm Digital CMOS

A 5 bit 1.75 GS/s ADC using a factor 2 dynamic folding technique is presented. The 2X folding lowers the number of comparators from 31 to 16, simplifies encoding and reduces power consumption and area. The comparators in this converter are implemented with built-in references and calibration to further reduce power consumption. INL and DNL after calibration are smaller than 0.3 LSB, with an SNDR of 29.9 dB at low frequencies, and above 27.5 dB up to the Nyquist frequency. The converter consumes 2.2 mW from a 1 V supply, yielding a FoM of 50 fJ per conversion step and occupies 0.02 ${hbox{mm}}^{2}$ in a 90 nm 1P9M digital CMOS process.      

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