This paper presents a 10-bit 100-MSample/s analog-to-digital（A/D） converter with pipelined folding architecture.The linearity is improved by using an offset cancellation technique and a resistive averaging interpolation network.Cascading alleviates the wide bandwidth requirement of the folding amplifier and distributed interstage track/hold amplifiers are used to realize the pipeline technique for obtaining high resolution.In SMIC 0.18μm CMOS,the A/D converter is measured as follows:the peak integral nonlinearity and differential nonlinearity are±0.48 LSB and±0.33 LSB,respectively.Input range is 1.0 VP-P with a 2.29 mm2 active area.At 20 MHz input @ 100 MHz sample clock,9.59 effective number of bits,59.5 dB of the signal-to-noise-and-distortion ratio and 82.49 dB of the spurious-free dynamic range are achieved.The dissipation power is only 95 mW with a 1.8 V power supply.
As the feature size of the CMOS integrated circuit continues to shrink,process variations have become a key factor affecting the interconnect performance.Based on the equivalent Elmore model and the use of the polynomial chaos theory and the Galerkin method,we propose a linear statistical RCL interconnect delay model,taking into account process variations by successive application of the linear approximation method.Based on a variety of nano-CMOS process parameters,HSPICE simulation results show that the maximum error of the proposed model is less than 3.5%.The proposed model is simple,of high precision,and can be used in the analysis and design of nanometer integrated circuit interconnect systems.
A 19 mW highly integrated GPS receiver with a ΣΔ fractional-N synthesizer is presented in this paper.Fractional-N frequency synthesizer architecture was adopted in this work, to provide more degrees of freedom in the synthesizer design.A high linearity low noise amplifier(LNA) is integrated into the chip.The radio receiver chip was fabricated in a 0.18 μm complementary metal oxide semiconductor(CMOS) process and packaged in a 48-pin 2 mm×2 mm land grid array chip scale package.The chip consumes 19 mW(LNA1 excluded) and the LNA1 6.3 mW.Measured performances are:noise figure<2 dB, channel gain=108 dB(LNA1 included), image rejection>36 dB, and-108 dBc/Hz @ 1 MHz phase noise offset from the carrier.The carrier noise ratio(C/N) can reach 41 dB at an input power of-130 dBm.The chip operates over a temperature range of-40, 120 °C and ±5% tolerance over the CMOS technology process.
Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits.Based on the RLC interconnect delay model,by wire sizing,wire spacing and adopting low-swing interconnect technology,this paper proposed a power-area optimization model considering delay and bandwidth constraints simultaneously.The optimized model is verified based on 65-nm and 90-nm complementary metal-oxide semiconductor(CMOS) interconnect parameters.The verified results show that averages of 36% of interconnect power and 26% of repeater area can be saved under 65-nm CMOS process.The proposed model is especially suitable for the computer-aided design of nanometer scale systems-on-chip.
A clock generator circuit for a high-speed high-resolution pipelined A/D converter is presented.The circuit is realized by a delay locked loop(DLL),and a new differential structure is used to improve the precision of the charge pump.Meanwhile,a dynamic logic phase detector and a three transistor NAND logic circuit are proposed to reduce the output jitter by improving the steepness of the clock transition.The proposed circuit,designed by SM1C 0.18μm 3.3 V CMOS technology,is used as a clock generator for a 14 bit 100 MS/s pipelined ADC.The simulation results have shown that the duty cycle ranged from 10%to 90%and can be adjusted.The average duty cycle error is less than 1%.The lock-time is only 13 clock cycles.The active area is 0.05 mm2 and power consumption is less than 15 mW.
An offset cancellation technique for a SAR(successive approximation register) ADC switched-capacitor comparator is described.The comparator is designed with a pre-amplifying and regenerative latching structure and realized in 0.18μm CMOS.With the first stage preamplifier offset cancellation and low offset regenerative latching approach,the equivalent offset of the comparator is reduced to < 0.55 mV.By using the pre-amplifying and regenerative latching comparison mode the comparator exhibits low power dissipation.Under a 1.8 V power supply,with a 200 kS/s ADC sampling rate and 3 MHz clock frequency,a 13-bit comparison resolution is reached and less than 0.09 mW power dissipation is consumed.The superiority of this comparator is discussed and proved by the post-simulation and application to a 10 bit 200 kS/s touch screen SAR A/D converter.
A new design technique for merging the front-end sample-and-hold amplifier(SHA) into the first multiplying digital-to-analog converter(MDAC) is presented.For reducing the aperture error in the first stage of the pipelined ADC,a symmetrical structure is used in a flash ADC and MDAC.Furthermore,a variable resistor tuning network is placed at the flash input to compensate for different cutoff frequencies of the input impedances of the flash and MDAC.The circuit also has a clear clock phase in the MDAC and separate sampling capacitors in the flash ADC to eliminate the nonlinear charge kickback to the input signal.The proposed circuit,designed using ASMC 0.35-μm BiCMOS technology,occupies an area of 1.4 x 9 mm^2 and is used as the front-end stage in a 14-bit 125-MS/s pipelined ADC.After the trim circuit is enabled,the measured signal-to-noise ratio is improved from 71.5 to 73.6 dB and the spurious free dynamic range is improved from 80.5 to 83.1 dB with a 30.8 MHz input. The maximum input frequency is up to 150 MHz without steep performance degradations.
According to the thermal profile of actual multilevel interconnects,in this paper we propose a temperature distribution model of multilevel interconnects and derive an analytical crosstalk model for the distributed resistance-inductance-capacitance (RLC) interconnect considering effect of thermal profile.According to the 65-nm complementary metal-oxide semiconductor (CMOS) process,we compare the proposed RLC analytical crosstalk model with the Hspice simulation results for different interconnect coupling conditions and the absolute error is within 6.5%.The computed results of the proposed analytical crosstalk model show that RCL crosstalk decreases with the increase of current density and increases with the increase of insulator thickness.This analytical crosstalk model can be applied to the electronic design automation (EDA) and the design optimization for nanometer CMOS integrated circuits.
