A 12-bit 3.125 MHz Bandwidth 0–3 MASH Delta-Sigma Modulator

We demonstrate a 12-bit 0–3 MASH delta-sigma modulator with a 3.125 MHz bandwidth in a 0.18 $muhbox{m}$ CMOS technology. The modulator has an oversampling ratio of 8 (clock frequency of 50 MHz) and achieves a peak SNDR of 73.9 dB (77.2 $~$dB peak SNR) and consumes 24 mW from a 1.8 V supply. For comparison purposes, the modulator can be re-configured as a single-loop topology where a peak SNDR of 64.5 dB (66.3 dB peak SNR) is obtained with 22 mW power consumption. The energy required per conversion step for the 0–3 MASH architecture (0.95 pJ/step) is less than half of that required by the feedback topology (2.57 pJ/step).      

A 22?mW 512?MHz CMOS continuous time sigma delta ADC in 1.2?V with 16?MHz signal bandwidth and 70?dB dynamic range

A wide bandwidth continuous time sigma delta analog-to-digital conversion is implemented in 130?nm process. The circuit is targeted for wide bandwidth applications such as video or wireless base-stations. The third-order continuous time sigma delta modulator comprises a third-order RC operational-amplifier-based loop filter and 3-bit internal quantizer operated at 512?MHz clock frequency. To reduce the clock jitter sensitivity, nonreturn-to-zero DAC pulse shaping is used. The excess loop delay is set to half the sampling period of the quantizer, and the degradation of modulator stability due to excess loop delay is avoided with this architecture. The sigma delta ADC achieves a 60?dB SNR and a 59.3?dB signal-to-noise-plus-distortion ratio over a 16?MHz signal band at an oversampling ratio of 16. The power consumption of the continuous time sigma delta modulator is 22 mW from the 1.2?V supply.     

A Hybrid Audio ΔΣ Modulator with dB‐Linear Gain Control Function

A hybrid ΔΣ modulator for audio applications is presented in this paper. The pulse generator for digital‐to‐analog converter alleviates the requirement of the external clock jitter and calibrates the coefficient variation due to a process shift and temperature changes. The input resistor network in the first integrator offers a gain control function in a dB‐linear fashion. Also, careful chopper stabilization implementation using return‐to‐zero scheme in the first continuous‐time integrator minimizes both the influence of flicker noise and inflow noise due to chopping. The chip is implemented in a 0.13 μm CMOS technology (I/O devices) and occupies an active area of 0.37 mm². The ΔΣ modulator achieves a dynamic range (A‐weighted) of 97.8 dB and a peak signal‐to‐noise‐plus‐distortion ratio of 90.0 dB over an audio bandwidth of 20 kHz with a 4.4 mW power consumption from 3.3 V. Also, the gain of the modulator is controlled from –9.5 dB to 8.5 dB, and the performance of the modulator is maintained up to 5 ns_RMS external clock jitter.     

10‐Bit 200‐MS/s Current‐Steering DAC Using Data‐Dependant Current‐Cell Clock‐Gating

This letter proposes a low‐power current‐steering digital‐to‐analog converter (DAC). The proposed DAC reduces the clock power by cutting the clock signal to the current‐source cells in which the data will not be changed. The 10‐bit DAC is implemented using a 0.13‐μm CMOS process with V_DD=1.2 V. Its area is 0.21 mm². It consumes 4.46 mW at a 1‐MHz signal frequency and 200‐MHz sampling rate. The clock power is reduced to 30.9% and 36.2% of a conventional DAC at 1.25‐MHz and 10‐MHz signal frequencies, respectively. The measured spurious free dynamic ranges are 72.8 dB and 56.1 dB at 1‐MHz and 50‐MHz signal frequencies, respectively.     

A Power-Efficient Two-Channel Time-Interleaved ΣΔ Modulator for Broadband Applications

A two-channel time-interleaved second-order sigma-delta modulator for broadband applications including asymmetrical digital subscriber line (ADSL) is presented. The proposed two-channel SigmaDelta modulator uses a single integrator channel which does not require additional active elements for the quantizer input generation, since the integrator outputs are directly used as the input of the quantizers. As a result, the entire modulator can be implemented using only two op-amps, which is beneficial for both power consumption and area. Furthermore, this architecture is robust to channel mismatch effects and can operate with a simple clocking scheme. The SigmaDelta modulator achieves a dynamic range of 85 dB over a 1.1-MHz signal bandwidth with an effective clock frequency of 132 MHz. The circuit is implemented in 0.18-mum CMOS technology using metal-insulator-metal capacitors. The total power consumption of the SigmaDelta modulator is 5.4mW from a 1.8-V supply and occupies an active area of 1.1 mm²     

A 14 mW 2.5 MS/s 14 bit Σ∆ Modulator Using Split-Path Pseudo-Differential Amplifiers

This paper presents the design and experimental results of a 1.25 MHz signal bandwidth 14 bit CMOS SigmaDelta modulator. With our proposed switched-capacitor split-path pseudo-differential amplifiers, this modulator achieves high power efficiency, high sampling frequency, and small die area. A new signal and reference front-end sampling network eliminates the input common-mode voltage and reduces power consumption and linearity requirement of the opamp. A prototype chip has been designed and fabricated in a 0.25 mum CMOS technology with a core area of 0.27 mm². Experimental results show that an 84 dB dynamic range is achieved over a 1.25 MHz signal bandwidth when clocked at 125 MHz. The power dissipation is 14 mW at 2.4 V including on-chip voltage reference buffers.     

A low-power and low-complexity continuous-time Gm-C based Delta-Sigma modulator for WCDMA/UMTS

This article describes the implementation of a continuous-time Delta-Sigma modulator for WCDMA/UMTS in wireless communication. The Delta-Sigma modulator employs a Gm-C based integrator to form a fourth-order noise-shaping loop. The modulator samples at 160 MHz and has an over-sampling ratio of 40 in 2 MHz bandwidth. To reduce power consumption and design complexity, single-bit quantisation is employed. The modulator is implemented in 0.25 µm 1-ploy 5-metal CMOS technology and has an area of 0.13 mm². The modulator can achieve 70.7 dB of signal-to-noise-plus-distortion-ratio and 74 dB of dynamic range. Finally, the modulator consumes 3.5 mW of power with a reduced power supply of 1.8 V.     

A 14 Bit Continuous-Time Delta-Sigma A/D Modulator With 2.5 MHz Signal Bandwidth

A continuous-time delta-sigma A/D modulator with 5 MS/s output rate in a 2.5 V 0.25 mum CMOS process is presented. The modulator has a fifth-order single-stage, dual-loop architecture allowing nearly one clock period quantizer delay. A multi-bit quantizer is used to increase resolution and multi-bit non-return-to-zero DACs are adopted to reduce clock jitter sensitivity. Capacitor tuning is utilized to overcome loop coefficient shifts due to process variations. Self-calibration is implemented to suppress current-steering DAC mismatch. Clocked at 60 MHz, the prototype chip achieves 81 dB peak SNR and 85 dB dynamic range with a 12X oversampling ratio. The power consumption is 50 mW.     

Dual-band RF receiver for GPS-L1 and compass-B1 in a 55-nm CMOS

A fully integrated dual-band RF receiver with a low-IF architecture is designed and implemented for GPS-L 1 and Compass-Bl in a 55-nm CMOS process. The receiver incorporates two independent IF channels with 2 or 4 MHz bandwidth to receive dual-band signals around 1.57 GHz respectively. By implementing a flexible frequency plan, the RF front-end and frequency synthesizer are shared for the dual-band operation to save power consumption and chip area, as well as avoiding LO crosstalk. A digital automatic gain control （AGC） loop is utilized to improve the receiver＇s robustness by optimizing the conversion gain of the analog-to-digital converter （ADC）. While drawing about 20 mA per channel from a 1.2 V supply, this RF receiver achieves a minimum noise figure （NF） of about 1.8 dB, an image rejection （IMR） of more than 35 dB, a maximum voltage gain of about 122 dB, a gain dynamic range of 82 dB, and an maximum input-referred 1 dB compression point of about -36.5 dBm with an active die area of 1.5 × 1.4 mm2 for the whole chip.     

A selectable-bandwidth 3.5 mW, 0.03?mm2 self-oscillating Sigma Delta modulator with 71 dB dynamic range at 5?MHz and 65 dB at 10?MHz bandwidth

In this paper we present a dual-mode third-order continuous time $\Upsigma\Updelta$ modulator that combines noise-shaping and pulse-width-modulation (PWM). In our 0.18???m CMOS prototype chip the clock frequency equals 1?GHz, but the PWM carrier is only around 125?MHz. By adjusting the loop filter, the ADC bandwidth can be set to 5 or 10?MHz. In the 5?MHz mode the peak SNDR equals 64?dB and the dynamic range 71?dB. In the 10?MHz mode the peak SNDR equals 58?dB and the DR 65?dB. This performance is achieved at an attractively low silicon area of 0.03?mm² and a power consumption of 3.5?mW.     

A low-power DCO using inverter interlaced cascaded delay cell

This paper presents a low-power small-area digitally controlled oscillator(DCO) using an inverters interlaced cascaded delay cell(IICDC).It uses a coarse-fine architecture with binary-weighted delay stages for the delay range and resolution.The coarse-tuning stage of the DCO uses IICDC,which is power and area efficient with low phase noise,as compared with conventional delay cells.The ADPLL with a DCO is fabricated in the UMC 180-nm CMOS process with an active area of 0.071 mm2.The output frequency range is 140–600 MHz at the power supply of 1.8 V.The power consumption is 2.34 m W @ a 200 MHz output.     

A 13.5-mW 185-Msample/s ΔΣ modulator for UMTS/GSMdual-standard IF reception

A system-oriented approach for the design of a UMTS/GSM dual-standard ΔΣ modulator is presented to demonstrate the feasibility of achieving intermediate frequency (IF) around 100 MHz, high dynamic range, and low power consumption at the same time. The circuit prototype implements 78 MHz IF for GSM and 138.24 MHz for wideband code division multiple access (WCDMA), which are set to be 3/4 of the analog-to-digital converter sampling rate. A two-path IF sampling and mixing topology with a low-pass ΔΣ modulator, run at half the sampling rate, is used. Implemented in 0.25-μm CMOS, the circuit achieves dynamic range and peak signal-to-noise and distortion ratio for GSM of 86 and 72 dB, respectively. The corresponding values for WCDMA are 54 and 52 dB, respectively. Optimization is performed at all stages of design to minimize power consumption. The complete circuit consumes less than 11.5 mW for GSM and 13.5 mW for WCDMA at 2.5-V supply, of which 8 mW is due to the analog part     

A CMOS 0.8-μm transistor-only 1.63-MHz switched-current bandpassΣΔ modulator for AM signal A/D conversion

This paper presents a CMOS 0.8-μm switched-current (SI) fourth-order bandpass ΣΔ modulator (BP-ΣΔM) IC capable of handling signals up to 1.63 MHz with 105-bit resolution and 60-mW power consumption from a 5-V supply voltage. This modulator Is intended for direct A/D conversion of narrow-band signals within the commercial AM band, from 530 kHz to 1.6 MHz. Its architecture is obtained by applying a low-pass-to-bandpass transformation (z^-1 →-z^-2) to a 1-bit second-order low-pass ΣΔ modulator (LP-ΣΔM). The design of basic building blocks is based upon a detailed analysis of the influence of SI errors on the modulator performance, followed by design optimization. Memory-cell errors have been identified as the dominant ones. In order to attenuate these errors, fully differential regulated-folded cascode memory cells are employed. Measurements show a best SNR peak of 65 dB for signals of 10-kHz bandwidth and an intermediate frequency (IF) of 1.63 MHz. A correct noise-shaping filtering is achieved with a sampling frequency of up to 16 MHz     

A UHF current-mode continuous-time band-pass delta sigma modulator using fully balanced active inductor

This paper introduces a 2 GHz continuous-time (CT) fourth order current-mode (CM) band-pass 0.18 μm CMOS delta sigma modulator (DSM) utilizing a fully balanced active inductor. The proposed active inductor takes advantage of positive feedback topology and features accurate loss compensation as well as independent tunability of quality factor and resonant frequency. Based on this active inductor, a CM Ultra High Frequency (UHF) resonator is also proposed, exhibiting a very small on-chip area. Moreover, a high speed CM quantizer working with one single clock is brought into eliminate the error introduced by clock generators. The post layout simulation of the DSM exhibits a peak SNDR of 43.6 dB at 500 MHz with a 40 MHz signal bandwidth while the center frequency can be tuned between 450 and 500 MHz. The measured results give an averaged SNDR of 33 dB with 40 MHz signal bandwidth, where the center frequency is tunable from 300 MHz to 350 MHz. This design consumes only 45 mW under 1.8 V power supply and occupies an area of 0.133 mm².     

一种10 MHz带宽70 dB动态范围连续时间Sigma-Delta调制器

介绍了4阶反馈型连续时间Sigma-Delta调制器从顶层到底层的详细设计过程。采用数字置乱技术,降低失配对输出杂散的影响,使失配产生的谐波被转换为噪声,并被移出通带外。将谐振腔内嵌于调制器环路中,以改善带内信噪比。采用三级前馈型放大器,调制器具备更高的能效。该调制器基于65 nm CMOS工艺设计并流片。测试结果表明,在时钟频率为614.4 MHz、信号带宽为10 MHz时,调制器的SNDR为70.1 dB,动态范围达70 dB。功耗为77 mW。该调制器芯片的内核面积为4.50 mm²。     

A Design-Optimized Continuous-Time Delta–Sigma ADC for WLAN Applications

A third-order continuous-time delta-sigma (DeltaSigma) analog-to-digital converter (ADC) is presented for the conversion of an input signal bandwidth of 10 MHz. Design optimization towards minimal power consumption is demonstrated for the high-speed low-power building blocks of the DeltaSigma modulator. From this point of view, it is shown that GmC integrators are preferred over RC integrators in the low-pass filter of the modulator because they show a better tradeoff between power, speed, and accuracy. A new single-bit quantizer topology is presented that incorporates a local feedback path that improves stability using a switched-voltage technique. Finally, a design methodology for the single-bit digital-to-analog converter (DAC) in the feedback loop is proposed, focusing on the impact of high sampling rates on the stability of the converter. The presented continuous-time ADC achieves a simulated dynamic range of 72 dB and a signal-to-noise-and-distortion-ratio of 66 dB in a 10-MHz signal bandwidth. Therefore, it can be applied for WLAN broadband communication. The power consumption of the DeltaSigma modulator is limited to 7.5 mW. The chip is designed in a 0.18-mum triple-well CMOS technology     

A Wideband ΔΣ Digital-RF Modulator for High Data Rate Transmitters

A wideband software-defined digital-RF modulator targeting Gb/s data rates is presented. The modulator consists of a 2.625-GS/s digital DeltaSigma modulator, a 5.25-GHz direct digital-RF converter, and a fourth-order auto-tuned passive LC RF bandpass filter. The architecture removes high dynamic range analog circuits from the baseband signal path, replacing them with high-speed digital circuits to take advantage of digital CMOS scaling. The integration of the digital-RF converter with an RF bandpass reconstruction filter eliminates spurious signals and noise associated with direct digital-RF conversion. An efficient passgate adder circuit lowers the power consumption of the high-speed digital processing and a quadrature digital-IF approach is employed to reduce LO feedthrough and image spurs. The digital-RF modulator is software programmable to support variable bandwidths, adaptive modulation schemes, and multi-channel operation within a frequency band. A prototype IC built in 0.13-mum CMOS demonstrates a data rate of 1.2 Gb/s using OFDM modulation in a bandwidth of 200 MHz centered at 5.25 GHz. In-band LO and image spurs are less than -59 dBc without requiring calibration. The modulator consumes 187 mW and occupies a die area of 0.72 mm².     

A Wide-Band Phase-Feedback Inverse-Sine Phase Modulator with Application Toward a LINC Amplifier

A wide-band inverse-sine phase modulator is demonstrated. The modulator has application in a LINC amplifier for linear amplification at microwave frequencies using commonly available saturating amplifiers or injection-locked oscillators. A bandwidth greater than 10 MHz at a carrier frequency of 96 MHz with distortion products 40 dB or greater below desired components has been shown. The distortion behavior as a second-order effect of the loop delay as predicted by analysis has been verified. The output of the inverse-sine phase modulator and its conjugate, generated by a second phase modulator, were subtracted as in a LINC amplifier, to provide at least 40-dB suppression of the zeroth order and even-order components.     

A 10–35 GHz Low Power Bulk-DrivenMixer Using 0.13 $mu$m CMOS Process

10-35 GHz doubly balanced mixer using a 0.13-mum CMOS foundry process is presented in this letter. Using the bulk-driven topology, the number of transistors of the doubly balanced mixer is reduced; thus the mixer can achieve a low supply voltage and low power consumption. This bulk-driven mixer exhibits a measured conversion gain of -1 plusmn 2 dB from 10 to 35 GHz of radio frequency (RF) with a fixed intermediate frequency (IF) of 100 MHz. The measured local oscillation (LO) to IF and RF-IF isolations are better than 30 dB. The chip area of the mixer is 0.6 times 0.4 mm². The total power consumption included output buffer is only 6 mW.     

Theory and design of a CT \Updelta\Upsigma modulator with low sensitivity to loop-delay variations

This paper presents a 3rd-order, 3-bit continuous-time (CT) $\Updelta\Upsigma$ Δ Σ modulator for an LTE radio receiver. A return-to-zero (RZ) pulse, centered in the sampling period by a quadrature clock, is used in the innermost DAC to reduce the sensitivity to loop-delay variations in the modulator, and omit implementing the additional loop delay compensation usually needed in CT modulators. The performance and stability of the NRZ/NRZ/RZ feedback scheme is thoroughly analysed using a discrete-time model. The modulator has been implemented in a 65 nm CMOS process, where it occupies an area of 0.2 × 0.4 mm². It achieves an SNR of 71 dB and an SNDR of 69 dB over a 9 MHz bandwidth with an oversampling ratio of 16, and a power consumption of 7.5 mW from a 1.2 V supply.