Analysis and Design of Low-Power Continuous-Time Delta-Sigma Modulator Using Negative-R Assisted Integrator

Jang, MoonHyung; Lee, Changuk; Chae, Youngcheol

doi:10.1109/jssc.2018.2871111

Cited by 43 publications

(19 citation statements)

References 18 publications

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“…In this topology, the degeneration resistor and the current source allows enhancing the accuracy of matching the circuit within 10%. Moreover, a stable gm of the negative-R is maintained over the temperature and power supply variations [26].…”

Section: Cmos Amplifier Implementationmentioning

confidence: 99%

“…In this paper, we present a high-linear chopper negative-R stabilization audio preamplifier, which employs two proposed techniques to reduce the 1/f noise and the thermal noise at the same time. The two proposed techniques are the delay-time chopper stabilization (CHS) technique [24,25] and the negative-R technique [26]. The paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

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A 5-nV/√Hz Chopper Negative-R Stabilization Preamplifier for Audio Applications

2020

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This paper presents a low-noise and low-power audio preamplifier. The proposed low-noise preamplifier employs a delay-time chopper stabilization (CHS) technique and a negative-R circuit, both in the auxiliary amplifier to cancel the non-idealities of the main amplifier. The proposed technique makes it possible to mitigate the preamplifier 1/f noise and thermal noise and improve its linearity. The low-noise preamplifier is implemented in 65 nm complementary metal-oxide semiconductor (CMOS) technology. The supply voltage is 1.2 V, while the power consumption is 159 µW, and the core area is 192 µm2. The proposed circuit of the preamplifier was fabricated and measured. From the measurement results over a signal bandwidth of 20 kHz, it achieves a signal-to-noise ratio (SNR) of 80 dB, an equivalent-input referred noise of 5 nV/√Hz and a noise efficiency factor (NEF) of 1.9 within the frequency range from 1 Hz to 20 kHz.

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Section: Cmos Amplifier Implementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A 5-nV/√Hz Chopper Negative-R Stabilization Preamplifier for Audio Applications

2020

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“…Anyway, even considering the digital-assisted architectures, the CT integrator is still the bottleneck at increasing the performance of a modulator. Previous works show that it is possible to compensate for the OTA limited DC gain by introducing negative feedback in the integrator [10]- [13]. This solution is sometimes indicated as negative-R assisted integrator.…”

Section: Introductionmentioning

confidence: 99%

“…This solution is sometimes indicated as negative-R assisted integrator. More recent works [11], [13] suggest advantages in implementing this feedback by using a transconductance amplifier. The main contribution of this work concerns implementation considerations for the transconductance based compensation of the limited DC OTA gain.…”

Section: Introductionmentioning

confidence: 99%

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A 65nm Continuous-Time Sigma-Delta Modulator With Limited OTA DC Gain Compensation

González-Díaz

Pareschi

2020

IEEE Access

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This paper explores the effects of compensating the performance degradation in high-speed Continuous-Time Sigma-Delta modulators when the loop integrators are implemented through limited gain Operational Transconductance Amplifiers. Yet, the low DC-gain strongly affects both integrator magnitude and phase responses, with a reduction in the overall effective number of bits. This work models the degradation as due to a signal-dependent memory-less perturbation and theoretically studies its compensation by feeding an opposite signal back to the integrator input. The implementation and experimental results on a 65nm CMOS 2nd order prototype evaluate the performance increase with this technique, where no other compensation, nor any digital calibration, is included. Tested in different conditions, the compensated prototype improves more than 1.5 bit the ENoB with respect to the uncompensated counterpart. For a sampling frequency of 500 MHz the power consumption is 1.7mW, resulting in a 477.2fJ/conv-lev Walden and a 148.8dB Schreirer Figures of Merit.

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