A 1.95 V, 0.34 mW 12-bit sigma-delta modulator stabilized by local feedback loops

Sigma Delta modulator is widely used in ADC for kinds of micro inertial sensors, Sigma Delta ADC can be easily integrated with digital circuits. It possesses some performances of good linearity and high accuracy, while it has no such strict requirements for the match of device dimensions. In this paper, the design of third-order Sigma Delta modulator with a structure of single-loop full feed-forward is accomplished, meanwhile it uses local feedback for zero optimization to improve the shaping capacity of the modulator noise within the signal bandwidth. The OSR (over-sampling rate) of the modulator is 128 and the signal bandwidth is 10 kHz. By the system model building and simulation in the Simulink of MATALAB, the SNR is 96.3 dB and the ENOB is 15.71 bits. Then the modulator is implemented into transistor-level circuits with 0.5um process, by the simulation in Spectre of Cadence, the SNR is 88.5 dB and the ENOB is 14.41 bits. 搜

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Low noise vacuum MEMS closed-loop accelerometer using sixth-order multi-feedback loops and local resonator sigma delta modulator

2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS) ◽

10.1109/memsys.2014.6765752 ◽

2014 ◽

Cited By ~ 14

Author(s):

Fang Chen ◽

Weizheng Yuan ◽

Honglong Chang ◽

Ioannis Zeimpekis ◽

Michael Kraft

Keyword(s):

Closed Loop ◽

Low Noise ◽

Feedback Loops ◽

Sixth Order ◽

Sigma Delta Modulator ◽

Sigma Delta

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A Feed-Forward Sigma-Delta Modulator Applied in Silicon Gyroscope

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.645-646.657 ◽

2015 ◽

Vol 645-646 ◽

pp. 657-661

Author(s):

Qi Shao ◽

Qiu Ye Lv ◽

Hao Meng ◽

Qiang Fu ◽

Xiao Wei Liu

Keyword(s):

Sampling Rate ◽

Ideal Model ◽

Sigma Delta Modulator ◽

Sigma Delta ◽

Feed Forward ◽

Single Loop ◽

Local Feedback ◽

Signal Band

Aiming to be applied in silicon gyroscope, a three-order single loop feedforward modulator with three-bit quantizer and local feedback is designed in this paper. Signal band is 200 KHz, sampling rate is 25.6 MHz, OSR is 64. Ideal modulator is then designed and simulated in MATLAB, getting SNR 125dB. Non-ideal factors are also added to ideal model, DWA technology is adopted to restrain the nonlinearity of multi-bit quantizer, getting SNR 104dB. Finally, transistor-level full-difference modulator is designed and simulated in Cadence, fetting SNR 101.3dB.

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