Design of a 4th-order multi-stage feedforward operational amplifier for continuous-time bandpass delta sigma modulators

Yang, Xi; Lee, Hae-Seung

doi:10.1109/iscas.2016.7527426

Cited by 11 publications

(11 citation statements)

References 8 publications

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“…To put the results in context, the work is compared with recently reported FF-compensated amplifiers of bandpass Σ∆ modulators in Table II. The amplifiers in [1], [4], [6] were designed to work in Σ∆ modulators at f s = 0.8 GHz, 0.8 GHz and 1 GHz respectively. This work achieves the highest unitygain-frequency at 11 GHz.…”

Section: Results and Comparisonmentioning

confidence: 99%

“…This work achieves the highest unitygain-frequency at 11 GHz. It consumes 13 and 21 mW more than [4] and [6] respectively. However, it improves the gain at 2 GHz by 12 dB compared to [6] and by 17 dB with respect to that of [4].…”

Section: Results and Comparisonmentioning

confidence: 99%

“…would bring the three left-hand zeros to the unity-gainfrequency of the first amplification stage. Other scaling factor choices enable to separate the zeros and position them such that a workable initial design of the 4 th -order op-amp can be obtained [6].…”

Section: System-level Descriptionmentioning

confidence: 99%

“…Sizing of the unit differential pair for a desired pole can be readily carried out under the assumption that it is a single-pole system where the unity-gain-frequency ( f u ) is the product of the dc gain and the pole frequency. The unity-gain-frequency ( f u ∼ g m/C i ) and the pole frequency, p i , is given as in (6) where C i is the sum of the total parasitic capacitances at the output node (C ddn + C dd p + C ggn of the next stage).…”

Section: Design Of the Amplifiermentioning

confidence: 99%

“…Nonetheless, it fails to produce large gain beyond 1 GHz and only reaches a unity-gain-frequency of 3 GHz. The 4 th -order FF-compensated op-amp in [6] fulfills performance requirements of a multi-GHz sampling frequency Σ∆ modulator at the cost of large silicon area.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Design of a 4th-Order Feed-Forward-Compensated Operational Amplifier for Multi-GHz Sampling Frequency Continuous-Time Bandpass Sigma-Delta Modulators

Gebreyohannes¹,

Louërat²,

Aboushady³

2019

2019 IEEE International Symposium on Circuits and Systems (ISCAS)

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This work presents a 4 th-order multi-stage, multipath, feed-forward-compensated operational amplifier in 65 nm CMOS technology. It is designed to meet the requirements of a continuous-time bandpass Σ∆ modulator with multi-GHz sampling frequency. The designed amplifier is modular with each stage implemented based on a unit differential amplifier block and it meets its targets with smart placement of poles and zeros. The amplifier is simulated under the loading condition of a single-amplifier resonator which is in turn part of a 6 thorder Σ∆ modulator. The unloaded amplifier reaches a unitygain-frequency of 38.29 GHz and a DC gain of 58 dB. With a parallel load of 440 fF and 300 Ω, representing the maximum load, the op-amp, including common-mode and biasing circuits, consumes a total of 18.98 mA from a supply voltage of 1.2 V. It is unconditionally stable with a phase margin of 54 • and has gains of 35 dB and 23 dB at 1 GHz and 2 GHz respectively.

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Section: Results and Comparisonmentioning

confidence: 99%