Gm-Free Assisted Opamp Technique for Continuous Time Delta-Sigma Modulators

ElShater, Ahmed; Lee, Calvin Y.; Venkatachala, Praveen Kumar; Dessouky, Mohamed; Moon, Un-Ku

doi:10.1109/iscas.2019.8702717

Cited by 3 publications

(2 citation statements)

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“…where τ is given by 1/(2πGBW). Equations ( 3) and (6) show that t slew must be small enough for the integrator to achieve good linearity. Therefore, the OTA needs to stabilize quickly across the slewing.…”

Section: Sr Of Sc Circuitmentioning

confidence: 99%

“…This requirement, that the bandwidth of the OTA must exceed the sampling frequency by several times [ 5 ], poses a significant challenge to the development of low-power DTDSMs. In a typical DTDSM, the operational transconductance amplifier (OTA) is often the module that consumes the most power due to its requirement for a large static bias current [ 6 ]. However, during the sampling phase, this static bias current leads to a significant power loss.…”

Section: Introductionmentioning

confidence: 99%

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A 90.9 dB SNDR 95.3 dB DR Audio Delta–Sigma Modulator with FIA-Assisted OTA

Huang,

Wei,

Wei

2024

Sensors

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This paper presents a low-power, high-gain integrator design that uses a cascode operational transconductance amplifier (OTA) with floating inverter–amplifier (FIA) assistance. Compared to a traditional cascode, the proposed integrator can achieve a gain of 80 dB, while reducing power consumption by 30%. Upon completing the analysis, the value of the FIA drive capacitor and clock scheme for the FIA-assisted OTA were obtained. To enhance the dynamic range (DR) and mitigate quantization noise, a tri-level quantizer was employed. The design of the feedback digital-to-analog converter (DAC) was simplified, as it does not use additional mismatch shaping techniques. A third-order, discrete-time delta–sigma modulator was designed and fabricated in a 0.18 μm complementary metal-oxide semiconductor (CMOS) process. It operated on a 1.8 V supply, consuming 221 µW with a 24 kHz bandwidth. The measured SNDR and DR were 90.9 dB and 95.3 dB, respectively.

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Section: Sr Of Sc Circuitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%