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Angevare, J. (author), Chae, Youngcheol (author), Makinwa, K.A.A. (author)Microprocessors and SoCs employ multiple temperature sensors to prevent overheating and ensure reliable operation. Such sensors should be small (<10,000μm2) to monitor local hot-spots in dense layouts. They should also be moderately accurate (1°C) up to high temperatures (≥125°C), so that the system throttling temperature can be set as...conference paper 2021
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Rooijers, C.T. (author), Karmakar, S. (author), Kusuda, Yoshinori (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)Amplifiers often employ chopping to achieve low offset and low-frequency noise. However, the interaction between the input signal and the chopper clock can cause chopper-induced intermodulation distortion (IMD) [1] -[5]. This is especially problematic for input frequencies (Fin) near even multiples of the chopping frequency (FCH), as the...conference paper 2021
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Campos de Oliveira, A. (author), Groenesteijn, Jarno (author), Wiegerink, Remco J. (author), Makinwa, K.A.A. (author)Precision flow sensors are widely used in the pharmaceutical, food, and semiconductor industries to measure small amounts (<1 gram/hour) of liquids and gases. MEMS thermal flow sensors currently achieve state-of-the-art performance in terms of resolution, size, and power consumption [1, 3]. However, they only measure volumetric flow, and...conference paper 2021
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Choi, Woojun (author), Angevare, J. (author), Park, Injun (author), Makinwa, K.A.A. (author), Chae, Youngcheol (author)Wireless sensor nodes in battery-powered internet-of-things (loT) applications require a stable on-chip frequency reference with low energy (<10 pJ / cycle) and high frequency stability (below ±300ppm). CMOS RC frequency references are promising due to their low-cost integration and high energy efficiency [1] –[5]. Conventional RC references,...conference paper 2021
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Jouyaeian, A. (author), Fan, Q. (author), Motz, Mario (author), Ausserlechner, Udo (author), Makinwa, K.A.A. (author)Magnetic current sensors are used in switched-mode power supplies and motor drivers, where both galvanic isolation and wide bandwidth (BW) are desired. In CMOS, Hall-effect sensors are widely used, but their resistance results in a fundamental trade-off between BW and resolution. Coils have a differentiating characteristic and so can achieve...conference paper 2021
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Zhang, H. (author), Berkhout, M. (author), Makinwa, K.A.A. (author), Fan, Q. (author)This paper reports a Class-D audio amplifier that uses multiloop feedback to suppress output LC filter nonlinearity by 49 dB, enabling the use of small, low-cost LC filters with ±30% spread while maintaining low distortion. Fabricated in a 180 nm BCD process, the prototype achieves a THD of-121.5 dB and a THD+N of-107.1 dB. It delivers 12W...conference paper 2021
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Aydin, E. (author), Makinwa, K.A.A. (author)This paper presents a portable and contactless microfluidic flowmeter based on the Nuclear Magnetic Resonance (NMR) principle, which can measure flow rates up to 2.7 ml/min with \pm 16\ lmin (±0.6% full-scale) error. It consists of a millimeter-size RF coil wound around a microfluidic channel, custom readout electronics and a 0.5 T permanent...conference paper 2021
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Eland, E.N. (author), Karmakar, S. (author), Gonen, B. (author), Veldhoven, R. van (author), Makinwa, K.A.A. (author)This paper presents a discrete-time (DT) zoom ADC for audio applications. A 2b quantizer in combination with a low power “fuzz” suppression technique, results in a significant improvement in linearity and energy-efficiency over previous designs. The ADC occupies 0.27mm 2 in 0.16μm CMOS and consumes 440μW from a 1.8V supply. In a 20kHz BW, it...conference paper 2020
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Pan, S. (author), Makinwa, K.A.A. (author)Energy efficiency and accuracy are important specifications of CMOS temperature sensors. BJT -based sensors achieve state-of-the-art accuracy [1], while Wheatstone-bridge (WhB) sensors achieve lower accuracy but state-of-the-art energy efficiency [2], [3]. This paper presents a WhB sensor that is read out by an energy-efficient continuous...conference paper 2020
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Gürleyük, C. (author), Pan, S. (author), Makinwa, K.A.A. (author)Systems-on-chip traditionally rely on bulky quartz crystals to comply with wired communication standards like CAN or USB 2.0. Integrated frequency references with better than 500ppm inaccuracy could meet this need, resulting in higher integration and lower cost. Candidate architectures have employed RC-, LC- or TD (thermal diffusivity)-based...conference paper 2020
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Pimenta, Matheus (author), Gürleyük, C. (author), Walsh, Paul (author), O’Keeffe, Daniel (author), Babaie, M. (author), Makinwa, K.A.A. (author)This paper describes a low-power eddy current displacement sensor intended for safety-critical touch applications. A sensing inductor is incorporated into a digital PLL to efficiently digitize the displacement of a flexible metal foil. At a stand-off distance of 500μm, the sensor achieves 6.7nm resolution in a 3kHz bandwidth over a 43μm range...conference paper 2020
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Zhang, H. (author), Karmakar, S. (author), Breems, Lucien (author), Sandifort, Quino (author), Berkhout, M. (author), Makinwa, K.A.A. (author), Fan, Q. (author)This paper describes a class-D audio amplifier with a multilevel output stage that reduces both EMI and idle power. High loop gain, and thus high linearity, are enabled by a relatively high (4.2 MHz) switching frequency, which relaxes the requirements on its output LC filter. Fabricated in a 180nm BCD technology, it can drive 14 W into an 8-Ω...conference paper 2020
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Karmakar, S. (author), Zhang, H. (author), Van Veldhoven, Robert (author), Breems, Lucien (author), Berkhout, M. (author), Fan, Q. (author), Makinwa, K.A.A. (author)Class-D amplifiers are often used in high-power audio applications due to their high power efficiency. They typically employ pulse-width modulation (PWM) at a fixed carrier frequency, which may cause electromagnetic interference (EMI). Setting this frequency f<sub>PWM</sub>) below the AM band (535 to 1605kHz) helps mitigate this, but its...conference paper 2020
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Lee, Yongtae (author), Choi, Woojun (author), Kim, Taewoong (author), Song, Seungwoo (author), Makinwa, K.A.A. (author), Chae, Youngcheol (author)This letter describes a compact resistor-based temperature sensor intended for the thermal monitoring of microprocessors and DRAMs. It consists of an RC poly phase filter (PPF) that is read out by a frequency-locked loop (FLL) based on a dual zero-crossing (ZC) detection scheme. The sensor,fabricated in 65-nm CMOS,occupies 5800 μm<sup>2</sup>...conference paper 2019
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Pan, S. (author), Makinwa, K.A.A. (author)Temperature sensors intended for embedded applications should be both energy-and area-efficient. The combination of Wheatstone-bridge (WhB) sensors and continuous-time ADCs has proven to be highly energy efficient [1], [2]. However, their area (> 0.25 mm{2}) is still larger than that of comparable BJT-based sensors [3], [4]. This paper...conference paper 2019
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Gonen, B. (author), Karmakar, Shoubhik (author), Veldhoven, Robert Van (author), Makinwa, K.A.A. (author)This paper presents a continuous-time (CT) zoom ADC for use in audio applications. Compared to previous zoom ADCs, its input impedance is mainly resistive, making it much easier to drive while still maintaining high energy efficiency. The prototype is fabricated in a 0.16 ×m CMOS process, occupies 0.27 m m<sup>2</sup> and achieves 108.5 dB DR...conference paper 2019
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Oliveira Alves, A.C. (author), Schut, T. V.P. (author), Groenesteijn, J. (author), Fan, Q. (author), Wiegerink, R. J. (author), Makinwa, K.A.A. (author)This paper describes an interface circuit for a MEMS Coriolis mass flow sensor that combines both drive and sense circuitry. The MEMS sensor consists of a suspended resonant tube, which is read-out by comb capacitors and driven into oscillation by current flowing through a drive coil in a magnet field. The interface circuit comprises a low...conference paper 2019
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Cenci, P. (author), Bolatkale, M. (author), Rutten, R. (author), Ganzerli, M. (author), Lassche, G. (author), Makinwa, K.A.A. (author), Breems, Lucien (author)This paper presents a SAR-assisted Continuous-time Delta-Sigma (CT Δ Σ ) ADC, which combines the energy efficiency of SAR ADCs with the relaxed driving requirements of CT Δ Σ ADCs, as well as similar anti-alias filtering. When clocked at 2.4GHz, the ADC achieves 77.5dB SNDR in 40MHz BW. It consumes 3.2mW, resulting in a state-of-the-art...conference paper 2019
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Rooijers, C.T. (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)This paper presents an input-current trimming scheme for auto-zero amplifiers. Since their input current is mainly due to charge injection,the scheme operates by trimming the clock swing,and hence the charge injection,of two dummy input switches. At room temperature,the trimming scheme reduces the maximum input current of an auto-zero...conference paper 2019
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Pan, S. (author), Gürleyük, C. (author), Pimenta, Matheus F. (author), Makinwa, K.A.A. (author)Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm <sup>2</sup> ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm <sup>2</sup> resistor-based sensor that uses a...conference paper 2019