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Rajaraman, V. (author), Makinwa, K.A.A. (author), French, P.J. (author)We present a simple, flexible and low cost MEMS fabrication process, developed using deep reactive ion etching (DRIE) and wafer bonding technologies, for manufacturing in-plane high aspect ratio (HAR) inertial sensors. Among examples, the design and fabrication results of a two axis inertial device are presented. Fabricated device thickness...conference paper 2008
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Souri, K. (author), Chae, Y. (author), Makinwa, K.A.A. (author)This paper describes an energy-efficient CMOS temperature sensor intended for use in RFID tags. The sensor achieves an inaccuracy of ±0.15°C (3σ) over the military temperature range (-55 to 125°C) and dissipates only 27nJ/conversion: over 20× less than a previous sensor with comparable accuracy and resolution [2]. This energy efficiency is...conference paper 2012
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Pan, S. (author), Jiang, H. (author), Makinwa, K.A.A. (author)This paper presents the most energy-efficient CMOS temperature sensor ever reported, with a resolution FoM of 49fJ·K2, 2.7× better than the state-of-the-art. It consists of a Wheatstone bridge made from poly-silicon resistors, which is readout by a 2nd-order Continuous-Time Delta-Sigma modulator (CTDSM). This approach leads to a high resolution ...conference paper 2017
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Pan, S. (author), Luo, Yanquan (author), Heidary Shalmany, S. (author), Makinwa, K.A.A. (author)Temperature sensors are often used for the temperature compensation of frequency references [1-5]. High resolution and energy efficiency are then critical requirements, the former to minimize jitter and the latter to minimize power dissipation in a given conversion time. A MEMS-resonator-based sensor meets both criteria [1], but requires two...conference paper 2017
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Hussaini, Said (author), Jiang, H. (author), Walsh, Paul (author), MacSweeney, Dermot (author), Makinwa, K.A.A. (author)This paper presents a readout IC that uses an asynchronous charge-redistribution-based capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. Thanks to the power efficient tracking algorithm, the CDC consumes negligible power consumption in the absence of touch events. To facilitate stand-alone or wake-on-touch...conference paper 2018
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Cai, Z. (author), van Veldhoven, Robert (author), Suy, Hilco (author), de Graaf, G. (author), Makinwa, K.A.A. (author), Pertijs, M.A.P. (author)The measurement of carbon-dioxide (CO2) concentration is very important in home and building automation, e.g. to control ventilation in energy-efficient buildings. This application requires compact, low-cost sensors that can measure CO<sub>2</sub> concentration with a resolution of <200 ppm over a 2500ppm range. Conventional optical (NDIR...conference paper 2018
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Rooijers, C.T. (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)The readout of high impedance sensors and sampled voltage references [1]<br/>requires amplifiers with both low offset and low input current. Chopper amplifiers<br/>can achieve low offset, but the switching of their input chopper gives rise to<br/>significant input current (40 to 110pA) [2-4]. Auto-zero (AZ) amplifiers require<br/>less input...conference paper 2018
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Jiang, H. (author), Makinwa, K.A.A. (author)This paper presents an overview of energy-efficient analog-to-digital converters (ADCs) specifically intended for the readout of Wheatstone bridge sensors. Apart from achieving good energy-efficiency, such bridge-to-digital converters (BDCs) must achieve low input-referred offset, drift and noise; high gain accuracy, stability and linearity;...conference paper 2018
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Pan, S. (author), Makinwa, K.A.A. (author)Temperature sensors based on Wheatstone bridges, e.g. [1,2], have recently achieved higher resolution and greater energy efficiency than conventional BJT-based sensors [3]. However, this comes at the expense of area, making them less attractive in industrial applications. This paper presents a Wheatstone-bridge sensor that uses a zoom-ADC...conference paper 2018
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Gürleyük, C. (author), Pedala', L. (author), Sebastiano, F. (author), Makinwa, K.A.A. (author)To comply with wired communication standards such as USB, SATA and PCI/PCI-E, systems-on-chip require frequency references with better than 300ppm accuracy. LC-based references achieve 100ppm accuracy [1], but suffer from high power consumption (∼20mW). Thermal diffusivity (TD) references require less power (∼2mW), at the expense of less...conference paper 2018
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Karmakar, S. (author), Gonen, B. (author), Sebastiano, F. (author), Van Veldhoven, Robert (author), Makinwa, K.A.A. (author)Micro-power ADCs with high linearity and dynamic range (DR) are required in several applications, such as smart sensors, biomedical imaging, and portable instrumentation. Since the signals of interest are then often small (tens of μν) and slow (<1kHz BW), such ADCs should also exhibit low offset and flicker noise. Noise-shaping SAR [1] and...conference paper 2018
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Choi, Woojun (author), Lee, Yong-Tae (author), Kim, Seonhong (author), Lee, Sanghoon (author), Jang, Jieun (author), Chun, Junhyun (author), Makinwa, K.A.A. (author), Chae, Youngcheol (author)In microprocessors and DRAMs, on-chip temperature sensors are essential components, ensuring reliability by monitoring thermal gradients and hot spots. Such sensors must be as small as possible, since multiple sensors are required for dense thermal monitoring. However, conventional BJT-based temperature sensors are not compatible with the sub...conference paper 2018
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Xu, L. (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)This paper presents a fully integrated ±4A current sensor that supports a 25V input common-mode voltage range (CMVR) while operating from a single 1.5V supply. It consists of an on-chip metal shunt, a beyond-the-rails ADC [1] and a temperature-dependent voltage reference. The beyond-the-rails ADC facilitates high-side current sensing without...conference paper 2018
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Angevare, J. (author), Makinwa, K.A.A. (author)A resistor-based temperature sensor has been realized in 180 nm CMOS for SoC thermal management applications. Occupying only 6800 μm<sup>2</sup>, it is the smallest resistor-based temperature sensor ever reported. This is achieved by employing a compact highly-digital VCO-based ADC. After a 2-point trim, the sensor achieves an inaccuracy of ...conference paper 2018
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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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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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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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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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Rooijers, C.T. (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)The readout of high-impedance sensors and sampled voltage references [1] requires amplifiers that can achieve both low offset and low input current. Recently, it has been shown that this unique combination can be achieved by an auto-zero (AZ) stabilized buffer [2]. However, its low-frequency noise density is surd 5 times higher than the...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