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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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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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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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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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Pan, S. (author), Angevare, J. (author), Makinwa, K.A.A. (author)Resistor-based temperature sensors can achieve higher resolution and energy-efficiency than traditional BJT-based sensors. To reach similar accuracy, however, they typically require 2-point (2-pt) calibration, compared to the low-cost 1-pt calibration required by BJT-based sensors. This paper presents a hybrid temperature sensor that uses an...conference paper 2021
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Jiang, H. (author), Pan, S. (author), Gürleyük, C. (author), Makinwa, K.A.A. (author)Recently, rapid strides have been made in improving the accuracy of RC-based frequency references [1 -3]. Inaccuracies better than \pm 500ppm from -45^{\circ}C to 85^{\circ}C have been achieved, but typically at the expense of a costly and time-consuming 2-point trim to compensate for RC spread and temperature dependence. This paper describes...conference paper 2021
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Someya, T. (author), Van Hoek, Vincent (author), Angevare, J. (author), Pan, S. (author), Makinwa, K.A.A. (author)This paper presents a 210nW BJT-based temperature sensor that achieves an inaccuracy of ±0.15°C (3s) from -15°C to 85°C. A dual-mode front-end (FE), which combines a bias circuit and a BJT core, halves the power needed to generate well-defined CTAT (VBE) and PTAT (?VBE) voltages. The use of a tracking ?S ADC reduces FE signal swing and...conference paper 2022
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Jouvaeian, Amirhossein (author), Fan, Q. (author), Motz, Mario (author), Ausserlechner, Udo (author), Makinwa, K.A.A. (author)Magnetic current sensors are widely used in applications where galvanic isolation and wide bandwidth (BW) are desired, such as in switched-mode power supplies and motor drivers. By using Hall plates for low frequencies and pick-up coils for high frequencies, hybrid magnetic sensors can achieve high resolution (tens of textmA) over a wide...conference paper 2023
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Tang, Z. (author), Pan, S. (author), Makinwa, K.A.A. (author)BJT-based temperature sensors are widely used because they can achieve excellent accuracy after 1-point calibration. However, they typically dissipate mu textWs of power and require supply voltages above 1V [1]. Although sensors based on DTMOSTs [2], [3], capacitively biased (CB) diodes and BJTs [4,5] have demonstrated sub-1V operation, this...conference paper 2023
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Yue, X. (author), Javvaji, L.S. (author), Tang, Z. (author), Makinwa, K.A.A. (author), Du, S. (author)Synchronized bias-flip rectifiers, such as synchronized switch harvesting on inductor (SSHI) rectifiers, are widely used for piezoelectric energy harvesting (PEH) [1], which can replace the use of batteries in many loT applications, thus reducing both system volume and maintenance cost. However, the output power extracted by such rectifiers...conference paper 2023
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Zhang, H. (author), Berkhout, Marco (author), Makinwa, K.A.A. (author), Fan, Q. (author)Class-D amplifiers (CDAs) are widely used in audio applications where a high power efficiency is required. As most audio sources are digital nowadays, implementing digital-input CDAs results in higher levels of integration and lower cost. However, prior open-loop digital-input CDAs suffer from high jitter sensitivity and output-stage...conference paper 2023
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Toth, N.G. (author), Tang, Z. (author), Someya, T. (author), Pan, S. (author), Makinwa, K.A.A. (author)BJT-based temperature sensors are widely used due to their high accuracy over a wide temperature range with a low-cost 1-point trim. Although resistor-based sensors can achieve better energy efficiency, they typically require a 2-point trim to achieve comparable accuracy, while thermal-diffusivity based sensors achieve superior accuracy at...conference paper 2023
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Tang, Z. (author), Toth, N.G. (author), Brito Zamparette, R.L. (author), Nezuka, Tomohiro (author), Furuta, Yoshikazu (author), Makinwa, K.A.A. (author)Low-cost metal (e.g., PCB trace) shunts can be used to make accurate current sensors (< 1 % gain error) [1-3]. However, their reported maximum operating temperature (85 circC) is not high enough for automotive applications, and at higher temperatures, shunt resistance may exhibit increased drift, especially at high current levels. This...conference paper 2023
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An, X. (author), Pan, S. (author), Jiang, H. (author), Makinwa, K.A.A. (author)CMOS frequency references based on RC oscillators are usually preferred over bulky crystals in loT applications [1-5]. However, due to the process spread and finite temperature coefficient (TC) of most on-chip resistors, RC oscillators require trimming and temperature compensation to achieve decent accuracy. Enabled by high-resolution...conference paper 2023
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Rooijers, C.T. (author), Huijsing, J.H. (author), Makinwa, K.A.A. (author)In chopper amplifiers, the interaction between the input signal and the chopper clock can cause intermodulation distortion (IMD). This is due to amplifier delay, which causes signal transitions generated by the input chopper to arrive at the amplifier's output slightly later than the corresponding clock transitions of the output chopper. This...conference paper 2023
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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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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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Javvaji, L.S. (author), Bolatkale, M. (author), Bajoria, Shagun (author), Rutten, Robert (author), Essink, Bert Oude (author), Beijens, Koen (author), Makinwa, K.A.A. (author), Breems, L.J. (author)Advances in CMOS technologies have led to the development of continuous-time ΔΣ modulators (CTDSMs) with GHz sampling rates that achieve better than-100dBc linearity and bandwidths above 100MHz. However, at low frequencies (below 10MHz), their SNDR is limited by 1/f noise, which limits their use in radio receivers intended to cover both the...conference paper 2023
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Brito Zamparette, R.L. (author), Makinwa, K.A.A. (author)This paper presents a nano-power high-side shunt-based current sensor (CS) that digitizes the voltage drop across an on-chip (±1A) or a lead-frame (±30A) shunt. A TC-tunable ADC reference compensates for the shunts' large temperature coefficient (TC), resulting in ±0.5% gain error from -40 to 85°C. The CS employs a capacitively coupled gm...conference paper 2023
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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