Low-cost temperature sensors in CMOS technology

Temperature greatly affects the performance of integrated circuits, and so temperature sensors are often necessary to ensure reliable operation and stable performance. The goal of the work described in this thesis is to realize a temperature sensor in CMOS technology that can be produced at low cost. In the first step, a temperature sensor is...

A Compact Sub-1V Capacitively-Biased BJT-Based Temperature Sensor

This thesis presents the design of a low-power, sub-1V, BJT-based temperature sensor. It is based on a capacitively-biased (CB) BJT front-end, in which capacitors are discharged across diode-connected BJTs to obtain proportional-to-temperature (PTAT) and complementary-to-temperature (CTAT) voltages. These voltages are then digitised by a...

A Sub-1 V Capacitively Biased BJT-Based Temperature Sensor With an Inaccuracy of ± 0.15 ∘ C (3 σ ) From − 55 ∘ C to 125 ∘ C

This article presents a sub-1 V bipolar junction transistor (BJT)-based temperature sensor that achieves both high accuracy and high energy efficiency. To avoid the extra headroom required by conventional current sources, the sensor’s diode-connected BJTs are biased by precharging sampling capacitors to the supply voltage and then discharging...

High-Energy Radiation Effects on Silicon NPN Bipolar Transistor Electrical Performance: A Study with 1 MeV Proton Irradiation

This study investigates the degradation of the silicon NPN transistor’s emitter-base junction, specifically the 2N2219A model, under both forward and reverse polarization. We examine the current–voltage characteristics under the influence of 1 MeV proton irradiation at various fluencies, which are 5.3×108,5.3×1010,5×1011,5×1012, and 5×1013...

A 210 nW NPN-Based Temperature Sensor With an Inaccuracy of ±0.15 °C (3σ) From −15 °C to 85 °C Utilizing Dual-Mode Frontend

This letter describes an NPN-based temperature sensor that achieves a 1-point trimmed inaccuracy of ±0.15 °C (3σ) from -15 to 85 °C while dissipating only 210 nW. It uses a dual-mode frontend to roughly halve the power consumption of conventional frontends. First, two NPNs are used to generate a well-defined PTAT bias current, then this...

An energy-efficient BJT-based temperature sensor with a continuous-time readout

This thesis presents an energy-efficient high-accuracy temperature sensor that combines a BJT front-end with a continuous-time readout circuit. Its front-end is based on PNP transistors, which, compared to NPNs, are more widely available in CMOS processes and less sensitive to stress. In this design, proportional-to-absolute-temperature (PTAT)...

A BJT-Based CMOS Temperature Sensor with Duty-Cycle-Modulated Output and ±0.5°C (3σ) Inaccuracy from -40 °c to 125 °c

This brief presents a 0.65% relative inaccuracy CMOS temperature sensor with a duty-cycle-modulated (DCM) output. It uses a BJT-based front-end to generate a proportional to absolute temperature voltage (V_{PTAT}) and a complementary to absolute temperature voltage (V_{CTAT}), which are then modulated to a digital-friendly duty-cycle output....

A Continuous-Time BJT-Based Temperature-to-Digital Converter

This thesis presents a BJT-based CMOS temperature-to-digital converter (TDC). With a continuous-time readout, the TDC avoids the kT/C noise limit incurred by previous discrete-time (switched-capacitor) TDCs. An energy-efficient BJT front-end generates single PTAT and CTAT currents for being digitized by a delta-sigma modulator through a linear...

A BJT-Based Temperature-to-Digital Converter With a 0.25 C 3 $\sigma$ -Inaccuracy From-40 C to 180 C Using Heater-Assisted Voltage Calibration

This article presents a BJT-based temperature-to-digital-converter (TDC) that achieves ±0.25 °C 3 sigma -inaccuracy from -40 °C to +180 °C after a heater-assisted voltage calibration (HA-VCAL). Its switched-capacitor (SC) ADC employs two sampling capacitors and, thus, the minimum number of critical sampling switches, which minimizes the...

A Programmable Temperature Switch

Temperature threshold sensors facilitate temperature protection in microprocessors by indicating when the processor gets overheated or too cold. This thesis presents a BJT based temperature sensor with a programmable temperature threshold from -40°C to 150°C. Comparison of a CTAT voltage with a PTAT voltage gives a one-bit digital output when...

An energy-efficient BJT-based Temperature-digital converter based on a Continuous-Time Readout

This thesis presents the most energy-efficient BJT-based CMOS temperature-to-digital converter (TDC) reported to date. It is based on a continuous-time front-end, which avoids the kT/C noise limit incurred by previous discrete-time (switched-capacitor) front-ends. An energy-efficient capacitively-coupled instrumentation amplifier (CCIA) boosts...

Integration of 555 temperature sensors into a 64 × 192 CMOS image sensor

In this work, a novel approach for measuring relative temperature variations across the active area of a CMOS image sensor itself is presented. 555 Image pixels have been replaced by temperature sensors pixels (Tixels) in the same pixel array layer. Both sensors, pixels and Tixels, utilize the same readout structure to obtain the data. This...

A CMOS Bandgap Temperature Sensor for Cryogenic Applications

Cryogenic temperature sensors are finding broadened applications. Such applications include: Cryosurgery [1.3], quantum computing, deep-space probes and planetary missions, satellite communications systems and space-based radar, ultra-high-speed/high sensitivity instrumentation systems, medical electronics (e.g. CT scanner), superconductor...

Characterization of pure boron depositions integrated in silicon diodes for nanometer-deep junction applications

Doping technologies for formation of ultrashallow and highly-doped p+ junctions are continuously demanded to face the challenges in front-end processing that have emerged due to the aggressive downscaling of vertical dimensions for future semiconductor devices. As an alternative to implantations, current solutions are based on in-situ boron (B)...

Improved RF Devices for Future Adaptive Wireless Systems Using Two-Sided Contacting and A1N Cooling

This paper reviews special RF/microwave silicon device implementations in a process that allows two-sided contacting of the devices: the back-wafer contacted silicon-on-glass (SOG) substrate-transfer technology (STT) developed at DIMES. In this technology, metal transmission lines can be placed on the low-loss glass substrate, while the...

Characterization and AlN cooling of thermally isolated bipolar transistors

Nowadays, electrothermal effects (ET) are posing fundamental issues in nearly all branches of micro- and nano-electronics. Due to either a high power dissipation level or to the aggressive electrical isolation schemes adopted to increase the speed, both high and low power devices are affected by ET effects that limit their reliability and cause...