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DESIGN & PRODUCTS ANALOG & MIXED SIGNAL Further recent new innovations include High-Layer- Count (HLC) technology giving increased capacitance, and high-temperature devices capable of operating at temperatures up to 300°C to ensure high reliability in demanding applications such as deepwell drilling. In addition, the latest KEMET ”Smart Cap” technology is opening up many new opportunities for customization by integrating extra components in series or parallel, such as resistors, fuses and other Fig. 3: KEMET “Smart Cap” device featuring an integrated bleed resistor with two high-value ceramic capacitors. circuitry (figure 3). Some applications that require a brief energy pulse also require a safety mechanism. This mechanism needs to bleed off the energy when the system is no longer armed for operation. By integrating the resistor into the capacitor stack, customers have a single component with integrated safety. Where bulk capacitance is needed, another option is being developed that eliminates the leadframe so that a stacked capacitor solution can be surface mounted directly to the circuit board (figure 4). In addition to being lighter and lower cost compared to a traditional stack solution, the leadless stack is assembled with materials capable of easily withstanding high solder reflow temperatures. The stacked assembly remains mechanically robust at operating temperatures up to 200°C and higher. In addition to developing products tailored to customers’ needs, other important services include electrical characterization processes that meet the needs of specific end-user applications. These cover aspects such as ESR, ESL and impedance over a range of frequencies and temperatures, as well as AC life testing, DC life testing up to 300°C and 2000V, pulse and endurance testing, and ripple life testing up to 150°C. Conclusion Continuous innovation of standard ceramic-capacitor products, as well as customization, are vital to keep next-generation electronic products moving forward. Advances in materials, processes, construction and packaging have enabled designers to satisfy increasingly stringent demands for miniaturization, performance improvement and reliability. Fig. 4: Leadframe-free stacked capacitors save weight while boosting high-temperature capability. Time-of-flight sensor has doubled range STMicroelectronics has launched its third-generation timeof flight (ToF) laser ranging sensor, the VL53L1, which brings multi-object detection and multi-array scanning as well as doubling range of operation to above 4.5m. The VL53L1, part of ST’s FlightSense series of sensors, has changes at the silicon and module level including the addition of optical lenses to the module. This allows novel features such as multi-target detection and programmable multi-zone scanning. The VL53L1 is suitavle for robotics, user detection, drones, IoT, and wearable applications. The sensor module integrates a VCSEL that emits at a wavelength of 940nm, a processor core and a SPAD photon detector. The addition of the optical lens system increases the photon detection rate to boost the module’s ranging performance. The embedded microcontroller manages the ranging function. The VL53L1 performs a full measurement operation in as little as 5ms and for autofocus applications in smartphones, the sensor detects objects twice as fast as earlier-generation devices. The module measures 4.9mm by 2.5mm by 1.56mm. The VL53L1 is an I2C capable module that is in production and available now. STMicroelectronics www.st.com Toshiba claims most efficient ADC The 12-bit resolution ADC is suitable for next-generation wireless LANs while the circuits power efficiency is the world’s highest, three times that of current ADCs, Toshiba claimed. The company has presented a paper on the circuit at the International Solid-State Circuits Conference in San Francisco. The circuit is a 0.7V, 12-bit resolution successive approximation register ADC that operates at up to 120Msamples/s with an energy consumption of 12.8fJ per conversion. It has been implemented in 28nm CMOS. Target speeds for wireless LANs continue to increase and one key to achieving that is higher conversion accuracy which it tunr depends on higher multiplication accuracy in the amplifiers of the ADC. By conventional methods that would increase power consumption in the op amp and result in a trade-off between conversion accuracy and power efficiency. Toshiba has used the idea of a floating or “virtual ground” to improve multiplication accuracy and adding a comparator to detect the virtual ground voltage and a controlling amplifier to manipulate it. The digital amplifier mostly comprises digital circuits that consume less power than analog circuits, because power-hungry op amps are eliminated and current flows only when the signals switch. Furthermore, digital amplifier performance can be improved greatly by CMOS scaling, which simultaneously lowers manufacturing costs. Toshiba www.toshiba.co.jp 32 Electronic Engineering Times Europe March 2017 www.electronics-eetimes.com


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