German mixed-signal specialist X-FAB Semiconductor has made available a 650V smart power technology (XD10H) based on a trench-isolated silicon-on-insulator (SOI) process.
The XD10H technology is aimed at power net applications up to 230V. The modular process combine double diffused metal oxide semiconductor (DMOS), bipolar and 1micron complementary metal oxide semiconductor (CMOS) processing steps with dielectric insulation. This approach enables the integration of a wide variety of MOS and bipolar devices with different voltage levels.
In addition to predefined 650V and 350V n-channel DMOS transistors with different on-resistances, CMOS transistors are available with voltage levels from 5-20V. Complex CMOS logic also can be integrated, based on 1micron design rules.
The core process module has a 650V breakdown voltage for the HV DMOS section providing trench insulation, single-level poly with gate oxide and a third power metal layer. Resulting chip sizes for devices requiring 650V insulation will be significantly smaller using XD10H with the trench (dielectric) insulated devices compared to technology using junction insulation for high-voltage devices.
Main target applications for this technology include analogue switch ICs, driver ICs for capacitive, inductive and resistive loads, and electroluminescent (EL)/piezo driver ICs for applications using a 230V net supply. X-FAB also offers comprehensive design support including a design kit with libraries, models and documentation.
austriamicrosystems claims the world's smallest 10-bit multiple output magnetic rotary encoder IC, the AS5040. The system-on-chip integrates field sensing Hall elements, analogue front-end and digital signal processing in a single device.
The company believes that the AS5040 is ideal for industrial applications including motion control, robotics, brush-less DC motor commutation and power tools. In the automotive industry it could be used for steering wheel and gas pedal position sensing, headlight control, power seat position indicators and transmission box encoders. The AS5040 operates in a contactless system with a small magnet that is placed either above or below the device. The device can detect 1024 positions in a full 360-degree magnet turn.
Ralf Kodritsch, marketing manager for the Sensors & Automation division, comments: "Its small physical dimensions and robustness makes this device a reliable and cost-effective alternative to optical encoders. The contactless position sensing and wide temperature operating range makes this device ideally suited for harsh environments. The AS5040 has been tailored for applications with high resolution and accuracy requirements such as steering wheel position detection or industrial motion control."
The AS5040 provides absolute, incremental and pulse width modulated digital output signals simultaneously. The user programmable index / zero position enables rotational speed measurement, while a synchronous serial interface output provides absolute position data. The AS5040 can be configured to specific customer requirements by programming the integrated one-time programmable internal register. An internal voltage regulator allows the AS5040 to operate at either 3.3V or 5V. The AS5040 also includes a failure detection feature that monitors the magnet placement during operation. The operating temperature range is from -40degreesC to +125degreesC.
Fairchild Semiconductor says that its PowerTrench MOSFET process yields exceptionally low values for Miller charge (Qgd) with one device already produced with 3nC (typical). The process can also reduce on-resistance (RDS(on)) to 11.3mOhms maximum in the same Fairchild product. Total gate charge (Qg) and the gate-drain charge to gate-source charge (Qgd:Qgs) ratio have also been enhanced.
These improvements are seen as resulting in superior switching performance and thermal efficiencies when used in synchronous buck power supplies as used by notebook computers. In this application, the typically large input-to-output voltage ratio and large voltage swing across the high-side MOSFET often leads to excessive switching losses if the device cannot turn on and off quickly.
The benefits of low Qgd are decreased switching losses and reduced "dead time" for improved regulation. A favourable Qgd:Qgs ratio offers immunity against false gate triggering that result in shoot-through currents between switching MOSFETs when employed as a synchronous rectifier. Low RDS(on) is critical in minimising conduction losses and low Qg reduces the power consumed to turn the MOSFET on and off each cycle. Two new 30V MOSFETs from Fairchild, the FDS6294 and FDS7288N3, use the improved fast-switching technology with hoped for applications in notebook computers and point of load (POL) converter designs.
Researchers in the USA have studied ferroelectric fatigue using x-ray microdiffraction (Nature Materials, June 2004). The team finds two regimes of fatigue - one for low-field switching and another for high-field. In the low field regime, the fatigue can be reversed with higher field pulses. This is not possible in the high-field switching. This is due to non-reversible crystallographic relaxation of the epitaxial ferroelectric film, the researchers find.
The scientists used the Advanced Photon Source at the Argonne US national laboratory. In addition to Argonne, contributors to the work came from the universities of Wisconsin (Madison) and Michigan (Ann Arbor), and Bell Laboratories, Lucent Technology.