Semiconductors & ICs

Source-Coupled, N-Channel, JFET-Based Digital Logic Gate Structure Using Resistive Level Shifters

A circuit topography is used to create usable, digital logic gates using N (negatively doped) channel junction field effect transistors (JFETs), load resistors, level shifting resistors, and supply rails whose values are based on the DC parametric distributions of these JFETs. This method has direct application to the current state-of-the-art in high-temperature (300 to 500 °C and higher) silicon carbide (SiC) device production, and defines an adaptation to the logic gate described in U.S. Patent 7,688,117 in that, by removing the level shifter from the output of the gate structure described in the patent (and applying it to the input of the same gate), a source-coupled gate topography is created. This structure allows for the construction AND/OR (sum of products) arrays that use far fewer transistors and resistors than the same array as constructed from the gates described in the aforementioned patent. This plays a central role when large multiplexer constructs are necessary; for example, as in the construction of memory.

Posted in: Briefs, TSP, Semiconductors & ICs, Electronic equipment, Transistors, Semiconductors


Monitoring Digital Closed-Loop Feedback Systems

Designed-in test circuitry enables determination of performance margins and performance trends.A technique of monitoring digital closed-loop feedback systems has been conceived. The basic idea is to obtain information on the performances of closed-loop feedback circuits in such systems to aid in the determination of the functionality and integrity of the circuits and of performance margins.

Posted in: Briefs, TSP, Semiconductors & ICs, Integrated circuits, Semiconductors, Performance tests


Semiconductor Laser Technology Chosen for Space LIDAR

Single-frequency semiconductor laserRedfern Integrated Optics (RIO)Santa Clara, has chosen Redfern Integrated Optics to further develop a single-frequency, narrow-linewidth semiconductor laser suitable for spaceflight operation. RIO’s external-cavity semiconductor laser technology is based on the hybrid integration of an indium phosphide (InP) gain chip and a planar lightwave circuit (PLC) with Bragg gratings. Packaged in a standard 14-pin compact “butterfly” package, the laser is characterized by a single-frequency output in the 1550-nm spectral region with a linewidth less than 2 kHz, low phase noise, low relative intensity noise (RIN), and high immunity to vibrations in a wide range of operating temperatures.

Posted in: Application Briefs, Lasers & Laser Systems, Semiconductors & ICs


Interface Supports Multiple Broadcast Transceivers for Flight Applications

A wireless avionics interface provides a mechanism for managing multiple broadcast transceivers. This interface isolates the control logic required to support multiple transceivers so that the flight application does not have to manage wireless transceivers. All of the logic to select transceivers, detect transmitter and receiver faults, and take autonomous recovery action is contained in the interface, which is not restricted to using wireless transceivers. Wired, wireless, and mixed transceiver technologies are supported.

Posted in: Briefs, Semiconductors & ICs, Avionics, Data exchange, Integrated circuits, Wireless communication systems


FPGA Sequencer for Radar Altimeter Applications

A sequencer for a radar altimeter provides accurate attitude information for a reliable soft landing of the Mars Science Laboratory (MSL). This is a field-programmable-gate-array (FPGA)-only implementation. A table loaded externally into the FPGA controls timing, processing, and decision structures. Radar is memory-less and does not use previous acquisitions to assist in the current acquisition. All cycles complete in exactly 50 milliseconds, regardless of range or whether a target was found.

Posted in: Briefs, Semiconductors & ICs, Altimeters, Attitude control, Integrated circuits, Radar, Spacecraft guidance, Entry, descent, and landing


SAD5 Stereo Correlation Line-Striping in an FPGA

High precision SAD5 stereo computations can be performed in an FPGA (field-programmable gate array) at much higher speeds than possible in a conventional CPU (central processing unit), but this uses large amounts of FPGA resources that scale with image size. Of the two key resources in an FPGA, Slices and BRAM (block RAM), Slices scale linearly in the new algorithm with image size, and BRAM scales quadratically with image size. An approach was developed to trade latency for BRAM by sub-windowing the image vertically into overlapping strips and stitching the outputs together to create a single continuous disparity output.

Posted in: Briefs, TSP, Semiconductors & ICs, Mathematical models, Antennas, Architecture, Integrated circuits


Miniature Sapphire Acoustic Resonator — MSAR

Q values as high as 108 may be achieved at room temperature.A room temperature sapphire acoustics resonator incorporated into an oscillator represents a possible opportunity to improve on quartz ultrastable oscillator (USO) performance, which has been a staple for NASA missions since the inception of spaceflight. Where quartz technology is very mature and shows a performance improvement of perhaps 1 dB/decade, these sapphire acoustic resonators when integrated with matured quartz electronics could achieve a frequency stability improvement of 10 dB or more. As quartz oscillators are an essential element of nearly all types of frequency standards and reference systems, the success of MSAR would advance the development of frequency standards and systems for both ground-based and flight-based projects.

Posted in: Briefs, Semiconductors & ICs, Product development, Standardization, Semiconductors, Acoustics


The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.