Semiconductors & ICs

Multifunctional Logic Gate Controlled by Temperature

This circuit performs different logic functions at different temperatures. The figure is a schematic diagram of a complementary metal oxide/semiconductor (CMOS) electronic circuit that has been designed to function as a NAND gate at a temperature between 0 and 80 °C and as a NOR gate at temperatures from 120 to 200 °C. In the intermediate temperature range of 80 to 120 °C, this circuit is expected to perform a function intermediate between NAND and NOR with degraded noise margin. The process of designing the circuit and the planned fabrication and testing of the circuit are parts of demonstration of polymorphic electronics — a technological discipline that emphasizes designing the same circuit to perform different analog and/or digital functions under different conditions. In this case, the different conditions are different temperatures.

Posted in: Semiconductors & ICs, Briefs

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Multifunctional Logic Gate Controlled by Supply Voltage

This circuit performs different logic functions at different levels of supply voltage. The figure is a schematic diagram of a complementary metal oxide/semiconductor (CMOS) electronic circuit that functions as a NAND gate at a power-supply potential (Vdd) of 3.3 V and as NOR gate for Vdd = 1.8 V. In the intermediate Vdd range of 1.8 to 3.3 V, this circuit performs a function intermediate between NAND and NOR with degraded noise margin. Like the circuit of the immediately preceding article, this circuit serves as a demonstration of the evolutionary approach to design of polymorphic electronics — a technological discipline that emphasizes evolution of the design of a circuit to perform different analog and/or digital functions under different conditions. In this instance, the different conditions are different values of Vdd.

Posted in: Semiconductors & ICs, Briefs, TSP

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FETs Based on Doped Polyaniline/Polyethylene Oxide Fibers

Advantages include tailorability of electronic properties and low power demands. A family of experimental highly miniaturized field-effect transistors (FETs) is based on exploitation of the electrical properties of nanofibers of polyaniline/ polyethylene oxide (PANi/PEO) doped with camphorsulfonic acid. These polymer-based FETs have the potential for becoming building blocks of relatively inexpensive, low-voltage, high-speed logic circuits that could supplant complementary metal oxide/semiconductor (CMOS) logic circuits.

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Carbon-Nanotube Schottky Diodes

These devices can outperform conventional Schottky diodes at submillimeter wavelengths. Schottky diodes based on semiconducting single-walled carbon nanotubes are being developed as essential components of the next generation of submillimeter- wave sensors and sources. Initial performance predictions have shown that the performance characteristics of these devices can exceed those of the state-of-the-art solid-state Schottky diodes that have been the components of choice for room-temperature submillimeter- wave sensors for more than 50 years.

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Dual Common Planes for Time Multiplexing of Dual-Color QWIPs

With external control, commercial single-color readout integrated circuits could be used. A proposed improved method of externally controlled time multiplexing of the readouts of focal plane arrays of pairs of stacked quantum well infrared photodetectors (QWIPs) that operate in different wavelength bands is based on a dual detector common plane circuit configuration. The method would be implemented in a QWIP integrated-circuit chip hybridized with a readout integrated circuit (ROIC) chip.

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MMIC Power Amplifier Puts Out >40 mW From 75 to 110 GHz

This amplifier operates over the full frequency band of the WR-10 waveguide. A three-stage monolithic microwave integrated circuit (MMIC) W-band amplifier has been constructed and tested in a continuing effort to develop amplifiers as well as oscillators, frequency multipliers, and mixers capable of operating over wide frequency bands that extend above 100 GHz. There are numerous potential uses for MMICs like these in scientific instruments, radar systems, communication systems, and test equipment operating in this frequency range. This amplifier can be characterized, in part, as a lower-frequency, narrower band, higher-gain version of the one described in “Power Amplifier With 9 to 13 dB of Gain from 65 to 146 GHz” (), NASA Tech Briefs, Vol. 25, No. 1 (January 2001), page 44. This amplifier includes four InP high-electron-mobility transistors (HEMTs), each having a gate periphery of 148 µm. In the third amplifier stage, two of the HEMTs are combined in parallel to maximize the output power. The amplifier draws a current of 250 mA at a supply potential of 2.5 V.

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Multiplexing Transducers Based on Tunnel-Diode Oscillators

Compact, low-power transducers could operate over wide temperature ranges. Multiplexing and differential transducers based on tunnel-diode oscillators (TDOs) would be developed, according to a proposal, for operation at very low and/or widely varying temperatures in applications that involve requirements to minimize the power and mass of transducer electronic circuitry. It has been known since 1975 that TDOs are useful for making high-resolution (of the order of 10–9) measurements at low temperatures. Since that time, TDO transducers have been found to offer the following additional advantages, which the present proposal is intended to exploit:

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