Abstract: An apparatus and method are disclosed which provide a substantially linear relationship between an input signal, such as an input voltage or current, and a predetermined parameter, such as a frequency response or capacitance of a parallel plate capacitor or varactor. The apparatus comprises a square root converter and a logarithmic generator. The square root converter is adapted to provide a square root signal which is substantially proportional to a square root of the input signal. In the various embodiments, the logarithmic generator is adapted to provide an applied signal which is substantially proportional to a sum of a logarithm of the input signal plus the square root of the input signal. The applied signal is a pre-distorted signal which generally has a non-linear relation to the predetermined parameter and which, when applied, allows the predetermined parameter to vary substantially linearly with the input signal.

Abstract: A micromachined device such as a solid-state liquid chemical sensor for receiving and retaining a plurality of separate liquid droplets at desired sites, a method of making the device and a method of using the device are provided. The technique works for both aqueous and solvent-based solutions. The device includes a substrate having an upper surface, and a first set of three-dimensional, thin film well rings patterned at the upper surface of the substrate. Each of the wells is capable of receiving and retaining a known quantity of liquid at one of the desired sites through surface tension. A method for patterning a membrane/solvent solution results in reproducibly-sized, uniformly-thick membranes. The patterning precision of this method allows one to place the membranes closer together, making the sensors smaller and less expensive, and the uniform film thickness imparts reproducibility to the sensors.

Abstract: Laminated devices and methods of making same are provided. A fluidic channel is formed in the inner layers of a laminate such as multilayer printed circuit board (PCB) and a hole is opened to the outer layers to allow fluid's access to a chip which contains chemical sensors. Several diaphragms are formed on each side of the chip access hole using the PCB as their substrate. Electromagnetic actuation of these diaphragms by solenoids housed inside the PCB drives or pumps fluid through the channel in a peristaltic fashion. By employing various channel geometries and/or the deposition of hydrophobic/hydrophillic layers, valves are provided in the channels.

Abstract: A microsystem for determining clotting time of blood and a low-cost, single-use device for use therein are provided wherein the device has no moving parts or expensive optical sensors or magnets. The device includes a microfluidic channel and a microsensor at least partially in fluid communication with the channel. By analyzing changes in the sensor as a drop of blood flows down the microfluidic channel, the time at which the blood clots can be determined.

Abstract: A micromachined device such as a solid-state liquid chemical sensor for receiving and retaining a plurality of separate liquid droplets at desired sites, a method of making the device and a method of using the device are provided. The technique works for both aqueous and solvent-based solutions. The device includes a substrate having an upper surface, and a first set of three-dimensional, thin film well rings patterned at the upper surface of the substrate. Each of the wells is capable of receiving and retaining a known quantity of liquid at one of the desired sites through surface tension. A method for patterning a membrane/solvent solution results in reproducibly-sized, uniformly-thick membranes. The patterning precision of this method allows one to place the membranes closer together, making the sensors smaller and less expensive, and the uniform film thickness imparts reproducibility to the sensors.

Abstract: A micromachined device such as a solid-state liquid chemical sensor for receiving and retaining a plurality of separate liquid droplets at desired sites, a method of making the device and a method of using the device are provided. The technique works for both aqueous and solvent-based solutions. The device includes a substrate having an upper surface, and a first set of three-dimensional, thin film well rings patterned at the upper surface of the substrate. Each of the wells is capable of receiving and retaining a known quantity of liquid at one of the desired sites through surface tension. A method for patterning a membrane/solvent solution results in reproducibly-sized, uniformly-thick membranes. The patterning precision of this method allows one to place the membranes closer together, making the sensors smaller and less expensive, and the uniform film thickness imparts reproducibility to the sensors.

Abstract: An integrated circuit is disclosed that includes one or more blocks of switching logic (comprised of transistors) connected between a power supply and a common node. A control transistor connects the common node to ground. The control transistor has a higher threshold voltage level than the voltage threshold level(s) of the transistors that comprise the switching logic blocks. A bias generator provides a positive bias to the body of the control transistor when the control transistor is “on.

Abstract: Laminated devices and methods of making same are provided. A fluidic channel is formed in the inner layers of a laminate such as multilayer printed circuit board (PCB) and a hole is opened to the outer layers to allow fluid's access to a chip which contains chemical sensors. Several diaphragms are formed on each side of the chip access hole using the PCB as their substrate. Electromagnetic actuation of these diaphragms by solenoids housed inside the PCB drives or pumps fluid through the channel in a peristaltic fashion. By employing various channel geometries and/or the deposition of hydrophobic/hydrophillic layers, valves are provided in the channels.

Abstract: MEMS-based, computer system, clock generation and oscillator circuits and LC-tank apparatus for use therein are provided and which are fabricated using a CMOS-compatible process. A micromachined inductor (L) and a pair of varactors (C) are developed in metal layers on a silicon substrate to realize the high quality factor LC-tank apparatus. This micromachined LC-tank apparatus is incorporated with CMOS transistor circuitry in order to realize a digital, tunable, low phase jitter, and low power clock, or time base, for synchronous integrated circuits. The synthesized clock signal can be divided down with digital circuitry from several GHz to tens of MHz—a systemic approach that substantially improves stability as compared to the state of the art. Advanced circuit design techniques have been utilized to minimize power consumption and mitigate transistor flicker noise upconversion, thus enhancing clock stability.

Abstract: Screen printing technology is employed in the batch fabrication of the contacts and polymeric membranes of solid-state ion-selective sensors. The process achieves high yield with very reproducible results. Moreover, membrane thickness can easily be predetermined, as it is directly related to the thickness of the screen or stencil. The process of the present invention is compatible with many integrated circuit manufacturing technologies, including CMOS fabrication. Advantageous polymeric membrane paste compositions include a polyurethane/hydroxylated poly(vinyl chloride) compound and a silicone-based compound in appropriate solvent systems to provide screen-printable pastes of the appropriate viscosity and thixotropy.

Abstract: A memory cell (i.e. CMMC) for use in GaAs circuits such as MESFETs wherein read and write operations can both be performed using as few as two access transistors biased as current mirrors to driver transistors of the cell. This new memory cell offers larger read access currents for faster access times and also faster write times than in a conventional memory cell. This cell does not require that the driver transistors be scaled with respect to the access transistors, resulting in a smaller cell area. In the CMMC, the gate of each access transistor is biased by a storage node voltage. The source node of each access transistor is biased by a word line which is pulled low, towards ground. As a result, each access transistor has a gate-source voltage ofV.sub.GS (access)=V.sub.CS +V.sub.CG -V.sub.WORDwhere V.sub.CS is the cell storage voltage (with respect to cell ground), V.sub.CG is the cell ground voltage and V.sub.WORD is the word line voltage at the cell.

Abstract: A polyimide matrix is employed to form a substance-sensitive membrane which is particularly suited for installation on a solid state sensor. Polyimide, dissolved in a solvent, such as N,N-dimethylformamide, or N-methyl-2-pyrrolidone (polyimide encapsulant), is combined with an ionophore, plasticizer, and a lipophilic additive. The ionophore may be a calcium ionophore, an ammonium ionophore, or any other ionophore. The membrane may also incorporate, or may be covered by, a bioactive agent, such as an enzyme, an immunochemical, bacteria, antibody, virus, or antigen. The plasticizer is one or both of dimethyl phthalate and diethylene glycol dibenzoate. The lipophilic additive may be potassium tetrakis(p-chlorophenyl)borate. The resulting substance-sensitive membrane has electrochemical properties which compare favorably to those of conventional PVC membranes, and exhibit significantly greater adhesion to glasses and semiconductor substrate materials.

Abstract: A temperature limiting control for an electrical heating appliance such as a ceramic hob comprises switch means (11) and a temperature sensor (10) connnected thereto. The temperature sensor comprises an elongate reference member (12) of ceramic or other low expansion material and an elongate expansion member (13), for example a tape of high chrome steel, relative expansion of the two members operating the switch. The switch (11) and reference member (13) lie to one side of the expansion member (12) so that the latter may be placed closely adjacent the top (2) of the appliance.

Abstract: A silicone matrix is employed to form a substance-sensitive membrane which is particularly suited for installation on a solid state sensor. The ionophore may be a potassium ionophore, an ammonium ionophore or any other ionophore. The membrane may be coupled to the molecule of interest through a bioactive agent, such as an enzyme, an immunochemical, bacteria, antibody, virus, or antigen. The resulting substance-sensitive membrane has electrochemical properties which compare favorably to those of conventional PVC membranes, and exhibit significantly greater adhesion to glasses and semiconductor substrate materials. The improved adhesion will prolong the life of the sensors and prevent the formation of electrolyte shunts which have been known to render solid state sensors inoperative.

Abstract: An integrated circuit for a miniaturized solid-state chemical sensor. The integrated circuit includes a chemical-selective membrane which provides an electric signal in response to contact with a particular chemical or group of chemicals in a fluid. The chemical-selective membrane is attached to the integrated circuit by a membrane definition layer. An electrically conductive layer beneath the membrane definition layer provides electrical contact between the chemical-selective membrane and one of the input transistors of the voltage-follower amplifier. The chemical-selective membrane is formed separately from the gate of the input transistors and is designed as a integrated input to the amplifier. The output of the chemical sensor is a low impedance electric signal represented as a voltage which corresponds to the chemical activity present at the chemical-selective membrane/fluid interface.