Showing papers by "Motorola published in 1971"

Amorphous silicon film as a uv filter

Abstract: There is disclosed the use of a thin amorphous silicon film as a narrow-band rejection filter which is used either as a mask to UV light in semiconductor device processing or is used as a protective shield for solar cells which overheat in the presence of ultraviolet light.

Shielding techniques for r.f. circuitry

Abstract: A technique for shielding R.F. circuitry is disclosed wherein thin metal strips are formed by chemical etching, and include bend or fold grooves similarly etched, the strips being bent into the desired configuration at the time of assembly. Printed circuit boards with the components all on one side and the connections all on the other are placed in the compartments formed by the bent metal strips. Tabs are provided between the edges of the strips to hold the boards in place. Syntatic foam may be placed in the compartments on the component side and visco-elastic damping foam and or double sided pressure sensitive foam tape is placed between the bottom of the printed circuit board and the bottom shield cover. Covers also formed by chemical etching are attached to the top and bottom of the compartments and puncture resistant tape may be mounted on the inside of the top and bottom covers.

Intermodulation rejection capabilities of field-effect transistor radio frequency amplifiers and mixers

Abstract: Mixers and amplifier circuits are disclosed which may include a plurality of identical FETs connected in parallel to form a composite FET. The decreased input impedance of the composite FET as compared to the input impedance of a single FET results in a decrease in intermodulation. The composite FET may also be a power or large signal FET. In either case, the pinch-off voltage of the composite FET can also be increased to provide a still further decrease in intermodulation.

Multiple lead integrated circuit device and frame member for the fabrication thereof

Abstract: A semiconductor device, and more specifically an integrated circuit device, is fabricated by mounting on a one-piece metallic frame member one or more integrated circuit structures or semiconductor units. The frame member is provided with a plurality of groups of metallic parts, and each group comprises a mounting portion or portions for corresponding integrated circuit structure and frame means for the group. Each such group in the frame member also comprises in its metallic parts, metal means or lead portions which are electrically connected with contacts on the integrated circuit structure. To help to stabilize the position of the lead portions in a group while the ultimate device is being fabricated and to serve as a plastic-flashlimiter when the active parts of the semiconductor devices are being plastic-encapsulated in a mold cavity under pressure molding, integral metallic lead spacers extend between adjacent lead portions. The frame means and lead spacers are severed during the complete fabricating cycle.

In-band data transmission system

Abstract: An information transmission system for transmitting data signals simultaneously with audio signals in an audio channel includes a gate circuit at the transmitting unit for interrupting the transmitted audio at a rate controlled by the data signal, and a detector at the receiving unit for detecting the interruptions in the audio and reconstructing the data signal from the interruptions. The duration of the interruptions is selected to be short enough so as not to be readily detectable audibly. The system is suitable for use in a multiple radio-receiver system wherein signals are transmitted from spaced receivers to a central station with data signals indicating the quality of the signals received at each receiver.

Threshold voltage variations with temperature in MOS transistors

Abstract: Variations with temperature in the threshold voltage of n- and p-channel MOS transistors are obtained by calculation as well as measurement, with the results comparing quite closely. The amount of voltage change per °C under normal operating conditions is found to be dependent upon the channel doping concentration. The calculations show that for either n- or p-channel devices the voltage change per °C is -4 mV/°C for an impurity concentration of 3 × 1016/cm3and -2 mV/°C for an impurity concentration of 1015/cm3. This information is important because if the MOS transistor is subjected to a changing temperature environment, the accompanying threshold voltage change may be intolerable.

Circuit for coupling radio receiver and radio transmitter to a common antenna for duplex operation

Abstract: Antenna coupling circuit for duplex radio transmission and reception by use of a common antenna (duplexer), including plurality of helical resonator sections provided within conductive enclosures in a conductive housing. A helical winding is provided in each enclosure having one end connected to the housing, and an adjustable conductive stud forms a capacitor with the other end of the winding. The winding and enclosure form a parallel tuned resonator, and the series capacitor forms therewith a series tuned circuit. One series tuned circuit at the receiver frequency is coupled to the antenna by a transmission line having a length equal to an odd multiple of a quarter wave length at the transmitter frequency, and this junction is connected to the transmitter through a circuit which may include additional tuned circuits. A second series tuned circuit at the transmitter frequency is coupled to the antenna by a transmission line having a length equal to an odd multiple of a quarter wave length at the receiver frequency, and this junction is connected to the receiver through a circuit which may include additional tuned circuits. A reactance may be connected in parallel with the first series tuned circuit to provide an anti-resonant circuit at the transmitter frequency, and a different reactance may be connected in parallel with the second tuned circuit to provide an anti-resonant circuit at the receiver frequency. Additional resonator sections can be connected in the transmitter and/or receiver branches of the circuit.

Receiving antenna for miniature radio receiver

Abstract: Receiving antenna for miniature radio receiver formed by conducting U-shaped member having substantially parallel elongated arms which form sides of the housing of the receiver and a connecting portion which forms one end of the housing. When the receiver is in the normal position for use, the arms are positioned vertically with the connecting portion at the top, and the U-shaped member acts as an inductive loop antenna to detect the H-field of the electro-magnetic wave. A reactance network, which is capacitive in the frequency range of interest, is connected to the open ends of the arms. The reactance network can be adjustable to tune the antenna for various frequencies, the antenna having been found suitable for use in the frequency range from 148 to 173 megacycles.

Light emitting diode display for electronic timepiece

Abstract: There is disclosed a light emitting diode timepiee display in which the output of the light emitting diode display is controlled with respect to ambient lighting conditions so as to provide the maximum amount of contrast with a minimum amount of power consumption. The contrast between the light emitted by the light emitting diodes and the ambient light in the immediate vicinity of the timepiece is enhanced by the use of absorption type filters, truncated pyramid type apertures in the display cover plate and a control circuit which adjusts the intensity of the output of the light emitting diodes to the ambient light conditions. Thereis further provided a series of solar cells on the face of the display, which recharge the timepiece batteries during ultra-high ambient light conditions and which supply additional power to the light emitting diodes during high ambient lighting conditions so as to increase the output of the light emitting diodes. This enhances the contrast of the diodes during high ambient lighting conditions while at the same time providing an additional source of power in parallel with that of the timepiece battery so as to increase the effective lifetime of the battery. Power distribution between the solar cells and the battery is controlled by the aforementioned control circuit. In addition, the control circuit varies the power available to the light emitting diodes such that in low ambient lighting conditions a lesser amount of power is delivered to the light emitting diodes while in high ambient lighting conditions, a larger amount of power is delivered to the diodes. In this manner the aforementioned contrast is kept constant and at that level which corresponds to the minimum level necessary for ready visibility. In addition, several structural embodiments are shown, all of which contribute to the enhancement of the light output of the light emitting diodes, the enhancement of display contrast, low power consumption, ease of fabrication, and mechanical stability of the final product.

Gain modified multi-channel audio system

Abstract: A stereo-effect enhancement system for increasing the apparent spatial separation in a multi-channel audio system includes variable gain amplifiers and comparator circuits which compare the amplitudes of the audio input signals and adjust the gain of the variable gain amplifiers in accordance with the ratio of the amplitudes of the audio input signals. Spatially expanded two channel stereo, pseudo three channel stereo, pseudo four channel stereo or automatic stereo balance control may be achieved by variously combining the audio signals from the enhancement system with the unmodified audio input signals.

Process for production of polycrystalline silicon

Abstract: There is disclosed a process for the hydrogen reduction of silicon tetrachloride to produce trichlorosilane. In accordance with the process, hydrogen and silicon tetrachloride vapors are passed through a reaction chamber at relatively high flow rates with approximately 50 mole percent silicon tetrachloride in the mixture. The reaction vessel is held at a temperature of between 900° and 1200° C. This process is a part of an overall system for the production of polycrystalline silicon for the semiconductor industry.

Dipole antenna arrangement for radio with separate speaker-microphone assembly

Abstract: A speaker microphone assembly, used with a portable radio unit containing receiving and transmitting equipment for receiving and transmitting radio signals, includes a housing with a helical antenna element mounted to the top wall to form one element of a dipole antenna. A coaxial cable having inner and outer conductors is connected from the portable unit equipment to the speaker microphone housing. The center conductor is connected to the helical antenna and the outer conductor is terminated in the housing at a first point which is ground potential. A second outer conductor surrounds and is insulated from the first outer conductor, and is connected to the first outer conductor at the first point. The second outer conductor extends for a predetermined length along the first outer conductor to form the other element of the dipole antenna.

Digital frequency and/or phase detector charge pump

Abstract: A digital frequency and/or phase detector is disclosed wherein a time varying reference signal is received in one bistable device only, a time varying feedback signal is received in another bistable device only, and corresponding portions of each cycle of said signals are compared in digital logic circuitry supplied by the outputs of the two bistable devices. A logic signal developed by the first occurrence of the corresponding portion of one of the time varying signals effects, through the logic circuitry, turn on of a responsive circuit, a logic signal developed by the subsequent occurrence of the corresponding portion of the other of said time varying signals effects, through the logic circuitry, turn off of such responsive circuit, and an analog signal is developed by such responsive circuit in relation to the time interval between the occurence of the corresponding portions of the time varying signals.

Housing assembly for miniature radio apparatus with self contained battery

Abstract: Housing assembly for miniature radio apparatus, such as a radio pager, having a molded frame member which supports the chassis and forms one end and two opposite sides of a housing. A U-shaped cover member slides in grooves in the frame member to form the other end and the other two sides of the housing, thereby providing a completely enclosed housing. Space for a battery is provided adjacent the end of the housing formed by the frame member, and the cover can slide with respect to the frame member to open the housing at that end to afford access to the battery. A detent is provided on the frame member which engages the cover member to hold the cover completely closed. A clip for holding the radio apparatus in a pocket includes a button to release the detent to permit the cover to slide for access to the battery. A second detent prevents further movement of the cover with respect to the housing preventing access to the radio chassis, with a key being required to release the second detent for removal of the cover from the frame member. Both single use and rechargeable batteries can be used, and contacts are provided in the housing for connecting the rechargeable battery to a charger.

Voltage and current regulator with automatic switchover

Abstract: A system for energizing an inductive load includes a voltage regulator for providing a constant voltage across the load until the current builds up to a particular value, and a current regulator which then takes over to provide a constant holding current at a lower value. The voltage regulator may include a closed loop for holding the voltage across the inductive load constant or may respond to a regulated voltage value to control a power stage for providing a constant voltage. The voltage across a sensing resistor in the power stage controls the crossover from the voltage regulation mode, to the current regulation mode and the current regulator automatically resets the reference to control the power stage to provide a constant current of a lower value through the load. The system can be used to supply current to coils of injector valves in a fuel injection system, and may include two power stages for supplying current to two banks of coils. The regulator system is switched from one power stage to the other during successive 180° rotary positions of the engine for both stages.

Controlled anisotropic etching process for fabricating dielectrically isolated field effect transistor

Abstract: There is disclosed an improved junction field effect transistor with dielectric isolation as opposed to isolation by PN junction techniques. The use of the dielectric isolation lowers parasitic capacitance and permits the use of a single gate for the control of the current from the source to the drain of the device. The use of a single gate and the dielectric isolation prevents this parasitic capacitance and the concomitant reduction of the frequency response of the device by eliminating the need for a large area second gate which generates the unwanted parasitic capacitance. In the two gate embodiment of the subject invention, the second gate area is minimized so as to minimize the parasitic capacitance. The gain of the subject device is increased by internally connecting the two gates with a deep diffused region therebetween. There is further disclosed a method for making junction field effect transistors such that the channel width is accurately controlled.

Protective carrier for semiconductor devices

Abstract: A two-piece carrier for flat-pack integrated circuit semiconductor devices includes a nonconductive base member with a recess for the body of a semiconductor device and a plurality of lead receiving slots. A retaining clip placed over the semiconductor device has lead engaging members on each side for retaining and holding the semiconductor device in the carrier. The lead engaging members are plated with aluminum to short the leads of the semiconductor device during shipping and handling, but the retaining clip is loosely retained. When the carrier is inverted and placed on a conventional test fixture, the leads of the semiconductor device are engaged by the contacts of the test fixture and pressed onto the base member, with the retaining clip dropping away from contact with the leads.

Broadband circuit for minimizing the effects of crystal shunt capacitance

Abstract: A crystal controlled oscillator circuit having broadband circuitry for balancing out the effects of the static shunt capacitance of a crystal. A broadband phase inverting network is connected across the crystal to cancel the signal flowing through the crystal as a result of capacitive coupling between the plates. The phase inverting network may include a transformer, a center tapped inductor or a broadband inductance-capacitance network. A capacitor having a capacitance value related to the value of the static shunt capacitance is used in conjunction with the phase inverting network to determine the magnitude of the phase inverted cancellation signal.

Poly-silicon electrodes for c-igfets

Abstract: Poly-silicon electrodes are provided for use with source and drain regions of insulated gate field-effect transistors as well as a method for contacting silicon gate devices utilizing polysilicon electrodes and a single etching step. The single etching step obviates the use of an additional masking operation for forming preohmic holes in the vicinity of the source and drain regions for the device. The provision of preohmic holes at the source and drain regions necessitates large area source and drain regions so as to permit clearance for the metallization through preohmic holes. These large areas decrease packing density. The subject method however permits high density packing of the silicon gate devices because small area source and drain regions and small area electrodes can be used. Because of the use of poly-silicon electrodes, the process allows the probing of the chip at intermediate stages in device fabrication. This allows the elimination of those chips which have not satisfied design limitations at an intermediate step in the fabrication process. In the process the source and drain regions and the electrodes are doped simultaneously in a diffusion step. In this diffusion process part of the source and drain regions are diffused through that portion of the poly-silicon contact extending over the source or drain region. In this manner ohmic contact is made between the electrodes and the underlying source or drain regions.

Design Limits When using Gold-Aluminum Bonds

Abstract: Gold-aluminum wire bonds form intermetallic phases with any elevated temperature treatment. Intermetallic formation alone does not cause bond failure. However, certain failure modes--open metallization in the bond area, lifted wire bonds after aging, and heel breaks after thermal cycling--may be related to intermetallic formation. Specific causes of these failure modes are discussed. These form the basis for the recommendations presented as design limits when using gold-aluminum wire bonds in circuits.

Thick film feed-through capacitor

Abstract: A feed-through capacitor deposited in a thick film on a flat, thin alumina substrate having an active circuit and a capacitor. The capacitor includes a bottom electrode of metallized film on the surface of the substrate, a layer of dielectric having a high-dielectric constant, and a top electrode of metallized film deposited on the dielectric. The bottom electrode film has a terminal portion for connection to ground reference potential and a lead film connected to the active circuit, the same extending around the edge of the substrate with the active circuit on the opposite side thereof. The top electrode film may be singular or multiple in nature, having an external terminal at one edge of each electrode and a lead film at the opposite edge connected to the active circuit, the same extending around the edge of the substrate with the active circuit on the opposite side of the substrate.

Oscillator with switchable filter control voltage input for rapidly switching to discrete frequency outputs

Abstract: A voltage controlled oscillator controllable to discrete frequency outputs, which outputs are applied to a phase detector through divider circuits and compared to a reference signal of the same frequency, is controlled to discrete frequency outputs by variable voltages or variable width pulses, proportional to the difference in phase between the two signals, from the phase detector which pulses are applied to the oscillator through loop filters. Each loop filter is an RC circuit which integrates the pulses and serves as a memory to retain a relatively constant voltage thereacross. Therefore, when a specific loop filter is switched into the circuit the voltage controlled oscillator is rapidly switched to a discrete frequency output proportional to the voltage stored in the loop filter.

Surface Reconstruction of Aluminum Metallization -- a New Potential Wearout Mechanism

Abstract: The surface of aluminum metallization on silicon devices can reconstruct with elevated temperature treatments due to the relief of compressive stresses induced by thermal expansion differences between aluminum and silicon. This reconstruction can cause reliability problems because of the development of thin regions in the metal. Also, in multilayer circuits, hillocks can punch through the oxide layer and cause electrical shorts. In this paper the surface reconstruction is categorized into two modes: high temperature--few cycles (device processing) and low temperature--many cycles (device operation). Mechanisms for each of these reconstruction modes are postulated and suggestions for reducing or eliminating this effect are made.

Modular television receiver

Abstract: The electrical components of a television receiver are assembled in a plurality of modules. Each module is coupled into the set by means of connectors so that it may be easily removed and replaced if required. Substantially all of the modules are assembled in a single chassis in the form of a drawer which can be moved to a forward position extending outside of the front of the television cabinet for easy access to each module.

Low temperature strengthening in niobium-hydrogen single crystals

Abstract: The mechanical behavior of high purity niobium and niobium-hydrogen single crystals at temperatures in the range 77° to 380°K was investigated. Thermally activated hardening by hydrogen in solution is appreciable at temperatures ≲150°K. However, hydride precipitation occurs at these temperatures, can be strain-induced during mechanical testing, and accounts for the largest part of the decrease in ductility in alloys with up to 720 at. ppm of hydrogen. The influence of hydrogen additions and the effects of purification on the low temperature flow stress of niobium demonstrate the large influence of interstitial solutes on the strength of bcc materials at low temperatures.

Multilayer metallization system

Abstract: There is disclosed a multilayer metallization system for use with medium scale and large scale integrated circuits in which titanium-platinum-gold beam leads are used in all of the metallization systems over the integrated circuit. A method is described in which successive metallization system are stacked one on top of another with passivation in between, in which the gold top portion of an underlying beam lead is contacted by a gold portion of the beam lead immediately thereabove. The method includes as an important step, removing the platinum and titanium of an overlying beam lead from an underlying passivation layer in the vicinity of a via hole in the passivation layer prior to the formation of this hole. This is followed by the formation of the via hole and the deposition of gold both over the platinum layer and into the via hole so as to contact the gold top portion of an underlying beam lead thereby forming a gold-gold interface. The method described permits the formation of multilayered Au-Pt-Ti beam lead structures which preserve the beam lead hermetic seal, which preserve the ohmic contact qualities of the beam lead structure, and which permit the stacking of the Au-Pt-Ti beam leads without the necessity of exotic processing or interfacing materials necessary to prevent peeling and poor ohmic contact.

Current limited battery pack

Abstract: A battery pack includes a resettable protection circuit for limiting the current to a load, which includes a normally nonconductive silicon controlled rectifier and a magnetic reed switch serially connected across a battery. When excessive load current develops, the silicon controlled rectifier is rendered conductive which in turn cuts off a regulating transistor or energizes a relay to prevent current flow to the load. The battery, magnetic reed switch, silicon controlled rectifier and regulating transistor or relay are encased in a sealed container to prevent sparks and arcing and allow usage in a hazardous atmosphere. The silicon controlled rectifier is reset, to allow continued usage of the battery, by actuating the reed switch with an externally supplied magnetic field. Actuation of the reed switch breaks the current path to the silicon controlled rectifier.

Noise blanker circuit including rate bias and rate shutoff circuitry and audio blanking

Abstract: A noise blanking circuit for decreasing the impulse noise in a receiver includes a noise channel which develops blanking pulses in response to impulse noise. The noise pulses are coupled to a stage in the signal path for blanking the signals coupled therethrough to eliminate the reproduction of impulse noise. A rate shutoff circuit includes first and second timing circuits which are responsive to the repetition rate of the blanking pulses, and the duration of a series of pulses respectively, to develop a rate shutoff signal which inhibits the coupling of the blanking pulses to the blanking circuit. A rate bias circuit, coupled to the rate shutoff circuit, is responsive to the rate shutoff signal to develop a rate bias signal to maintain the gain of the noise amplifiers at a desired level. An audio blanking circuit is coupled to the rate shutoff circuit and the receiver squelch circuit and is responsive to the blanking pulses exceeding a predetermined rate and duration to develop an audio blanking pulse for inhibiting operation of the receiver audio circuitry. The audio blanking circuit further includes timing circuitry which is responsive to the blanking pulses exceeding a predetermined rate and duration to inhibit development of the audio blanking signal when the rate shutoff function is operative.

Multi-function antenna coupler

Abstract: The antenna coupling circuit facilitates simultaneous reception and transmission of information carrying radio signals through a common antenna A single filter having a plurality of helical resonator sections forms the harmonic filter of the transmitter, the preselector of the receiver, and a duplexer for connecting both the transmitter and receiver to a single antenna A first plurality of the helical resonator sections are connected between the antenna and the input stage of a receiver which passes the band of frequencies to be received while reflecting the frequencies to be transmitted A second plurality of helical resonator sections are connected between the output of a transmitter and the antenna which passes the frequencies to be transmitted while reflecting the frequencies to be received The coupling between individual helical resonators is arranged to discriminate against frequencies higher than the passband All of the cells of the filter circuit are mechanically connected together to form an integral compact structure

Solid-state relay

Abstract: There is disclosed an improved solid-state relay comprising a C-MOS analog switch or transmission gate in which the change in input-output resistance for variations in the input signal is minimized by maintaining the substrate of the N-channel device at the same potential as that of the source of the N-channel device. The N-channel substrate provision source are maintained at the same potential by the privision of an additional P-MOS device located on the same integrated circuit chip in which the additional P-MOS device is rendered conductive during that period of time which the switch is in its conducting mode.