Abstract: CMOS logic circuitry powered by the clock signals wherein the addition of strategically placed diodes enables the circuits to behave in an adiabatic-like fashion.

Abstract: Low-power-dissipation CMOS oscillator circuits include inductors and capacitors forming tank circuitry. Cross-connected MOS devices provide positive feedback to replenish losses in the tank circuitry and thereby sustain oscillations. Each such oscillator circuit simultaneously generates complementary output sine-wave signals.

Abstract: Process, voltage, and temperature variations affect the noise generation of an output buffer. Controlling the switching speed of the buffer over these variations also controls the buffer noise, which may be due to ground bounce or other reasons. In one prior-art technique, the current flow behavior of a static circuit is used to control the rise and/or fall times of the output buffer. However, accounting for all possible variations in the factors that influence the switching speed is difficult with a static control circuit. In the inventive technique, the AC switching behavior of a scaled-down buffer that is driven by a periodic signal generates the control voltage. In this manner, the factors that influence buffer switching speed, including process, voltage, and temperature variations, may be more accurately accounted for.

Abstract: CMOS integrated circuit buffers typically use a dual-diode electrostatic discharge (ESD) protection technique. However, in some cases that technique inadvertently causes one of the diodes to conduct when a desired signal voltage is present on the bondpad, thereby clipping the desired signal. This occurs, for example, when an output buffer on an unpowered device is connected to an active bus, or when the input buffer of a 3 volt device receives a 5 volt signal. The present invention solves this problem by using a bipolar (e.g., pnp) protection transistor connected between the bondpad and a power supply bus (e.g., V.sub.SS). The base of the transistor is connected to the bondpad through a resistor that provides a time delay due to the R-C time constant that includes distributed capacitance. The time delay allows for a high conduction period, during which an ESD event is conducted through the bipolar transistor, thereby protecting the input or output buffer.

Abstract: Effective control of impedance values in integrated circuit applications is achieved with an integrated circuit transistor whose size is digitally controlled. The digitally controlled size is achieved, for example, with a parallel interconnection of MOS transistors. In one application, the digitally controlled transistor serves as a controlled impedance connected to an output terminal of an integrated circuit. In that application, a number of transistors are enabled with control signals, and the collection of enabled transistors is responsive to the input signal that normally is applied to a conventional transistor. In another application, where the digitally controlled transistor serves as a controlled impedance at the input of a circuit, only the control signals that enable transistors and thereby determine the effective developed impedance are employed.

Abstract: Effective control of impedance values in integrated circuit applications is achieved with an integrated circuit transistor whose size is digitally controlled. The digitally controlled size is achieved, for example, with a parallel interconnection of MOS transistors. In one application, the digitally controlled transistor serves as a controlled impedance connected to an output terminal of an integrated circuit. In that application, a number of transistors are enabled with control signals, and the collection of enabled transistors is responsive to the input signal that normally is applied to a conventional transistor. In another application, where the digitally controlled transistor serves as a controlled impedance at the input of a circuit, only the control signals that enable transistors and thereby determine the effective developed impedance are employed.

Abstract: Effective control of impedance values in integrated circuit applications is achieved with an integrated circuit transistor whose size is digitally controlled. The digitally controlled size is achieved, for example, with a parallel interconnection of MOS transistors. In one application, the digitally controlled transitor serves as a controlled impedance connected to an output terminal of an integrated circuit. In that application, a number of transistors are enabled with control signals, and the collection of enabled transistors is responsive to the input signal that normally is applied to a conventional transistor. In another application, where the digitally controlled transistor serves as a controlled impedance at the input of a circuit, only the control signals that enable transistors and thereby determine the effective developed impedance are employed.

Abstract: An output buffer provides for additional current sinking or sourcing capability by switching in an additional transistor when the output voltage passes a given level. This allows the output buffer to supply DC current to a load without requiring an excessively large AC drive capability, which could undesirably increase switching noise. In a typical embodiment, an inverter senses when the buffer output voltage reaches its switching threshold (approximately V.sub.DD /2), and turns on the additional transistor after a given delay. For example, a CMOS output buffer driving a TTL load may obtain additional current sinking capability by this technique. On-chip buffers (e.g., bus drivers and clock drivers) can also benefit from this technique.

Abstract: Disclosed is an output buffer which utilizes CMOS components to convert from CMOS to ECL voltages. The circuit includes a field effect transistor and an external resistor for providing both high and low voltages by applying to the gate of the field effect transistor appropriate control voltages.

Abstract: In certain circuits, it is desirable to match the electrical characteristics, (e.g., thresholds), of two (or more) MOS transistors. For example, in an ECL output buffer, a first transistor is a voltage reference, and a second transistor is an output buffer controlled by this voltage reference. However, the orientation of the transistors may affect their electrical characteristics. This may be due to the source/drain ion implantation step that occurs at an angle off the vertical, or other processing effects. The present invention provides symmetrical MOS transistors having characteristics that are independent of orientation. For example, a square gate layout provides both vertical and horizontal current components, thereby obtaining 90 degree rotational symmetry.

Abstract: An integrated circuit formed on a substrate has field effect transistors formed in relatively lightly doped (i.e., high resistivity) epitaxial layer, typically in a "tub" formed therein. Operating current for the transistors is provided at least in part through a metallic layer on the back side of the substrate. Surprisingly, the conductivity is sufficiently high through the epitaxial layer and the substrate that the number of power supply bondpads on the front side may be reduced, or eliminated entirely in some cases. In addition, a reduction in power supply lead inductance is obtained, reducing ringing and ground bounce problems.

Abstract: An integrated circuit has output buffers whose switching rise and/or fall times are controlled to compensate for process speed and other variations. Therefore, an integrated circuit fabricated by a "fast" process does not generate excessive noise, while integrated circuits fabricated by a "slow" process still obtain adequate speed. A control voltage generated by an on-chip voltage divider network is applied to the gate of a control transistor to provide the compensation.