International Business Machines Corporation

Other

Motorola Corporation

Fahd Hinedi

Moises Cases

Satyajit Dutta

Robert H Dennard

Lakshmikant Mamileti

James Nolan Hardage

A bus-clock-speed-independent apparatus and method of wrap input/output (I/O) testing of an I/O interface is provided. Launch data is launched in response to a launch clock. A capture clock is derived from the launch clock by delaying the launch clock through a programmable delay. Launch data is wrapped through the I/O interface buffers and captured in response to the capture clock. A initial value of the programmable delay is selected and successively increased or decreased until the launch data is just captured, or just fails to be captured, respectively. The value of the programmable delay when this occurs provides a measure of the limiting speed of the I/O interface.

Apparatus for bus frequency independent wrap I/O testing and method therefor

Series-connected stacked PFETS are employed in an off-chip driver output stage. When the output driver is enabled, the gate of the PFET transistor directly connected to the output is biased by a latch at a voltage level of either one threshold voltage above ground or one threshold voltage below the power supply, depending on the data signal. This provides overvoltage protection even for overshoots and undershoots of one threshold voltage or less, and provides overvoltage protection below the threshold voltages required to activate conventional overvoltage protection devices. Tight tolerances for maximum gate voltages may thus be achieved, and smaller devices having thinner gate oxides utilized in the off-chip drivers of a processor or other device.

Stacked PFET off-chip driver with a latch bias generator for overvoltage

Circuit and method aspects are provided for voltage level translation circuit for an output driver. In a circuit aspect, a circuit includes an input mechanism for receiving an internal data signal of a first predetermined voltage range, at least two stacked transistors coupled to the input mechanism, and a bias generator coupled to the input mechanism and the at least two stacked transistors, the bias generator ensuring that the at least two stacked transistors operate below a predetermined maximum device voltage. The circuit further includes an output mechanism coupled to the at least two stacked transistors, the output mechanism providing an external signal of a second predetermined voltage range.

Voltage level translation for an output driver system with a bias

An output driver which maintains over voltage protection on individual circuit elements, providing either a level shifted logic high or a floating-state on its output. The output driver includes a latch driven by a set circuit and a reset circuit. The latch output drives an output stage which produces a level shifted logic high when the latch is set and a floating-state when the latch is reset. Minimal voltage is applied across individual circuit elements by supplying power in concurrent incremental voltage levels to the output driver.

Voltage protected level shifting of chip driver

Circuit and method aspects for translating acceptable voltage levels from an external device to acceptable voltage levels of an internal device are provided. These aspects include coupling an input receiver between the external device and the internal device, the input receiver including a clamp device, and coupling a bias generator to the input receiver at the clamp device, wherein the bias generator ensures proper translation of a high level input signal from the external device by the input receiver. The bias generator further ensures that a predetermined maximum device voltage of the clamp device is not exceeded.

Circuit and method for voltage level translation utilizing a bias

With first semiconductor circuitry, a first signal is received having a first voltage between a voltage A and a voltage B. With second semiconductor circuitry, a second signal is output having a second voltage between a voltage C and a voltage D in response to the first signal. C is greater than A, and D is greater than B.

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Austin, TX, United States of America

Fahd Hinedi