Abstract: A memory module is formed of multiple memory chips and an optical interface chip fixed on a substrate. The chips are interconnected by proximity communication (PxC) in which each chip includes transmitting and receiving elements, such as electrical pads which form capacitively coupled links when the chips are placed together with their pads facing each other. The PxC links may be directly between the chips or through an intermediate passive bridge chip. The interface chip is coupled to an external optical channel and includes converters between optical and electrical signals, control circuitry, buffers, and PxC elements for communicating with the memory chips. The array of memories may be a linear or two-dimensional array around the interface chip forming a redundant PxC network, optionally with redundant PxC connections. Multiple rectangular memory chips may present their narrow sides to the interface chip to maximize bandwidth.

Abstract: A system that fabricates a semiconductor chip. The system places patterns for components which require fine line-widths within a high resolution region of a reticle, wherein the high resolution region provides sharp focus for a given wavelength of light used by the lithography system. At the same time, the system places patterns for components which do not require fine line-widths outside of the high-resolution region of the reticle, thereby utilizing the region outside of the high-resolution region of the reticle instead of avoiding the region. Note that the coarseness for components placed outside of the high resolution region of the reticle is increased to compensate for the loss of optical focus outside of the high resolution region.

Abstract: A capacitively and conductively coupled multiplexer (C3mux) circuit is described. This C3mux circuit includes a set of nonlinear coupling capacitors, such as metal-oxide-semiconductor (MOS) transistors, that can multiplex multiple input signals while minimizing the parasitic capacitance penalty associated with the ‘off’ paths. In particular, the capacitance of a given MOS transistor depends on whether its channel is present or absent. Furthermore, this channel is formed based on whether the gate-to-source and drain voltages for the MOS transistor are greater than the MOS transistor's threshold voltage. Note that the capacitance of the MOS transistors in the C3mux circuit is low for the unselected inputs. Consequently, the parasitic loading and the delay increase slowly as a function of the number of inputs. Moreover, the conductive feedback can be used to maintain a DC level of the input signals.

Abstract: Offset voltages developed on floating nodes on inputs to high-performance amplifiers that are DC isolated from the data signals input to amplifiers are cancelled by connecting a highly resistive element between the input node and a predetermined potential, particularly useful in proximity communication systems in which two chips are connected through capacitive or inductive coupling circuits formed jointly in the two chips. The resistive element may be an off MOS transistor connected between the node and a desired bias voltage or a MOS transistor with its gate and drain connected to the potential. Multiple bias voltages may be distributed to all receivers and locally selected by a multiplexer for application to one or two input nodes of the receiver. The receiver output can also serve as a predetermined potential when the resistive element has a long time constant compared to the data rate or the resistive element is non-linear.

Abstract: Embodiments of an integrated circuit are described. This integrated circuit includes a clock-generator circuit configured to provide a clock signal and an optical clock path coupled to the clock-generator circuit. Note that the optical clock path is configured to distribute optical signals corresponding to the clock signal. Furthermore, note that a given optical signal has a phase which is different than phases of the other optical signals.

Abstract: One embodiment of the present invention provides a system that facilitates high-bandwidth communication using a flexible bridge. This system includes a chip with an active face upon which active circuitry and signal pads reside, and a second component with a surface upon which active circuitry and/or signal pads reside. A flexible bridge provides high-bandwidth communication between the active face of the chip and the surface of the second component. This flexible bridge provides a flexible connection that allows the chip to be moved with six degrees of freedom relative to the second component without affecting communication between the chip and the second component. Hence, the flexible bridge allows the chip and the second component to communicate without requiring precise alignment between the chip and the second component.

Abstract: One embodiment of the present invention provides a system that facilitates biasing receiver circuits within an integrated circuit. During operation, the system provides n receiver circuits within the integrated circuit to be biased. Next, the system provides n+m communication channels between n drivers and n receivers, wherein m is a number of additional communication channels, and wherein m>0. Then, the system couples the n+m communication channels to the n drivers, wherein each driver is selectively coupled to m+1 communication channels. The system also couples the n+m communication channels to the n receivers, wherein each receiver is selectively coupled to m+1 communication channels. In this way, at any given time n of the communication channels are active and m of the communication channels are inactive. Finally, the system refreshes inactive m communication channels' biases while the m inactive communication channels are not communicating signals.

Abstract: In a proximity communication system, transmit elements on one chip are aligned with receive elements on a second chip juxtaposed with the first chip. However, if the elements are misaligned, either statically or dynamically, the coupling between chips is degraded. The misalignment may be compensated by controllably degrading performance of the system. For example, the transmit signal strength may be increased. The bit period or the time period for biasing each bit may be increased, thereby decreasing the bandwidth. Multiple coupling elements, such as capacitors, may be ganged together, thereby decreasing the number of channels. The granularity of symbols, such as images, may be increased by decreasing the number of bits per symbol. Multiple coupling elements, such as capacitors, may be ganged together, thereby decreasing the number of channels.

Abstract: Embodiments of an integrated circuit that includes a debug circuit are described. This debug circuit is configured to test an asynchronous circuit by performing analog measurements on asynchronous signals associated with the asynchronous circuit, and includes a triggering module configured to gate the debug circuit based on one or more of the asynchronous signals. This triggering module has a continuous mode of operation and a single-shot mode of operation. A timing module within the debug circuit has a timing range exceeding a pre-determined value, and is configured to provide signals corresponding to a first time base or signals corresponding to a second time base. Furthermore, control logic within the debug circuit is configured to select a mode of operation and a given time base for the debug circuit, which is either the first time base or the second time base.

Abstract: A system that facilitates high-speed data transfer between integrated circuit chips. The system contains a first integrated circuit chip, which includes a capacitive receiver and an electrical-to-optical transceiver. The capacitive receiver receives a capacitively coupled voltage signal transmitted from a corresponding capacitive transmitter located on a second integrated circuit chip and converts the capacitively coupled voltage signal into an electrical signal. The electrical-to-optical transceiver converts the electrical signal to an optical signal and transmits the optical signal to an optical device through optical coupling.

Abstract: One embodiment of the present invention provides a system that facilitates high-bandwidth communication using a flexible bridge. This system includes a chip with an active face upon which active circuitry and signal pads reside, and a second component with a surface upon which active circuitry and/or signal pads reside. A flexible bridge provides high-bandwidth communication between the active face of the chip and the surface of the second component. This flexible bridge provides a flexible connection that allows the chip to be moved with six degrees of freedom relative to the second component without affecting communication between the chip and the second component. Hence, the flexible bridge allows the chip and the second component to communicate without requiring precise alignment between the chip and the second component.

Abstract: An active resistor and its use in a negative feedback amplifier allow wide voltage swings on the input and output signals. One embodiment includes parallel pass-gate MOS transistors of opposite conductivity types connected between the input and output nodes. Bootstrapping transistors are connected between the gates of the pass-gate transistors and respective bias voltages. Coupling capacitors are connected between the gates and the output node. Additional coupling capacitors may be connected between the gates and the input node to make the resistor symmetric. In other embodiments, only one pass-gate transistor is used.

Abstract: One embodiment of the present invention provides a system that facilitates high-bandwidth communication using a flexible bridge. This system includes a chip with an active face upon which active circuitry and signal pads reside, and a second component with a surface upon which active circuitry and/or signal pads reside. A flexible bridge provides high-bandwidth communication between the active face of the chip and the surface of the second component. By matching the wire line size in the flexible bridge to the size of circuits and/or signal pads on the chip and on the second component, the system allows signals to be sent between the circuits on the chip and the second component without having to change the scale of the interconnect, thereby alleviating wireability and bandwidth limitations of conventional chip packaging technologies.

Abstract: Embodiments of an integrated circuit are described. This integrated circuit includes: a clock-generator circuit configured to provide a clock signal; an optical clock path coupled to the clock-generator circuit; and a latch coupled to the optical clock path. This optical clock path is configured to distribute an optical signal corresponding to the clock signal. Furthermore, the optical clock path is configured to optically set a skew value for the optical signal, and is configured to selectively gate distribution of the optical signal to the latch based on activity of the latch. Note that the selective gating is performed optically.

Abstract: A system that includes a first buffer and a second buffer, wherein the first buffer and the second buffer are connected to the same input, wherein a size of the first buffer is defined by a distance of the first buffer from the input and a transfer rate of data, wherein a size of the second buffer is defined by a distance of the second buffer from the input and the transfer rate of data, and wherein the distance between the first buffer and the input is different from the distance between the second buffer and the input.

Abstract: A system that includes a first buffer and a second buffer, wherein the first buffer and the second buffer are connected to the same input, wherein a size of the first buffer is defined by a distance of the first buffer from the input and a transfer rate of data, wherein a size of the second buffer is defined by a distance of the second buffer from the input and the transfer rate of data, and wherein the distance between the first buffer and the input is different from the distance between the second buffer and the input.

Abstract: An active resistor and its use in a negative feedback amplifier allow wide voltage swings on the input and output signals. One embodiment includes parallel pass-gate MOS transistors of opposite conductivity types connected between the input and output nodes. Bootstrapping transistors are connected between the gates of the pass-gate transistors and respective bias voltages. Coupling capacitors are connected between the gates and the output node. Additional coupling capacitors may be connected between the gates and the input node to make the resistor symmetric. In other embodiments, only one pass-gate transistor is used.

Abstract: A system of protecting a proximity communication system against electrostatic discharge (ESD). The proximity communication system includes two chips, each having an array of electrical pads at its surface and covered by a thin dielectric layer such that capacitive coupling circuits are formed between the chips when they are joined together. In at least one of the chips, an additional protection pad is formed away from the array, and heavy protection circuitry is connected to it. Its surface is exposed through the dielectric surface over it such that, when an ESD aggressor approaches, the discharge occurs to the protection pad.

Abstract: A system that dynamically refreshes the inputs of a differential receiver. During operation, while a differential transmitter is not transmitting data, the system applies substantially equal voltages to the outputs of the differential transmitter so that the differential voltage on the outputs of the differential transmitter is substantially zero. The system then refreshes the inputs of an associated differential receiver by applying substantially equal voltages to the inputs of the differential receiver so that the differential voltage on the inputs of the differential receiver is substantially zero. The differential transmitter is coupled to the differential receiver through a DC blocking mechanism, which prevents a DC voltage on the differential transmitter from reaching the differential receiver.

Abstract: A memory module is formed of multiple memory chips and an optical interface chip fixed on a substrate. The chips are interconnected by proximity communication (PxC) in which each chip includes transmitting and receiving elements, such as electrical pads which form capacitively coupled links when the chips are placed together with their pads facing each other. The PxC links may be directly between the chips or through an intermediate passive bridge chip. The interface chip is coupled to an external optical channel and includes converters between optical and electrical signals, control circuitry, buffers, and PxC elements for communicating with the memory chips. The array of memories may be a linear or two-dimensional array around the interface chip forming a redundant PxC network, optionally with redundant PxC connections. Multiple rectangular memory chips may present their narrow sides to the interface chip to maximize bandwidth.