Abstract: An RF communications system includes a transmit node for transmitting an RF information signal and a receive node for receiving the transmitted RF information signal. The receive node includes a passive mixer coupled to an amplifier for producing an IF or baseband differential mixer output signal as a function of a LO drive signal. The passive mixer having a first plurality of transistors of a first polarity type arranged in a ring configuration and a second plurality of transistors of a second polarity type, wherein each of second plurality of transistors is coupled to one of said first plurality of transistors.

Abstract: An electrically and thermally enhanced die-up tape substrate ball grid array (BGA) package and die-up plastic substrate BGA package are described. A substrate that has a first surface and a second surface is provided. The stiffener has a first surface and a second surface. The second stiffener surface is attached to the first substrate surface. An IC die has a first surface and a second surface. The first IC die surface is mounted to the first stiffener surface. A plurality of solder balls is attached to the second substrate surface. In one aspect, a heat spreader is mounted to the second IC die surface. In another aspect, the stiffener is coupled to ground to act as a ground plane. In another aspect, the substrate has a window opening that exposes a portion of the second stiffener surface. The exposed portion of the second stiffener surface is configured to be coupled to a printed circuit board (PCB). In another aspect, a metal ring is attached to the first stiffener surface.

Abstract: A data switch for network communications includes a first data port interface which supports at least one data port which transmits and receives data. A second data port interface is also provided supporting at least one data port transmitting and receiving data. A CPU interface is provided, with the CPU interface configured to communicate with a CPU. A common memory is provided, and communicates with the first data port interface and the second data port interface. A memory management unit is provided, and communicates data from the first data port interface and the second data port interface and an common memory. At least two sets of communication channels are provided, with each of the communication channels communicating data and messaging information between the first data port interface, the second data port interface, and the memory management unit.

Abstract: A mechanism and method for redefining an application specific integrated circuit's I/O bus structure in real-time. The mechanism includes an address map block, a state machine block, and a bus arbitration block. At initialization, the address map is configured to divide the address space into regions and type of bus structure. When an I/O access is requested by a client (e.g., CPU, DMA controller, etc.), the request is mapped into a region and type of bus structure by the address map block. The region and type of bus structure is used by the state machine. The state machine determines the syntax and protocol for the region and type of bus. The state machine signals the bus arbitration block to grant I/O bus ownership when it is available. Once ownership is granted, I/O bus pins are defined and access is granted.

Abstract: An ADSL transceiver chip is provided that includes an analog front-end and a digital signal processor (DSP) integrated on the same substrate. A line driver for the ADSL transceiver can be located on a separate substrate. In embodiments of the invention, the transceiver chip is implemented in a CMOS process. For example, the process could be a low voltage CMOS process. It is highly advantageous to build the analog front-end and the DSP on a single integrated IC because it allows for reduced manufacturing part count, reduced assembly time and cost. Furthermore, the line driver substrate can require a high voltage semiconductor process (e.g. 18 volts peak-to-peak) in some applications, because of the need for adequate voltage to drive the ADSL line. Whereas, the analog front-end and the DSP do not need the such a high-voltage process as required for the by the line driver 102. For example, the analog front-end and DSP can operate with 3.3 v or 5.

Abstract: A mixer for a radio transceiver includes a commutating mixer switch having a first differential input port coupled to a DC offset cancellation path. The first differential input port of the mixer switch includes a first terminal coupled to a first end of a first resistor and a second terminal coupled to a first end of a second resistor. Second ends of the first and second resistors are configured to receive a differential input signal. The DC offset cancellation path may provide a resistively coupled DC calibration signal for reducing the magnitude of DC offsets that may be present at the input of the mixer switch. The concept can be used for either image or non-image reject mixers.

Abstract: A virtual tester that simulates automatic test equipment (ATE). A translator converts program code of the ATE to pattern information and timing information. The virtual tester tests a software representation of a circuit, based on the program code of the ATE. The virtual tester uses the pattern information and/or the timing information to test the software representation of the circuit.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, and graphics input. The chip includes a single polyphase filter that preferably provides both anti-flutter filtering and scaling of graphics. Anti-flutter filtering may help reduce display flicker due to the interlaced nature of television displays. The scaling of graphics may be used to convert the normally square pixel aspect ratio of graphics to the normally rectangular pixel aspect ratio of video.

Abstract: A data switch for network communications includes a first data port interface which supports at least one data port which transmits and receives data. A second data port interface is also provided supporting at least one data port transmitting and receiving data. A CPU interface is provided, with the CPU interface configured to communicate with a CPU. A common memory is provided, and communicates with the first data port interface and the second data port interface. A memory management unit is provided, and communicates data from the first data port interface and the second data port interface and an common memory. A communication channel is provided, with the communication channel communicating data and messaging information between the first data port interface, the second data port interface, and the memory management unit.

Abstract: An analog open-loop voltage controlled oscillator (VCO) calibration circuit and method for selecting the frequency of the VCO for a phase locked loop (PLL). A frequency divider module produces a 50% duty cycle divided local oscillation and a 50% duty cycle divided reference signal, wherein the divided signals are substantially equal. A period-to-voltage conversion module converts the divided local oscillation signal and the divided reference signal to voltages proportional to the divided signals. A comparator module produces a frequency adjustment signal based on a comparison of the proportional voltages and couples the frequency adjustment signal to a logic module which produces a frequency compensation signal based on the frequency adjustment signal. The frequency compensation signal functions to adjust the configuration of switched capacitors in a capacitor bank, coupled to the VCO tuned circuit, until the divided local oscillation signal is substantially equal to the divided reference signal.

Abstract: A receiver includes clock termination circuitry that is capable of applying either a terminating impedance or a high impedance to a transmission path that carries a clock signal. When multiple of these receivers are used to service data links that share a clock signal, one of the clock termination circuits applies the terminating impedance to the transmission path that carries the clock signal while the other clock termination circuit(s) applies a high impedance to the transmission path. The receiver also includes a plurality of high rate serial bit stream buffers and a clock signal buffer along with the clock termination circuitry. In other embodiments, the receiver includes a deserializer and may include a controller. The receiver may service a dual link Digital Visual Interface.

Abstract: An integrated circuit includes a core circuit and a buffer circuit. The buffer circuit includes a plurality of input buffers and a plurality of output buffers that service a plurality of voltage domains on a single set of input/output lines. These voltage domains are controllable to service multiple voltage levels, consistent with various interface standards. In one construction, the core circuit operates at 1.2 volts and the buffer circuit supports both a 1.2 volts interface standard and a 3.3 volts interface standard.

Abstract: A method can allow a system to selectively control increasing of a bias source in a reference buffer or decreasing impedance looking into a output of the reference buffer for a temporary or selective time period, which can result in an increased overall efficiency of the system. The method can include at least the following steps. A first input signal is received at an input of a reference buffer. A second input signal is received from a load at an output of the reference buffer. A value of a bias source coupled to the output of the reference buffer is modulated, such that a spike of a signal at the output of the reference buffer caused by the second input signal is maintained below a threshold value. Alternatively, an impedance looking into the output of the reference buffer is modulated, such that a spike of a signal at the output of the reference buffer caused by the second input signal is maintained below a threshold value.

Abstract: A novel approach of repeated adaptation is provided that can be applied to either one or both of channel estimation and/or equalization. From an incoming data packet that includes data and a training sequence, a modified data packet is generated that includes the data, the training sequence, and at least one additional copy of the training sequence. From the format of this modified data packet, the same training sequence can be used over and over again a desired number of times to perform channel estimation and subsequent calculation of equalizer tap coefficients. Alternatively, the same training sequence can be used over and over again a desired number of times to converge the equalizer coefficient taps directly without doing any preliminary channel estimation. Generally, either of these approaches can be characterized as a cyclic adaptation operation that provides improved performance without incurring any reduction in throughput of the communication channel.

Abstract: A network switch for network communications includes at least one first data port interface, wherein the a least one first data port interface supports a plurality of first data ports transmitting and receiving data at a first data rate. At least one second data port interface is provided, wherein the at least one second data port interface supports a plurality of second data ports transmitting and receiving data at a second data rate. A flow control unit is provided, wherein at least one of the first data ports and at least one of the second data ports are linked together with a plurality of ports on a second network switch forming a trunk group that is configured by the flow control unit to statistically distribute a data load transmitted across the trunk group.

Abstract: A method of handling data packets in a series of network switches is disclosed. An incoming data packet is received at a data port of a first switch of the series of network switches and a stack tag is resolved from a header of the incoming data packet. It is then determinined whether an incoming data packet is a unicast packet, a multicast packet or an IP multicast packet; and the address resolution lookup and layer three IP lookup tables are searched to find an egress port for the incoming data packet. The packet header is modified and the packet is forwarded to at least a second switch of the series of network switches, on a stacked connection operating at a first data rate, based on the stack tag and the egress port. The header is later remodified when the egress port is one of a series of data ports of a particular switch of the series of switches.

Abstract: A precision tunable VCO includes a bias transistor, a first inductor, a second inductor, a first input transistor, a second input transistor, a first capacitor, a second capacitor, a first precision tune capacitor circuit, and a second precision tune capacitor circuit. The bias transistor, the first and second inductors, the first and second input transistors, and the first and second capacitors are operably coupled to produce a differential output oscillation. The first precision tune capacitor circuit is operably coupled to the first leg of the differential output oscillation, wherein the first precision tune capacitor circuit provides a first precision capacitance value based on a calibration signal.

Abstract: Method and circuitry for performing a line loop back test includes a receiver, a deserializer, and a low speed parallel loop back data multiplexer selects either the low speed parallel data from the deserializer when in loop back mode or low speed parallel input data when in normal mode. The deserializer produces a low speed clock output signal that is fed to a low speed loop back reference clock multiplexer and also to a low speed loop back clock multiplexer. Both the loop back reference clock multiplexer and the loop back clock multiplexer select the low speed clock output signal from the deserializer when in line loop back mode. A clock multiplying unit converts the output of the low speed loop back reference clock multiplexer into a high speed clock signal. The serializer generates the high speed serial transmitter data in synchronization with the high speed clock signal received from a clock multiplying unit.

Abstract: A content addressable memory cell (10) includes a circuit (20) operating from a predetermined supply voltage (VDD) for storing a first bit of data at a first point (35) and a second bit of complementary data at a second point (36). A first transistor (40) comprising a first gate (42) is switchable to first and second states in response to predetermined relationships between the first and second bits and third and fourth test bits transmitted on first and second lines (14 and 16). Second and third transistors (50, 60) comprise gates (52, 62) coupled to the first line (14) and second line (16) and comprise circuit paths (54, 56, 64, 66) coupling the first and second points to the first gate.

Abstract: A method for designing multi-layer electronic circuits includes defining a plurality of circuit blocks in terms of physical boundaries, the plurality of circuit blocks including a first circuit block with at least one port for connecting to a portion of inter-block routing having conducting material external to the first circuit block. The method further provides protective routing for the at least one port of the first circuit block in a region between the block and the inter-block routing, wherein circuitry within the first circuit connected to the at least one port is not in-circuit with the conducting material of the inter-block routing during processing steps involving the conducting material. The protective routing is a conducting layer which is higher in the multi-layer structure than the highest conducting layer used for routing the net containing the at least one port for inter-block routing.