摘要:
Signal offset variation caused by transistor variation/mismatch in integrated circuits may be reduced. In one embodiment, a buffer circuit has variable-valued circuits elements. Offset variation measurements are made and the variable-valued circuit elements are calibrated to reduce the measured offset variation. In another embodiment, each amplifying stage of a multi-stage buffer provides variable gain. The total DC gain of the cascade is distributed unevenly across the stages, with more DC gain being provided by amplifier stages at the beginning of the cascade than at the end. An additional pre-amplifier stage can also be provided at the beginning of the cascade.
摘要:
Methods and apparatus are provided for selectively setting a CM voltage for a transceiver, reducing the effect of current mismatch, and generating a voltage step that can be used for receiver detection. A circuit of the invention can include voltage generator circuitry operable to generate a plurality of voltage signals of substantially different voltages. The circuit can also include multiplexer circuitry with voltage inputs coupled to the voltage signals. The multiplexer circuitry can be operable to select a reference signal from among the voltage inputs. In addition, the circuit can include operational amplifier (“op-amp”) circuitry with a first input coupled to the reference signal and a second input coupled to an output signal of the op-amp circuitry.
摘要:
An equalizer circuitry that includes an equalizer stage having a programmable current source is described. In one implementation, the programmable current source cancels voltage offset. Also, in one implementation, the programmable current source is programmable in user mode. Furthermore, in one implementation, the equalizer circuitry includes a plurality of equalizer stages including the equalizer stage having a programmable current source, where the equalizer stage having a programmable current source is a second equalizer stage in the plurality of equalizer stages. Also, in one implementation, the programmable current source includes a plurality of current sources coupled in parallel and a plurality of sets of control switches for controlling the plurality of current sources. Further, in one implementation, each current source of the plurality of current sources includes a transistor and each set of control switches of the plurality of sets of control switches is for controlling a respective current source and includes a pair of transistors for controlling the respective current source.
摘要:
Integrated circuits having transceivers capable of high-speed (e.g., 1 Gbps) operation without dedicated phase-locked loop circuitry are provided. One such integrated circuit device may include one or more transceivers capable of transmitting and receiving serial signals of approximately 1 Gbps or greater, and a multi-purpose phase-locked loop capable of providing a multi-phase clock signal to the one or more transceivers.
摘要:
Transceiver circuitry on a programmable logic device integrated circuit (“PLD”) is preferably provided in a plurality of identical or at least similar modules. Each module preferably includes a plurality of transceiver channels and a clock source unit. Clock distribution circuitry is provided for distributing the signal of a module's clock source to all of the transceiver channels in that module, and also selectively beyond that module to other modules.
摘要:
Various methods and structures related to clock distribution for flexible channel bonding are disclosed. One embodiment provides a clock network in physical media attachment (“PMA”) circuitry, a specific type or portion of system interconnect circuitry, arranged in pairs of channel groups. In one embodiment, clock generation circuitry blocks (“CGBs”) in each pair of channel groups receives outputs of multiple phased locked loop circuits (“PLLs”) which can be selectively utilized by the CGBs to generate PMA clock signals. In another embodiment, the CGBs can also select output of a clock data recovery (“CDR”)/transmit PLL circuitry block in one of the channels of a channel group of the pair of channel groups. In one embodiment, first groups of connection lines couple circuitry in a channel group pair such that a designated CGB in each channel group pair can provide clock signals to one or more of the channels in the channel group pair. In one embodiment, second groups of connection lines connect channels in one channel group pair to channels in other channel group pairs such that one or more channels across the channel group pairs can receive a clock signal generated by a CGB in a designated channel. These and other embodiments are described more fully in the disclosure.
摘要:
Disclosed are apparatus and methods for providing a serial interface with shared datapaths. The apparatus and methods share or re-use components from multiple lower-speed datapaths so as to efficiently provide a higher-speed datapath. In one embodiment, physical coding sublayer circuitry of the lower-speed datapaths is also used by the higher-speed datapath. In another embodiment, physical media access circuitry of the lower-speed data paths is also used by the higher-speed datapath. Other embodiments, aspects and features are also disclosed.
摘要:
One embodiment relates to an integrated circuit including a first strip of phase-locked loop (PLL) circuits on a first side of the integrated circuit, and a second strip of PLL circuits on a second side of the integrated circuit which is opposite from the first side. The PLL circuits in the first and second strips may be configured by programming the integrated circuit. Another embodiment relates to an integrated circuit including a plurality of phase-locked loop (PLL) circuits and a plurality of physical media attachment (PMA) triplet modules adjacent to the plurality of PLL circuits. Each PMA triplet module includes first, second and third channels. The first and third channels are arranged for use as receiving channels, and the second channel is arranged to be configurable as either a receiving channel or a clock multiplication unit. Other embodiments and features are also disclosed.
摘要:
Data signals transmitted over transmission media suffer from attenuation caused by the transmission media. Equalization circuitry may be provided to compensate for attenuation caused by the transmission media. Equalization circuitry may include multiple stages arranged in series to allow the frequency responses of the stages to aggregate together. Each stage may be programmable to insert a zero, which causes the frequency response of the stage to increase in magnitude by 20 dB/decade. The frequency location of the zero may also be programmable to allow each stage to contribute a certain amount of gain for a specific frequency. Each stage may also be programmable to determine the location of poles for reduction of high frequency noise and cross-talk cancellation.
摘要:
Data signals transmitted over transmission media suffer from attenuation caused by the transmission media. Equalization circuitry may be provided to compensate for attenuation caused by the transmission media. Equalization circuitry may include multiple stages arranged in series to allow the frequency responses of the stages to aggregate together. Each stage may be programmable to insert a zero, which causes the frequency response of the stage to increase in magnitude by 20 dB/decade. The frequency location of the zero may also be programmable to allow each stage to contribute a certain amount of gain for a specific frequency. Each stage may also be programmable to determine the location of poles for reduction of high frequency noise and cross-talk cancellation.