Intel Corporation

Naveed Khan

Huimin Chen

Andrew M Volk

Ken Drottar

Duane G Quiet

Terry L Baucom

Amir Bashir

Tony L Lewis

Vishnu Balraj

Methods and apparatus for adaptive termination calibration of high-speed links. The methods provide a novel termination calibration obtained in conjunction with link training without using an external reference under which the termination resistors for transmitters (Rtx) and receivers (Rrx) are calibrated to the real channel impedance as part of the link training. The techniques may be implemented to optimize high-speed link operation in terms of impedance match between a channel's characteristic impedance and the source termination of a transmitter and the receiver termination of a receiver. During link training, both Rtx and Rrx are adjusted to maximize a peak amplitude of a received signal. Under one approach for bi-directional links, the Rrx for the receivers at both ends of the link are calibrated substantially concurrently. Under another approach, a calibrated Rrx for a first receiver is used for calibrating the Rrx for the second receiver. An Rtx may be set equal to an calibrated Rrx or may be calibrated separately.

Method of adaptive termination calibration

Disclosed are embodiments of methods and circuits to generate spread spectrum clocks.

Spread spectrum clock generator

Embodiments of the invention include apparatus with a level-up shifter including a comparator having a pair of cross coupled PFETs with sources coupled to an I/O power supply and gates coupled to each other's drain, and a differential pair of NFETs with sources coupled to ground and gates respectively coupled to a data input and an inverted data input; and first and second pull-up PFETs have sources coupled to a pull-up voltage and drains respectively coupled between the differential pair of NFETs and the pair of cross coupled PFETs. The cross coupled PFETs and differential pair of NFETs perform level translation of low swing logic levels at the data input to high swing logic levels on a drain of one of the cross-coupled PFETs, while first and second pull-up PFETs speed the level translation in response to the data input and the inverted data input.

High speed buffered level-up shifters

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Folsom, CA, United States of America

Naveed Khan