Rambus Inc.

Gundlapalli Shanmukha Srinivas

Amir Amirkhany

Chaofeng Huang

Hajee Mohammed Shuaeb Fazeel

Srinivasaraman Chandrasekaran

A Phase Interpolator (PI) may be employed as a precisely-controlled delay element in a transmit path, for example in clock forwarded serial links. Methods and circuits are disclosed for estimating a delay needed to correct duty-cycle/and or phase errors of the received clock. These corrections or delta values may be transmitted back to the transmitter side, preferably expressed directly in terms of PI phase codes, for convenient adjustment in the transmitter clock circuitry. Various techniques also are disclosed for measuring and mitigating the effects on PI integral non-linearity.

Open-loop correction of duty-cycle error and quadrature phase error

Disclosed are methods and circuits that support different on-die termination (ODT) schemes for a plurality of signaling schemes using a relatively small number of external calibration pads. These methods and circuits develop control signals for calibrating any of multiple termination schemes that might be used by associated communication circuits. The ODT control circuits, entirely or predominantly instantiated on-die, share circuit resources employed in support of the different termination schemes to save die area.

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Bengaluru, India

Gundlapalli Shanmukha Srinivas