Xilinx, Inc.

Arvind R Bomdica

Xiaobao Wang

Balakrishna Jayadev

David S Smith

Amitava Majumdar

Richard William Swanson

Samudyatha Suryanarayana

Andrew Tabalujan

Vipul Dutt Badoni

Vinit Shah

Burton M Leary

Apparatus and associated methods relate to an I/O bank impedance calibration circuit having (a) a replica master resistor coupled to an external precision resistor, and (b) a control circuit configured to calibrate an output impedance of the master resistor to generate a calibrated code to control a replica slave resistor in each bank. In an illustrative example, a signal applied to the replica master resistor may be compared against a programmable reference signal. The control circuit may generate the calibrated code, in response to the comparison result, to calibrate the output impedance of the replica master resistor. By implementing the replica master resistor and the replica slave resistor, impedances of a large number of IOs or banks may be calibrated by the impedance calibration circuit using a single one reference pin.

Calibration of transmitter output impedance and receiver termination impedance using a single reference pin

Methods and apparatus relate to a 1-to-2 memory interface deserializer circuit that, in a training mode, independently positions even and odd strobes in respective even and odd data windows. In an illustrative example, the deserializer circuit may receive a data signal that encodes even and odd data streams on the rising (even) and falling (odd) edges of a strobe clock signal. During a training mode, the deserializer circuit may independently determine, for example, an optimal temporal delay for each of the even strobe and the odd strobe. Adjustable delay lines dedicated to each of the even and odd strobe signals may simultaneously detect valid data window edges to permit determination of a desired delay to optimally position the strobe signals. Various embodiments may advantageously reduce jitter associated with asymmetric strobe and/or data signals to achieve a predetermined specification (e.g., timing margins) within the corresponding data windows.

Training and tracking of DDR memory interface strobe timing

An apparatus includes a plurality of adjustable driver circuits having output nodes coupled to a signal line. Each adjustable driver circuit is configured to drive the signal line with a portion of a total drive strength indicated by a value of a binary control signal. The apparatus also includes a delay circuit configured to delay the binary control signal provided to each adjustable driver circuit by a respective time period unique to the adjustable driver circuit.

Strength-adjustable driver

An integrated circuit enabling the communication of data is described. The integrated circuit comprises an input/output port; a plurality of data converter circuits; and programmable interconnect circuits coupled between the input/output port and the plurality of data converter circuits, the programmable interconnect circuits enabling a connection of the plurality of data converter circuits to the input/output port of the integrated circuit. A method of enabling the communication of data in an integrated circuit is also described.

Circuits for and methods of testing the operation of an input/output port

A programmable receiver implemented in an integrated circuit device is described. The programmable receiver comprises a pre-amplifier circuit coupled to receive an input signal, the pre-amplifier circuit having a programmable current source; and an amplifier circuit coupled to receive an output of the pre-amplifier circuit; wherein the programmable current source is coupled to receive a control signal to enable the receiver to be switched between a high performance mode and a low performance mode. A method of implementing a programmable receiver in an integrated circuit is also described.

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Palo Alto, CA, United States of America

Arvind R Bomdica