Agere Systems Inc.

Lsi Corporation

Lucent Technologies Inc.

Other

Avago Technologies General IP (singapore) Pte. Ltd.

Agere Syatems Inc.

Makeshwar Kothandaraman

John Christopher Kriz

Bernard Lee Morris

Dipankar Bhattacharya

Pankaj Kumar

Pramod Elamannu Parameswaran

Yehuda Smooha

Vani Deshpande

Bijit Thakorbhai Patel

Wayne E Werner

Jeffrey Jay Nagy

Carol Ann Huber

Stefan Allen Siegel

Antonio M Marques

Ashish V Shukla

Thaddeus John Gabara

David Arthur Rich

James D Chlipala

Duane J Loeper

Joseph E Simko

Peter J Nicholas

Paul K Hartley

Nirav Patel

Gregg R Harleman

Venu Babu Ummalaneni

Punkaj Kumar

An apparatus comprising a first stage and a second stage. The first stage may be configured to generate an intermediate signal having a first voltage in response to an input signal having a second voltage received from a pad. The second stage may be configured to generate a core voltage in response to the first voltage. The voltage received from the pad may operate at a voltage compliant with one or more published interface specifications.

Low power receiver for implementing a high voltage interface implemented with low voltage devices

An apparatus comprising a level shifter circuit and a control circuit. The level shifter circuit may be configured to generate a differential output in response to (i) a first differential input, (ii) a second differential input and (iii) a first supply. The level shifter circuit comprises a first pull down transistor pair operating with the first supply. The control circuit may be configured to generate the second differential input in response to (i) the first differential input and (ii) a second supply. The control circuit generally comprises a second pull down transistor pair operating with the second supply. The first supply has a higher voltage than the second supply.

Jitter reduction in high speed low core voltage level shifter

A comparison circuit for detecting impedance mismatch between pull-up and pull-down devices in a circuit to be monitored includes a comparator operative to receive first and second signals and to generate, as an output, a third signal indicative of a difference between the first and second signals. A first signal generator is operative to generate the first signal indicative of a difference between reference pull-up and pull-down currents that is scaled by a prescribed amount. The reference pull-up current is indicative of a current flowing through at least one corresponding pull-up transistor device in the circuit to be monitored. The pull-down reference current is indicative of a current flowing through at least one corresponding pull-down transistor device in the circuit to be monitored. A second signal generator connected with the second input of the comparator is operative to generate the second signal as a reference voltage defining a prescribed impedance mismatch threshold associated with the circuit to be monitored.

Impedance mismatch detection circuit

A reference circuit includes an NMOS transistor, a PMOS transistor and a bias circuit. The NMOS transistor includes a source connected with a first voltage supply and a gate adapted to receive a first bias signal. The PMOS transistor includes a source connected with a second voltage supply, a gate adapted to receive a second bias signal, and a drain connected with a drain of the NMOS transistor at an output of the reference circuit. The bias circuit generates the first and second bias signals. Magnitudes the first and second bias signals are configured to control a reference signal generated by the reference circuit such that when the reference signal is near a quiescent value of the reference signal, a current in the reference circuit is below a first level, and when the reference signal is outside of the prescribed limits, the current in the reference circuit increases nonlinearly.

High-voltage tolerant biasing arrangement using low-voltage devices

A compensation circuit for controlling a variation in output impedance of at least one buffer circuit includes a monitor circuit and a control circuit coupled with the monitor circuit. The monitor circuit includes a pull-up portion including at least one PMOS transistor and a pull-down portion comprising at least one NMOS transistor. The monitor circuit is configured to track an operation of an output stage of the buffer circuit and is operative to generate at least a first control signal indicative of a status of at least one characteristic of corresponding pull-up and pull-down portions in the output stage of the buffer circuit over variations in PVT conditions to which the buffer circuit may be subjected. The control circuit is operative to generate a set of digital control bits as a function of the first control signal. The set of digital control bits is operative to compensate the pull-up and pull-down portions in the output stage of the buffer circuit over prescribed variations in PVT conditions.

Hybrid impedance compensation in a buffer circuit

A voltage translator circuit () includes an input stage () adapted for receiving an input signal referenced to a first voltage supply (VDD core), a latch () adapted for connection to a second voltage supply (VDD) and operative to at least temporarily store a logic state of the input signal, and a voltage clamp () coupled between the input stage () and the latch (). The voltage clamp () is operative to set a maximum voltage across the latch () to a first prescribed level and to set a maximum voltage across the input stage to a second prescribed level. The voltage translator circuit () generates a first output signal (II) at a junction between the latch () and the voltage clamp (). The voltage translator circuit generates a second output signal () at a junction between the voltage clamp () and the input stage ().

Voltage level translator circuit

An apparatus comprising a first circuit, a second circuit, and a third circuit. The first circuit may be configured to generate a first control voltage and a second control voltage. The second circuit may be configured to generate a bias signal in response to the first control voltage and the second control voltage. The third circuit may be configured to generate a filtered signal in response to the bias signal. The filtered signal may be added to the first control voltage and the second control voltage to provide AC noise suppression when generating the bias signal.

AC noise suppression from a bias signal in high voltage supply/low voltage device

A differential buffer circuit having increased output voltage swing includes a differential input stage including at least first and second transistors, the first and second transistors being operative to receive first and second signals, respectively. The buffer circuit further includes a bias stage connected between the differential input stage and a first voltage source. The bias stage is operative to generate a quiescent current as a function of a third signal supplied to the bias stage. A load circuit is connected between a second voltage source and the differential input stage, first and second differential outputs of the buffer circuit being generated at a junction between the load circuit and the differential input stage. The load circuit includes first and second switching elements coupled with the first and second transistors, respectively. The first switching element is operative to electrically connect the first differential output to the second voltage source when the first transistor is turned off. The second switching element is operative to electrically connect the second differential output to the second voltage source when the second transistor is turned off.

Current-mode logic buffer with enhanced output swing

A voltage level translator circuit for translating an input signal referenced to a first voltage supply to an output signal referenced to a second voltage supply includes an input stage for receiving the input signal, the input stage including at least first and second nodes, a voltage at the second node being a logical complement of a voltage at the first node. A load circuit is coupled with the input stage, the load circuit being operative to at least temporarily store a signal at the first and/or second nodes which is indicative of a logical state of the input signal. An output stage connected with the second node is operative to generate an output signal which is indicative of a logical state of the input signal. The voltage level translator circuit further includes a compensation circuit connected with the output stage and operative to balance pull-up and pull-down propagation delays in the voltage level translator circuit as a function of a voltage at the first node.

Voltage level translator circuit for reducing jitter

In one embodiment, the invention is a method for modeling electrical behavior of a packaged module having multiple integrated circuits (ICs), such as a multi-chip module (MCM). The method includes: (a) identifying one or more pin groups in the module, wherein a pin group comprises two or more buffers connected together and to a package-external pin, and (b) generating one or more corresponding unified behavioral models for the one or more pin groups based on the characteristics of the buffers of the one or more pin groups. The behavioral models are part of an integrated behavioral model file in accordance with the I/O buffer information specification (IBIS) standard.

Input/output buffer information specification (IBIS) model generation for multi-chip modules (MCM) and similar devices

A compensation circuit for controlling a variation in output impedance of at least one buffer circuit includes a monitor circuit having a pull-up portion comprising at least one PMOS transistor and a pull-down portion comprising at least one NMOS transistor. The monitor circuit is configured to track an operation of an output stage in the buffer circuit and is operative to generate a first control signal indicating a status of at least one characteristic of corresponding pull-up and pull-down portions in the output stage over variations in PVT conditions to which the buffer circuit may be subjected. The compensation circuit further includes a control circuit generating first and second sets of digital control bits for compensating the pull-up and pull-down portions in the output stage over prescribed variations in PVT conditions. The second set of digital control bits is generated based at least on the first set of digital control bits and the first control signal.

Impedance compensation in a buffer circuit

A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of an IO receiver, and controllably generating a second bias voltage from an external voltage supplied through an IO pad to be within the upper tolerable limit of the operating voltage of the IO receiver. The method also includes deriving an output voltage from the first bias voltage during a normal condition and a tolerant condition, and deriving the output voltage from the second bias voltage during a failsafe condition. The tolerant condition is a mode of operation where the external voltage supplied through the IO pad varies from zero to a value higher than the supply voltage, and the failsafe condition is a mode of operation where the supply voltage is zero.

Interfacing between differing voltage level requirements in an integrated circuit system

A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of one or more constituent active circuit element(s) of an Input/Output (IO) core device of an integrated circuit (IC) to be interfaced with an IO pad, and controllably generating a second bias voltage from an external voltage supplied through the IO pad to be within the upper tolerable limit of the operating voltage of the one or more constituent active circuit element(s) of the IO core device to be interfaced with the IO pad. The method also includes controllably utilizing a control signal generated by the IO core to derive an output bias voltage from the first bias voltage during a driver mode of operation or the second bias voltage during a failsafe mode of operation and a tolerant mode of operation.

Bias voltage generation to protect input/output (IO) circuits during a failsafe operation and a tolerant operation

An ESD protection circuit includes a first voltage clamp, connected between a first voltage supply node and a second voltage supply node of the circuit, and a second voltage clamp, connected between the second voltage supply node and a voltage return of the circuit. The first voltage supply node is adapted to receive a first voltage which is greater than a prescribed gate oxide reliability potential of the circuit. The second voltage supply node is operative to receive a second voltage which is less than the first voltage. The first voltage clamp is operative to clamp the first voltage on the first voltage supply node to a first value during an ESD event between the first and second voltage supply nodes, and the second voltage clamp is operative to clamp the second voltage on the second voltage supply node to a second value during an ESD event between the second voltage supply node and the voltage return.

Electrostatic discharge protection circuit

Described embodiments provide for protecting from DC and transient over-voltage conditions an input/output ('I/O') buffer having first and second I/O transistors. The first I/O transistor is coupled to a first over-voltage protection circuit adapted to prevent an over-voltage condition on at least the first I/O transistor. The second I/O transistor is coupled to a second over-voltage protection circuit adapted to prevent an over-voltage condition on at least the second I/O transistor. First and second bias voltages are generated from an operating voltage of the buffer. A third bias voltage is generated from either i) the first bias voltage, or ii) an output signal voltage of the buffer and a fourth bias voltage is generated from either i) the second bias voltage, or ii) the output signal voltage of the buffer. The third and fourth bias voltages are provided to the first and second over-voltage protection circuits, respectively.

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Whitehall, PA, United States of America

Makeshwar Kothandaraman