Integrated Device Technology, Inc.

Minhui Yan

Harmeet Bhugra

Chien-Chen Chen

Yongchou Lo

YuanHeng Lo

Pavan Kumar Alli

Chien Chen Chen

Integrated circuit devices may utilize automatic methods for adjusting the tail currents of current mode logic (CML) cells, which compensate for variations in process corners and thereby enable reliable operation of high performance circuits, such as frequency synthesizers. An integrated circuit may include a current mode logic (CML) circuit responsive to at least one input signal and a variable current source electrically coupled to the CML circuit. This variable current source can be configured to sink (or source) a first current from (or to) the CML circuit in response to a control signal. A control circuit may also be provided, which is configured to generate the control signal in response to a process corner indication signal. This process corner indication signal, which may be generated by a process corner detection circuit, preferably has a magnitude that estimates a relative speed of a process corner associated with the integrated circuit device.

Current mode logic circuits with automatic sink current adjustment

Oscillator circuits include a MEMs resonator, a variable impedance circuit (e.g., varistor) and an adjustable gain amplifier. The variable impedance circuit includes a first terminal electrically coupled to a first terminal of the MEMs resonator and the adjustable gain amplifier is electrically coupled to the variable impedance circuit. The adjustable gain amplifier may have an input terminal electrically coupled to the variable impedance circuit and a second terminal of the MEMs resonator may receive, as feedback, a signal derived from an output of the adjustable gain amplifier. A Q-factor control circuit may be provided, which is configured to drive the variable impedance circuit and the adjustable gain amplifier with first and second control signals, respectively, that cause an impedance of the variable impedance circuit and a gain of the adjustable gain amplifier to be relatively high during a start-up time interval and relatively low during a post start-up time interval.

Microelectromechanical-based oscillators having adjustable gain amplifiers therein that support Q-factor control

A frequency synthesizer includes a frequency generator configured to generate a periodic output signal in response to a periodic input signal and a temperature-dependent code. A temperature sensor is provided, which is configured to generate a temperature measurement signal in response to detecting a temperature of at least a portion of the frequency synthesizer. A control circuit is provided, which is configured to generate the temperature-dependent code in response to the temperature measurement signal and a plurality of clocks having unequal frequencies. The control circuit can include a cascaded arrangement of an oversampled data converter and a digital filter, which are sequentially responsive to first and second ones of the plurality of clocks during generation of the periodic output signal by the frequency generator.

MEMS-based frequency synthesizers having variable bandwidth temperature compensation

A frequency synthesizer is configured to generate a periodic output signal in response to a periodic input signal and a temperature-dependent frequency adjusting control signal. A temperature sensor is provided, which is configured to generate a temperature measurement signal in response to detecting a temperature of at least a portion of the frequency synthesizer. A control circuit is provided, which is configured to generate the temperature-dependent frequency adjusting control signal in response to the temperature measurement signal. This control circuit includes a cascaded arrangement of an oversampled data converter and a multi-stage digital filter, which is configured to generate a plurality of codes from respective ones of the digital filter stages, and a selection circuit, which is configured to use at least first and second ones of the plurality of codes in sequence during first and second consecutive time intervals to generate the temperature-dependent frequency adjusting control signal.

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San Jose, CA, United States of America

Minhui Yan