Analog Devices,inc.

Xuesong Jiang

A synthesizable clock doubler is disclosed. The clock doubler is implemented using unique combination of logic cells from a standard cell library. At the core of the clock doubler is a high-frequency ring oscillator that generates timing information for clock measurements. Replica ring oscillators are used to generate programmable delays for the correction of the output clock imperfection, such as cycle-to-cycle variation and duty cycle of the doubled clock.

Clock doubler with correction for output clock cycle and clock duty cycle

Apparatus and methods for oscillator interface circuits with quadrature clock generation and phase correction are disclosed. In certain embodiments, a clock system includes an external oscillator that provides a differential input clock signal, and a semiconductor die that includes a first pin that receives a non-inverted component of the differential input clock signal and a second pin that receives an inverted component of the differential input clock signal. The semiconductor die further includes an oscillator interface circuit that includes a first controllable resistor and a first controllable capacitor connected in series between the first pin and the second pin, and a second controllable resistor and a second controllable capacitor connected in series between the second pin and the first pin.

Apparatus and methods for local oscillator interface circuits with quadrature clock generation and phase correction

Virtual shielding is used to reduce the sources/origins of latchup and switching noise in a synchronous switching regulator. The regulator power stage may be split into two half stages. The ground bond wires of the half power stages may be positioned on opposite sides of the layout to substantially eliminate coupling between the ground bond wires. The power supply bond wire in one half power stage and the ground bond wire in the other half power stage may be positioned such that the mutual inductance between the power supply bond wire and the ground bond wire is maximized. The controller ground may be positioned substantially midway between the power supply bond wire in one half power stage and a respective ground bond wire in the other half power stage. The regulator controller may be placed between the regulator power stage and other analog circuitry to isolate the regulator power stage from the analog circuitry.

Apparatus and method for virtually shielding a synchronous switching regulator

A switching voltage regulator includes a switching transistor connected to conduct a current (i) between a supply voltage and a first node in response to a control signal which cycles the transistor on and off, and a 'pre-driver' circuit which provides the control signal. The control signal is pulled up and down with a current I. The pre-driver circuit adaptively varies Isuch that it is at a relatively low level when the rate of change of current i (di/dt) in the switching transistor is relatively high, and is at a relatively high level when di/dt is relatively low.

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Edison, NJ, United States of America

Xuesong Jiang