Standard Microsystems Corporation

Parameswaran K Gopalier

Khosrow Haj Sadeghi

Kelly P McClellan

A phase-locked-loop (PLL) has a current controlled oscillator (ICO) whose gain varies with its input current. The PLL also contains a charge pump that controls the input current of the ICO and therefore the output frequency of the ICO. The charge pump has a gain that is controlled by the ICO input current in a manner which linearizes the combination of charge pump and ICO. This results in a substantially constant loop gain for a PLL.

Phase-locked-loop with linear combination of charge pump and current

A G.sub.m -C filter is formed using transconductor elements having first and second degeneration FETs to which first and second control signals are applied. A phase-locked-loop is used to generate the control signals. The control range of the transconductor elements is increased so that the frequency response of the filter can be maintained over increased ranges of various parameters (e.g., supply voltage variations, temperature variations, etc.)

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Rancho Santa Margarita, CA, United States of America

Parameswaran K Gopalier