Low phase variation CMOS digital attenuator
AssigneeInternational Business Machines Corporation
InventorsPinping Sun, Hanyi Ding, Wayne H. Woods, Jr.
Life of this patent
Estimating the term…
Abstract
A low phase variation attenuator uses a combined attenuation path and a phase network to significantly reduce a phase error between a reference signal and an attenuated signal without degrading the insertion loss. A grounded parallel connection of a resistor and a capacitor is employed in series with an attenuation transistor, which is connected to a middle of a two resistor voltage divider. The two resistor voltage divider includes two resistors of equal resistance that are connected in a series connection. The two resistor voltage divider is connected in a parallel connection with a reference transistor, which functions as a main switch for the transmission or attenuation of a radio frequency (RF) signal.
Claims19
An attenuator circuit comprising:
- a parallel connection of a reference transistor and two resistors between a first node and a second node;
- and
- a series connection of an attenuation transistor and a complex impedance circuit, wherein a third node at one end of said series connection is a node between said two resistors, and a fourth node at another end of said series connection is electrically grounded, and wherein said complex impedance circuit is a parallel connection of a resistor and a capacitor.
A method of designing an attenuator circuit comprising:
- generating a circuit design for an attenuator circuit, said attenuator circuit including:
- a parallel connection of a reference transistor and two resistors between a first node and a second node, and
- a series connection of an attenuation transistor and a complex impedance circuit, wherein a third node at one end of said series connection is a node between said two resistors, and a fourth node at another end of said series connection is electrically grounded, wherein said complex impedance circuit is a parallel connection of a resistor and a capacitor;
- determining, employing a computing device, values for components of said attenuator circuit including values of components in said complex impedance circuit;
- and
- storing said circuit design and said values in a non-transitory machine-readable data storage medium.
Dependencies are inferred from the claim text.