Attenuator De-Qing Loss Improvement and Phase Balance

Abstract

The de-Qing loss and phase imbalance caused by the inherent capacitance of a switched resistance, such as a MOSFET with a resistor, can be reduced by using a shunting switch across the resistor that is in series with the resistor's switch. The shunting switch shorts across the resistor when the resistor's switch is open and in reference mode, thereby significantly reducing the resistance in series with the inherent capacitance of the open resistor's switch.

Description

CROSS REFERENCE TO RELATED APPLICATIONS—CLAIM OF PRIORITY[0001]This application is a continuation of commonly owned and co-pending U.S. application Ser. No. 15 / 212,025, filed Jul. 15, 2016, entitled “Attenuator De-Qing Loss Improvement and Phase Balance”, the disclosure of which is incorporated herein by reference in its entirety.[0002]The present application may be related to U.S. patent application Ser. No. 15 / 212,046, filed on Jul. 15, 2016, entitled “Hybrid Coupler with Phase and Attenuation Control” (Attorney Docket No. PER-178-PAP), now U.S. Pat. No. 10,211,801 issued Feb. 19, 2019, and assigned to the assignee of the present disclosure, the contents of which are hereby incorporated by reference in their entirety.TECHNICAL FIELD[0003]Various embodiments described herein relate generally to systems, methods, and apparatus for improving de-Qing loss and phase balance for attenuator circuits.BACKGROUND[0004]Various devices can be switched between a reference mode and an attenuate...

AI Technical Summary

Benefits of technology

This configuration reduces de-Qing loss and phase imbalance, maintaining signal integrity and attenuation performance across a wider frequency range, as demonstrated by reduced insertion loss and improved phase balance in high-frequency applications.

Problems solved by technology

However, transistors in the off state are not perfect open circuits: they have small internal conductance and capacitance.

But most detrimental is the attenuating resistor that was intended to be left floating is now seen through the signal path and incurs loss to the system.

Additionally, the parasitic capacitance with the parallel resistance degrades phase imbalance increasingly as the signal frequency increases.

For lower frequencies, these losses might be within acceptable ranges, and so can be ignored for some designs; however, for high frequency circuits, the de-Qing and phase imbalance can be an issue.

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