US 11,121,702 B1 · Digital step attenuator

Abstract

Various embodiments of the invention relate to attenuators with reduced temperature variation. By coordinating first-order resistance temperature (FORT) coefficients of resistors, embodiments of attenuator or attenuator cells are capable of achieving desired attenuation with reduced or minimized temperature variation. Such achievements in reducing temperature variation may be obtained without relying on resistors with large negative FORT coefficients. Attenuator cells may be configured as T-type attenuator cells, π-type attenuator cells, bridged-T attenuator cells, or shunt attenuators with various FORT coefficient combinations for the resistors incorporated within the attenuator cells. Furthermore, various attenuator cells may be cascaded together into a digital step attenuator with the temperature variation of those cells compensating or offsetting each other for an overall minimum temperature variation.

Claims16

Dependent claims

A digital step attenuator comprising:

a first resistor and a second resistor coupled in series between an RF input port and an RF output port, the first resistor and the second resistor each has a first-order resistance temperature (FORT) coefficient with a positive value;
a shunt resistor coupled to a node interposed between the first resistor and the second resistor, the shunt resistor has a FORT coefficient with an absolute value at least one order of magnitude smaller than the positive value for the FORT coefficient of the first resistor and the positive value for the FORT coefficient of the second resistor;
a shunt switch coupled between the shunt resistor and a ground;
and
a bypass switch coupled between the RF input port and the RF output port, the attenuator is engaged for signal attenuation when the bypass switch is switched off and the shunt switch is switch on.

2 more elements

A digital step attenuator comprising:

a first attenuator cell comprising one or more resistors, the first attenuator cell has an attenuation increasing with temperature;
and
a second attenuator cell coupled in series to the first attenuation cell, the second attenuator cell comprising one or more resistors, the second attenuator cell has an attenuation decreasing with temperature to compensate the first attenuator cell such that an overall temperature variation of the attenuator is lowered.

Dependencies are inferred from the claim text.

Digital step attenuator

Life of this patent

Digital step attenuator

Life of this patent

Abstract

Claims16