Integrated circuit having a variable RF resistor
AssigneeDiablo Research Corporation
InventorMichael E. McGillan
Life of this patent
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Abstract
A bipolar radio frequency (RF) integrated circuit having a functional equivalent of a PIN diode. The RF integrated circuit includes a low frequency lateral PNP transistor having an emitter having a P+ region, a collector having a P+ region, a base having an N+ region and an N region having a current dependent stored charge having a relatively low level when no current is flowing between the emitter and a junction connecting the base and collector. An RF resistance between the emitter and the junction is controlled by a bias applied from the emitter to the junction. By varying the bias, the low frequency lateral PNP transistor from the emitter to the junction is used as a variable RF resistor or as an RF signal carrying component in a variable attenuator or RF switch.
Claims12
A method for switching a radio frequency (RF) signal in an RF integrated circuit having low frequency lateral PNP transistors, each of said lateral transistors including a collector having a P+ region, an emitter having a P+ region, a base having an N+ region and an N region having a current dependent stored charge, comprising steps of:
- connecting a collector of a first one of said lateral transistors to a base of said first one of said lateral transistors at a first junction;
- coupling one of (i) said first junction and (ii) an emitter of said first one of said lateral transistors to a first circuit port;
- coupling the other of (i) said first junction and (ii) said emitter of said first one of said lateral transistors to an output junction;
- alternatively providing a first bias state for driving a forward current into said emitter of said first one of said lateral transistors and out of said first junction for enabling an RF signal to pass between said output junction and said first circuit port;
- or
- providing a second bias state for applying a negative voltage from said emitter of said first one of said lateral transistors to said first junction for inhibiting an RF signal from passing between said output junction and said first circuit port.
A radio frequency (RF) switch in an RF integrated circuit, comprising:
- a lateral transistor including an emitter having a P+ region, a collector having a P+ region, a base having an N+ region and an N region having a current dependent stored charge;
- said collector and said base connected at a first junction;
- one of (i) said emitter and (ii) said first junction coupled to a first circuit port and the other of (i) said emitter and (ii) said first junction connected to an output junction;
- and
- a bias circuit having a first bias state and a second bias state, said first bias state for driving a forward current into said emitter and out of said first junction for enabling an RF signal to pass between said output junction and said first circuit port, and said second bias state for applying a negative voltage from said emitter to said first junction for inhibiting an RF signal from passing between said output junction and said first circuit port.
A method for attenuating a radio frequency (RF) signal in an RF integrated circuit including low frequency lateral PNP transistors, each of said lateral transistors having a collector having a P+ region, an emitter having a P+ region, a base having an N+ region and an N region having a current dependent stored charge, comprising steps of:
- connecting a collector of a first one of said lateral transistors to a base of said first one of said lateral transistors at a first junction;
- coupling an emitter of said first one of said lateral transistors and said first junction in shunt across said RF signal;
- applying a variable first forward bias current into said emitter of said first one of said lateral transistors and out of said first junction;
- controlling a first stored charge according to said first current;
- controlling a first RF resistance between said emitter of said first one of said lateral transistors and said first junction according to said first stored charge;
- and
- variably attenuating said RF signal according to said first RF resistance.
A radio frequency (RF) variable attenuator in an RF integrated circuit, comprising:
- a lateral transistor including an emitter having a P+ region, a collector having a P+ region, a base having an N+ region and an N region having a current dependent stored charge, said collector and said base connected at a first junction;
- said emitter and said first junction coupled for shunting an RF signal;
- and
- a variable bias circuit for applying a variable forward current into said emitter and out of said first junction, said current controlling said stored charge for controlling an RF resistance between said emitter and said first junction for variably attenuating said RF signal according to said current.
A method for providing a variable radio frequency (RF) resistance in an RF integrated circuit having lateral PNP transistors, each said lateral transistor having an emitter having a P+ region, a collector having a P+ region, a base having an N+ region and an N region having a current dependent stored charge, comprising steps of:
- connecting a collector of a first one of said lateral transistors and a base of said first one of said lateral transistors at a junction;
- and
- connecting a variable bias circuit for driving a variable forward bias current into an emitter of said first one of said lateral transistors and out of said junction for alternatively increasing and decreasing said stored charge for responsively decreasing and increasing, respectively, said RF resistance between said emitter and said junction.
A radio frequency (RF) integrated circuit having an RF resistor having a variable resistance, comprising:
- a lateral PNP transistor including an emitter having a P+ region, a collector having a P+ region, a base having an N+ region and an N region having a current dependent stored charge, said collector and said base connected at a junction;
- and
- a variable bias circuit for driving a variable forward bias current into said emitter and out of said junction, for alternatively increasing and decreasing said stored charge for responsively decreasing and increasing, respectively, said RF resistance between said emitter and said junction.
Dependencies are inferred from the claim text.