Method and System to Reduce Electromagnetic Radiation for Semiconductor Devices
AssigneeTexas Instruments Incorporated
InventorsKevin P. Lavery, Jim D. Childers, Praven P. Patel
Life of this patent
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Abstract
Reducing electromagnetic radiation from semiconductor devices. At least some of the illustrative embodiments are methods comprising driving a Boolean state to a signal pad of a semiconductor device (the driving through a transistor with a first drain-to-source impedance during the driving), and maintaining the Boolean state applied to the signal pad through the transistor with a second drain-to-source impedance, higher than the first drain-to-source impedance.
Claims17
A method of a semiconductor device for reducing electromagnetic radiation of the semiconductor device, comprising:
- driving a Boolean state to a signal pad of a semiconductor device, the driving through a transistor with a first drain-to-source impedance during the driving;
- maintaining the Boolean state applied to the signal pad through the transistor with a second drain-to-source impedance, higher than the first drain-to-source impedance;
- and
- controlling drain-to-source impedance of the transistor and holding the Boolean state at a determine voltage range for reducing the electromagnetic radiation of the semiconductor device, wherein the reduction is from the internal rail of a pin.
A system comprising:
- a processor core;
- power rail;
- a ground rail;
- an external electrical connection;
- and
- an output buffer coupled the processor core, power rail, ground rail, and the external electrical connection, the output buffer comprising:
- a first transistor that defines a source, drain and gate;
- the drain coupled to the external electrical connection;
- and
- the source coupled to the ground rail;
- the system is configured to drive a logic low voltage state to the external electrical connection during a first period of time;
- the system is configured to induce a first drain-to-source impedance of the first transistor during a first portion of the first period of time;
- and
- the system is configured to induce a second drain-to-source impedance, higher than the first drain-to-source impedance, during the second portion of the first period of time to control the drain-to-source impedance of the transistor and to hold the Boolean state at a determine voltage range for reducing the electromagnetic radiation of the semiconductor device, wherein the reduction is from the internal rail of a pin.
A method of reducing electromagnetic interference comprising:
- driving a Boolean state to a signal pad of semiconductor device through a transistor by applying a first voltage to the gate of the transistor;
- maintaining the Boolean state applied to the signal pad through a transistor by applying a second voltage, different than the first voltage, to the gate of the transistor;
- and
- controlling drain-to-source impedance of the transistor and holding the Boolean state at a determine voltage range for reducing the electromagnetic radiation of the semiconductor device, wherein the reduction is from the internal rail of a pin.
A semiconductor device comprising:
- means for distributing a voltage common connection across the semiconductor device;
- means for coupling a signal to an external device;
- means for reducing electromagnetic radiation from the means for coupling caused, at least in part, by alternating current (AC) signals on the means for distributing;
- and
- controlling drain-to-source impedance of the transistor and holding the Boolean state at a determine voltage range for reducing the electromagnetic radiation of the semiconductor device, wherein the reduction is from the internal rail of a pin.
Dependencies are inferred from the claim text.