Broadcom Corporation

Lsi Corporation

Avago Technologies General IP (singapore) Pte. Ltd.

Zeevo, Inc.

Edwin X Li

Tom McKay

Vas Postoyalko

Ross Wilson

Stephen Allott

Jason S Goldberg

Louis Pandula

Carol Barrett Huang

Individual magneto-resistive read elements are connected to the pre-amplifier through a multi-conductor transmission line; one side of each magneto-resistive read element is taken to a single common lead which is also received in the read pre-amplifier. Amplification and bias control are performed by the read pre-amplifier. A low-noise input stage amplifier configuration accommodates a shared common lead in a multi-head environment. Means for independently biasing the magneto-resistive read elements are also provided. Feedback loops are employed to regulate the operating points of the input stages, and to set the potential of the common head terminal. Two-dimensional magnetic recording system testability is enhanced by ability to multiplex any head to a single system output.

Pre-amplifier input stage for multi-element magneto-resistive heads

The disclosure is directed to a low noise amplifier (LNA) configuration that compensates for DC offsets of incoming signals from a magnetoresistive head. According to various embodiments, the LNA includes a shunt-feedback differential pair of amplifiers adaptively biased according to a detected input DC voltage offset of the incoming signals from the magnetoresistive head. The LNA is thus enabled to amplify the AC signal component substantially unaffected by the DC offset. The DC component in the LNA output signal is then removable via offset compensating circuitry located between the LNA and subsequent stages without significant signal-to-noise ratio (SNR) penalty.

Offset-tolerant low noise amplifier

A balun that includes a first conductor, a second conductor, and a third conductor. The first conductor has a first length. The first conductor also has a first end connected to a first balanced power amplifier output port. The second conductor has substantially the same first length. The second conductor also includes a first end connected to a second balanced power amplifier output port and a second end connected to a second end of the first conductor. The third conductor has substantially the same first length. The third conductor has a first end connected to an antenna port and a second end connected to a ground potential.

Communication transceiver having a three-line balun with power amplifier bias

A transceiver is described that includes a power amplifier (PA), a low noise amplifier (LNA), and an impedance matching circuit having a first and second differential output node. The first and second differential output nodes are coupled to outputs of the PA and to inputs of the LNA. The impedance matching circuit provides a load impedance to the outputs of the PA. The transceiver further includes a first impedance device having an output impedance coupled between the first and second differential output nodes. In this way, the combination of the output impedance and the load impedance matches with an impedance at the inputs of the LNA.

Apparatus for controlling impedance

System and apparatus for a three-line balun with power amplifier bias

A method and apparatus for determining a delay vector from inputs of in-phase and quadrature phase low pass filters to an output of the demodulator of a dual mixer radio receiver and from such delay measurement computing and providing DC offset correction to said receiver.

DC offset correction for use in a radio architecture

A balun that includes a first conductor, a second conductor and a third conductor. The first conductor has a first length. The first conductor also has a first end connected to a first balanced power amplifier output port. The second conductor has substantially the same first length. The second conductor also includes a first end connected to a second balanced power amplifier output port and a second end connected a second end of the first conductor. The third conductor has substantially the same first length. The third conductor has a first end connected to an antenna port and a second end connected to a ground potential.

System method and apparatus for a three-line balun with power amplifier bias

A balun that includes a first conductor, a second conductor and a third conductor. The first conductor has a length of about one quarter wavelength of a selected center frequency. The first conductor also has a first end connected to a first balanced power amplifier output port. The second conductor has a length of about one quarter wavelength of the selected center frequency. The second conductor also includes a first end connected to a second balanced power amplifier output port and a second end connected a second end of the first conductor. The third conductor has a length of about one quarter wavelength of the selected center frequency. The third conductor has a first end connected to an antenna port and a second end connected to a ground potential.

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San Jose, CA, United States of America

Edwin X Li