Afshin D Momtaz

6389092, May 14, 2002

Jul 12, 2000

09/615033

Afshin Momtaz - Irvine CA

NewPort Communications, Inc. - Irvine CA

H03L 7093

375376, 327157, 331 14, 331 17

A phase locked loop circuit having a loop filter including a variable resistance for normal loop operation and for fast acquisition has improved stability by defining a loop pole separate from the loop filter. The loop pole remains constant during transition periods of the filter resistance. The loop pole remains constant while loop bandwidth is varied for either phase acquisition or normal operation, and the ratio of bandwidth to pole varies only linearly which makes the phase locked loop more stable during the bandwidth adjustment.

6526113, Feb 25, 2003

Mar 31, 2000

09/540243

German Gutierrez - Carlsbad CA
Afshin Momtaz - Irvine CA

Broadcom Corporation - Irvine CA

H03D 324

375376, 327156, 327157, 331 25, 331 32

Various circuit techniques employ a transconductance (gm) cell in control loops to implement circuits such as phase locked loops and delay locked loops that are capable of operating at ultra high frequencies with improved precision and noise performance. The gm cell is designed to operate on an analog input signal with a very small swing and more gradual transition edges. These characteristics allow implementation of high frequency circuits and systems including, for example, transceivers for fiber optic channels, disk driver electronics and the like.

6549599, Apr 15, 2003

Mar 11, 2002

10/095556

Afshin Momtaz - Irvine CA

Broadcom Corporation - Irvine CA

H03L 7093

375376, 327157, 331 14, 331 17

A phase locked loop circuit having a loop filter including a variable resistance for normal loop operation and for fast acquisition has improved stability by defining a loop pole separate from the loop filter. The loop pole remains constant during transition periods of the filter resistance. The loop pole remains constant while loop bandwidth is varied for either phase acquisition or normal operation, and the ratio of bandwidth to pole varies only linearly which makes the phase locked loop more stable during the bandwidth adjustment.

6621362, Sep 16, 2003

May 18, 2001

09/860284

Afshin Momtaz - Irvine CA
Armond Hairapetian - Glendale CA

Broadcom Corporation - Irvine CA

H03L 708

331117R, 331117 FE, 331167, 331177 V

Method and circuitry for implementing VCOs with improved frequency band switching use differentially-coupled varactors to implement the different frequency bands. According to a specific embodiment, one side of a varactor couples to the tank circuit and the other side is coupled either to ground or to the positive power supply VDD without introducing any series parasitic resistance.

6696854, Feb 24, 2004

Sep 17, 2001

09/956374

Afshin Momtaz - Irvine CA
Xin Wang - Irvine CA
Jun Cao - Irvine CA
Armond Hairapetian - Glendale CA
David Chung - Newport Beach CA

Broadcom Corporation - Irvine CA

G11C 700

326 37, 326 40, 365221

Methods and circuitry for implementing high speed first-in first-out (FIFO) structures. In one embodiment, a FIFO is disclosed that allows the frequency of one clock, e. g. , the write clock, to be different than (e. g. , half) that of the other (read) clock. In another embodiment a FIFO is presented that can be set and/or reset asynchronously. Other embodiments are disclosed wherein the read and write pointers are effectively monitored to ensure proper timing relationship, to detect loss of clock as well as to detect other abnormal FIFO conditions.

6721380, Apr 13, 2004

Jul 31, 2001

09/919636

Armond Hairapetian - Glendale CA
Jun Cao - Irvine CA
Afshin Momtaz - Irvine CA

Broadcom Corporation - Irvine CA

H03L 708

375376, 375374, 327148, 327157, 331 25

The present invention relates in general to integrated circuits, and in particular to method and circuitry for implementing an improved phase-locked loop (PLL) in complementary metal-oxide-semiconductor (CMOS) technology using current-controlled CMOS (C MOS) logic. In an exemplary embodiment, a phase-locked loop includes a phase-frequency detector, a Gm cell block, a low pass filter and a voltage controlled oscillator. These various elements of the phase-locked loop are connected to one another in a fully differential manner, i. e. , each element has an input and/or an output each having at least a differential signal. In one embodiment, each of these various elements of the phase-locked loop is implemented using C MOS logic.

6725408, Apr 20, 2004

Aug 7, 2000

09/632666

Jun Cao - Irvine CA
Afshin Momtaz - Irvine CA

Broadcom Corporation - Irvine CA

G06F 1100

714738, 714742

A method and device for testing multi-channel transceivers in an integrated circuit is provided. More specifically, the present invention relates to a method and device for implementing a built-in self-test for multi-channel transceivers. An exemplaxy embodiment of the present invention includes a test pattern generator, a multiplexer, a demultiplexer, and a test result evaluator. The test pattern generator generates a test pattern which is fed into each of the input channels of the multiplexer. The multiplexer multiplexes the data from all its input channels and then relays the data to the demultiplexer. The test result evaluator then individually checks the data at each of the output channels of the demultiplexer to determine whether the data received at each output channel is the same as the test pattern. In order to facilitate the checking process, signature analysis is utilized.

6748041, Jun 8, 2004

Dec 13, 2002

10/318586

Germain Gutierrez - Carlsbad CA
Afshin Momtaz - Irvine CA

Broadcom Corporation - Irvine CA

H03D 324

375376, 327156, 327157, 331 25, 331 32

Various circuit techniques employ a transconductance (gm) cell in control loops to implement circuits such as phase locked loops and delay locked loops that are capable of operating at ultra high frequencies with improved precision and noise performance. The gm cell is designed to operate on an analog input signal with a very small swing and more gradual transition edges. These characteristics allow implementation of high frequency circuits and systems including, for example, transceivers for fiber optic channels, disk driver electronics and the like.