Fairchild Semiconductor Corporation

Jianhong Ju

Pravas Pradhan

Yong Liu

Qiuxiao Qian

Howard Allen

A semiconductor die package. It includes a substrate having a first surface and a second surface, a first semiconductor die having its front surface facing the first surface of the substrate, a conductive adhesive disposed between the first semiconductor die and the first surface of the substrate, and a second semiconductor die located on the first semiconductor die. The front surface of second semiconductor die faces away from the first semiconductor die, and the back surface faces toward the first semiconductor die. A plurality of conductive structures electrically couple regions at the front surface of the second semiconductor die to conductive regions at the first surface of the substrate.

Stacked dual-die packages, methods of making, and systems incorporating said packages

A current mode transfer logic system suitable for driving transmission lines is disclosed. In one embodiment a twisted pair transmission line is terminated in its characteristic line impedance. A signal is formed of two unequal currents, preferably of different polarities as well as magnitudes, that are driven down the two lines. The unequal currents are selectively switched between the two lines creating a logic signal of a differential current drive of unequal current magnitudes. The unequal currents are received and shunted from the distal end of each line via diode connected MOS transistors. The MOS transistors are biased to present a low impedance, but an impedance higher than the terminating resistor. The currents are amplified and converted to useable CMOS voltage levels. In another embodiment the twisted pair is replaced by two parallel transmission lines which are terminated in one resistor, equal to the sum of the characteristic impedances of each line. The terminating resistor is connected between the distal signal carrying conductors of each transmission line. The shields or return paths for each line are tied together at the distal and at the proximate (drive) ends of the line.

Current transfer logic

A system and method are described for receiving differential currents in a current mode circuit. When conditions occur where the receiver inputs are floating, undriven, shorted together, or one or both shorted to ground, the output of the system remains stable. Diode connected MOS transistors receive the unequal currents, and current mirrors amplify the received currents. Those amplified mirrored currents are differentially amplified and converted into voltage signals suitable of typical computer and logic systems. The current mode differential nature of the invention provides high common mode current and voltage noise immunity. A threshold for the unequal currents helps provide high differential current and voltage noise immunity.

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Gorham, ME, United States of America

Jianhong Ju