Sun Microsystems, Inc.

James F Testa

Edward H Frank

Andreas V Bechtolsheim

Shawn F Storm

Godfrey P D'Souza

Jens U Horstmann

Jonathan J Stinehelfer

James W Rose

James B Burr

Clifford B Willis

Robert S Antonuccio

James M Carney

Robert J Lajara

David R Emberson

Steven J Furuta

Daniel D Gonsalves

Vince P Hileman

William Leslie Dailey

Joseph M Spano

Mathew J Palazola

Bradley W Hoffert

Douglas A Laird

Hassan Siahpolo

Andreas Behtolsheim

Trevor Creary

A single in-line memory module (SIMM) for memory expansion in a computer system. The SIMM includes a plurality of memory chips surface-mounted on a printed circuit board. The printed circuit board includes a dual read-out connector edge adapted for insertion within a socket of the computer system. One or more driver chips may further be mounted on the printed circuit board and connected to distribute control signals to the memory chips. A full-width data path may further be connected between the dual read-out connector edge and the plurality of memory chips.

Single in-line memory module

A dynamic clocked inverter latch with reduced charge leakage includes a first node biasing circuit with a P-MOSFET and an N-MOSFET totem-pole-coupled between VDD and an output node, and a second node biasing circuit with another N-MOSFET and another P-MOSFET totem-pole-coupled between the output node and VSS. The first P-MOSFET receives an input data signal and the first N-MOSFET receives a clock signal and in accordance therewith together cause the output node to charge to a charged state having a charge voltage associated therewith. The second N-MOSFET also receives the input data signal while the second P-MOSFET receives the inverse of the clock signal and in accordance therewith together cause the output node to discharge to a discharged state having a discharge voltage associated therewith. During inactive states of the clock signal, the first N-MOSFET becomes reverse-biased by the output node discharge voltage, while during inactive states of the inverse clock signal, the second P-MOSFET becomes reverse-biased by the output node charge voltage, thereby virtually eliminating charge leakage to and from the output node, respectively.

Dynamic clocked inverter latch with reduced charge leakage

A storage cell includes a first bit line, a storage circuit, and a pass transistor. The storage circuit has a first storage node for holding a logic state indicative of a logic value. The pass transistor is coupled to the first bit line and the first storage node for establishing a conduction path therebetween. The pass transistor receives a bias voltage to switch the pass transistor into a substantially nonconducting state when the storage cell is not being accessed. The reverse bias on the first transistor substantially reduces the leakage current through the pass transistor.

Storage cell using low powered/low threshold CMOS pass transistors

A data latch with reduced data signal leakage includes a latch circuit and a clock buffer circuit which provides a differential clock signal to the input transmission gate of the latch circuit. The clock buffer circuit is biased between upper and lower supply voltage potentials which are higher and lower, respectively, than those between which the latch circuit is biased. This causes the differential clock signal to be overdriven with respect to the incoming data signal which is latched by the latch circuit. As a result, the input transmission gate of the latch circuit is reverse-biased during the inactive state of the differential clock signal, thereby isolating the storage node within the latch circuit and preventing signal leakage therefrom.

Low power data latch with overdriven clock signals

The system of the present invention provides for the verification and testing of electrical circuits and the generation of the information necessary to interface with computer aided testing equipment to physically test the fabricated circuits. The verification of the circuit is divided into two portions, functional verification and timing verification. Information generated during the verification process using the separate functional and timing verification information are then combined into a core structure from which test vectors are generated in a format compatible with a circuit testing apparatus which physically tests the fabricated circuit. In this format, unit delays previously employed to perform the timing tests are adjusted according to the timing specifications of the components to comply with the setup and hold times specified. Using this process, the test vectors required by the physical test apparatus to physically test a fabricated circuit are generated.

Method and apparatus for the verification and testing of electrical

A full width single in-line memory module (SIMM) for dynamic random access memory (DRAM) memory expansions. A printed circuit board having a multiplicity of DRAM memory elements mounted thereto is arranged in a data path having a width of 144 bits. The SIMM further includes on-board drivers to buffer and drive signals in close proximity to the memory elements. In addition, electrically conductive traces are routed on the circuit board to reduce loading and trace capacitance to minimize signal skew to the distributed memory elements. The SIMM further includes a high pin density dual read-out connector structure receiving electrical traces from both sides of the circuit board for enhanced functionality. The SIMM is installed in complementary sockets one SIMM at a time to provide memory expansion in full width increments. Finally, symmetrical power and ground routings to the connector structure ensure that the SIMM cannot be inserted incorrectly, wherein physically reversing the SIMM in the connector slot will not reverse power the SIMM.

A method and apparatus is disclosed for protecting a solder pad for a chip on tape packaged integrated circuit mounted on a surface of a printed circuit board that is exposed to a wave soldering operation. A pad cover may be used to protect the solder pad. The pad cover is mounted over the solder pad in a manner that protects the solder pad from being exposed to solder during the wave solder operation. After the wave solder is completed, the cover is removed and the leads of the chip on tape packaged integrated circuit are connected to associated solder pad traces on the printed circuit board. This type of arrangement is particularly useful in arrangements which require a heat sink to cool the chip on tape packaged integrated circuit.

Protecting cot packaged ICs during wave solder operations

A full width single in-line memory module (SIMM) for dynamic random access memory (DRAM) memory expansions is disclosed. A printed circuit board having a multiplicity of DRAM memory elements mounted thereto is arranged in a data path having a width of 144 bits. The SIMM of the present invention further includes on-board drivers to buffer and drive signals in close proximity to the memory elements. In addition, electrically conductive traces are routed on the circuit board in such a manner to reduce loading and trace capacitance to minimize signal skew to the distributed memory elements. The SIMM further includes a high pin density dual readout connector structure receiving electrical traces from both sides of the circuit board for enhanced functionality. The SIMM is installed in complementary sockets one SIMM, at a time to provide memory expansion in full width increments. Finally, symmetrical power and ground routings to the connector structure insure that the SIMM cannot be inserted incorrectly, wherein physically reversing the SIMM in the connector slot will not reverse power the SIMM.

An improved attachment mechanism for attaching the motherboard in a computer system to its chassis is disclosed. The attachment mechanism includes a rail that engages at least two opposing edges of the motherboard and a hook mechanism that engages a catch formed in the chassis. The hook mechanism is secured to a central portion of the motherboard. The rail and hook mechanism cooperate to securely couple the motherboard to the chassis without requiting the use of extensive usable space on the motherboard. The described arrangement permits the motherboard to be quickly and easily installed and released.

Printed circuit board attachment mechanism

A full width single in-line memory module (SIMM) for dynamic random access memory (DRAM) memory expansions is disclosed. A printed circuit board having a multiplicity of DRAM memory elements mounted thereto is arranged in a data path having a width of 144 bits. The SIMM of the present invention further includes on-board drivers to buffer and drive signals in close proximity to the memory elements. In addition, electrically conductive traces are routed on the circuit board in such a manner to reduce loading and trace capacitance to minimize signal skew to the distributed memory elements. The SIMM further includes a high pin density dual readout connector structure receiving electrical traces from both sides of the circuit board for enhanced functionality. The SIMM is installed in complementary sockets one SIMM at a time to provide memory expansion in full width increments. Finally, symmetrical power and ground routings to the connector structure insure that the SIMM cannot be inserted incorrectly, wherein physically reversing the SIMM in the connector slot will not reverse power the SIMM.

A full width single in-line memory module (SIMM) for dynamic random access memory (DRAM) memory expansions is disclosed. A printed circuit board having a multiplicity of DRAM memory elements mounted thereto is arranged in a data path having a width of 144 bits. The SIMM of the present invention further includes on-board drivers to buffer and drive signals in close proximity to the memory elements. In addition, electrically conductive traces are routed on the circuit board in such a manner to reduce loading and trace capacitance to minimize signal skew to the distributed memory elements. The SIMM further includes a high pin density dual read-out connector structure receiving electrical traces from both sides of the circuit board for enhanced functionality. The SIMM is installed in complementary sockets one SIMM at a time to provide memory expansion in full width increments. Finally, symmetrical power and ground routings to the connector structure insure that the SIMM cannot be inserted incorrectly, wherein physically reversing the SIMM in the connector slot will not reverse power the SIMM.

A bus architecture and protocol for integrated data and video memory. A high speed dedicated memory bus is coupled to a memory controller. The memory controller is in turn coupled to a multiple processor bus interconnecting one or more processors. Single in-line memory modules (SIMMs) incorporating dynamic random access memory (DRAM), video RAM (VRAM), and static nonvolatile RAM (SRAM) are coupled to the memory bus. Bus control signals forming a bus protocol, and address and data lines from the memory controller are shared by all memory modules operating on the memory bus. Certain control signals invoke specific operations on memory modules or are ignored, depending on the type of memory module receiving the control signal. The memory modules incorporate the consistent protocol by virtue of a consistent control signal pin out. The SIMMs further incorporate buffering and conversion functions, thereby relieving the memory controller of service overhead associated with these functions. Integrating all forms of memory into a single data and video memory architecture permits a highly functional dedicated memory bus to be connected to the computer system.

Bus architecture for integrated data and video memory

A multiple bus architecture for flexible communication between processors, memory subsystems, and specialized subsystems over multiple high performance communication pathways. The multiple bus architecture enables flexible communication between processors and devices coupled to a multiprocessor bus, a system interconnect bus, an external bus, an input/output bus, and a memory subsystem. Processor modules coupled to multiprocessor bus slots access the memory subsystem over the multiprocessor bus. System interconnect modules coupled to system interconnect bus slots access the memory subsystem via the system interconnect bus, and the multiprocessor bus. Processor modules coupled to multiprocessor bus slots access devices on the external bus via the system interconnect bus.

Multiple bus architecture for flexible communication among processor

An improved high speed, high density Dynamic Random Access Memory (DRAM) electrical signal interconnect structure which has particular application to computer systems which employ Single In-line Memory Modules (SIMMs). The structure contains an on-board buffer for driving time critical signals from a single source and further includes innovative signal trace routing having approximately equivalent minimum distance signal line lengths and vias to memory modules on the front and back surfaces of the circuit board resulting in a high speed, high density SIMM with clean rising/falling signal edges.

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Mountain View, CA, United States of America

James F Testa