Abstract: A ring oscillator (and test circuit incorporating the ring oscillator and test method therefor) includes an odd number of elements interconnected in a serially-connected infinite loop, each oscillator element having an associated programmable delay feature. The circuit can be used to measure effects of Negative Bias Temperature Instability (NBTI) in p-channel MOSFETs (PFETs).

Abstract: Provides within a semiconductor chip a plurality of internal DRAM arrays connected to each section data bus. A cross-point switch simultaneously connects the plural section data buses to a corresponding plurality of port registers that transfer data between a plurality of ports (I/O pins) on the chip and the section data buses in parallel in either data direction to effectively support a high multi-port data rate to/from the memory chip. For any section, the data may be transferred entirely in parallel between the associated port and a corresponding port register, or the data may be multiplexed between each port and its port register in plural sets of parallel bits. Each of the DRAM banks in the chip is addressed and accessed in parallel with the other DRAM banks through a bank address control in the chip which receives all address requests from four processors in a computer system.

Abstract: A programmable self-time refresh circuit for a semiconductor memory and methods for programming the self-refresh rate for non-invasively and deterministically testing the self-timed refresh circuit for establishing/verifying a refresh rate and a wait state interval for the self-refresh operation. The programmable refresh circuit includes a self-timed oscillator that outputs a clocking signal, and a programmable pattern generator that outputs a first signal pattern and a second signal pattern. The first signal pattern is fed to a counter circuit which also receives the clocking signal. The counter circuit outputs a signal pulse whenever the count driven by the clocking signal reaches a digital pattern representation corresponding to the first signal pattern generated by the programmable pattern generator. Refresh control logic is connected to receive the pulse signal and respond thereto by refreshing a portion of the memory array of the semiconductor memory device.