American Microsystems, Inc.

Waferscale Integration, Inc.

Larry Willis Petersen

Boaz Eitan

Mark Michael Nelson

Yaron Slezak

Rustom F Irani

Richard B Friel

Juergen John Roscher

A wordline driver for a semiconductor memory array having a circuit for selecting and deselecting the first end of an addressed wordline and a circuit for deselecting the second end of the addressed wordline. The first and second ends of the addressed wordline are deselected at substantially the same time. The first end of the wordline is selected and deselected responsive to a strobe waveform and the second end of the wordline is deselected responsive to an RL Strobe waveform. The RL Strobe waveform is derived from a delayed strobe waveform.

Strobed wordline driver for fast memories

An input buffer capable of operating at a first power supply voltage level or a second power supply voltage level with the operating voltage level selectable during manufacture. At least one shortable transistor is disposed between the power supply voltage input and a buffer circuit which is connected between an input and an output of the buffer circuit. When the first voltage is the intended operating voltage the at least one shortable transistor is shorted. The first operating voltage level meets the requirements of a CMOS device and the second operating voltage level meets the requirements of a TTL device. The shortable transistor can be either a p-channel or an n-channel transistor and the short can be done by a metal layer short, a polysilicon short, a depletion implant, or with vias during manufacture. Transistors in the buffer circuit are sized to provide an acceptable TTL device level trip point when the input buffer is operated at 5 volts and which also provides an acceptable CMOS device level trip point when the input buffer is operated at 3 volts. Transistors in the buffer circuit are provided to turn OFF the input buffer at the direction of an external circuit.

3V/5V input buffer

A read only memory (ROM) array is disclosed which includes a) a voltage supply providing an operating voltage level, b) a plurality of word-lines, c) a multiplicity of ROM transistors, and d) a word-line clamper. The ROM transistors are divided into turned on and turned off transistors. Each ROM transistor has a gate connected to one of the word-lines, a gate oxide beneath the gate, whose thickness is less than 250 .ANG., and a channel beneath the gate oxide. The turned off transistors additionally have a ROM implant in their channel whose dosage is no larger than the amount which generates a predetermined desired minimal band-to-band tunneling current The ROM implant and gate oxide thickness define a threshold voltage for the tamed off tranistors, the threshold voltage being less than the operating voltage level. The word-line damper provides a word-line voltage to each of the word-lines, the word-line voltage being clamped to a voltage level no higher than the threshold voltage of the turned off transistor.

Operating method for ROM array which minimizes band-to-band tunneling

A clock delay circuit for generating a delay for a sense amplifier release signal in an integrated circuit semiconductor memory device is disclosed. Rather than utilize traditional programmable capacitors that must be trimmed on a die by die basis, the novel clock delay circuit disclosed utilizes a small ROM, EPROM, EEPROM or FLASH array coupled to a bit line emulator to provide a clock delay matched to the larger main array. The size of the small memory array is on the order of 5 to 10 bit lines by 5 to 10 word lines. One cell within the small array is fixed to be continuously selected. The selected cell is coupled to the clock delay node along with the bit line emulator. The bit line emulator models the capacitance of the actual bit line used in the main array. However, the circuit is constructed so that a much larger signal is generated by the delay circuit such that sense amplifiers detect the correct signal. The CMOS based clock delay circuit uses the emulated array to generate a delta or margin that accurately tracks the delays within the main array with variations in temperature, supply voltage and process.

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Pocatello, ID, United States of America

Larry Willis Petersen