Texas Instruments Corporation

Tadashi Tachibana

Shunichi Sukegawa

Masashi Hashimoto

Hugh Pryor McAdams

Hiroyuki Yoshida

Takeshi Sakai

Yukihide Suzuki

Katsuo Komatsuzaki

Shinji Bessho

Makoto Saeki

Chitranjan N Reddy

Ngai H Hong

Ken Saitoh

A semiconductor memory device has an address buffer (200, 230). A pre-decoder circuit (202, 232) receives the output of the address buffer (200, 230), and a memory array (212) receives the output of the pre-decoder circuit. A main amplifier (216, 248) in turn receives the output of the memory array (212, 244). An address transition detector (ATD) pulse generator circuit (204, 234) also receives the output of the address buffer (200, 230), and a pulse delay circuit (208, 240) receives the output of the address transition detector pulse generator circuit (204, 234). The pulse delay circuit (208, 240) also provides a main amplifier signal to the main amplifier (216, 248). The memory device further includes a voltage generator (206, 236) that generates a back gate voltage which is provided as a low voltage supply (V.sub.BB) for the address transition detector (ATD) pulse generator circuit (204, 234) and the pulse delay circuit (208, 240). The address transition detector (ATD) pulse generator (204, 234) and the pulse delay circuit (208, 240) have a delay that is controlled by the back gate voltage (V.sub.BB) and has a reduced dependency on a high voltage supply (V.sub.DD) of the memory device.

Semiconductor memory device having a back gate voltage controlled delay

A circuit is designed with a first lower conductor (500) having two ends. One end of the first lower conductor is coupled to a first signal source (386). A first upper conductor (544) has two ends and is spaced apart from the first lower conductor by a distance less than an allowable spacing between adjacent lower conductors. One end of the first upper conductor is coupled to a second signal source (384). A second upper conductor (508) has two ends. One end of the second upper conductor is coupled to another end of the first lower conductor for receiving a signal from the first signal source. A second lower conductor (552) has two ends and is spaced apart from the second upper conductor by a distance less than the allowable spacing between adjacent lower conductors. One end of the second lower conductor is coupled to another end of the first upper conductor for receiving a signal from the second signal source. Since the upper and lower conductors are spaced apart by a distance less than an allowable spacing between adjacent lower conductors, layout area is conserved. Total resistance of conductors connected to each signal source is the same, so signal delay is the same.

Matched delay word line strap

A semiconductor memory device in which erroneous operation with respect to undesired level changes of the input address signal is prevented, and appropriate operation of the main amplifier is ensured. The semiconductor memory device has a main amplifier activating pulse generator 112' which includes response sensitivity reduction circuit 10, response sensitivity selector 12, and main amplifier activating pulse generator 14. The response sensitivity reduction circuit 10 can reduce the response sensitivity or input sensitivity of the circuit 112' with respect to an input address transition detection pulse ATD. The response sensitivity selector 12 selects either a first input terminal A1 or a second input terminal A2, depending on the output state of the main amplifier activating pulse generator 14. Consequently, when there is no output of a main amplifier activating pulse MA from the main amplifier activating pulse generator 14, the response sensitivity selector 12 switches to first input terminal A1 to select response sensitivity reduction circuit 10; when a main amplifier activating pulse MA is output, the selector 12 switches to second input terminal A2 to select bypass circuit 11.

Semiconductor memory device

A semiconductor memory device which has a memory portion and a counter to count rows and/or columns of the memory portion, the counter being so constructed to return to a reset mode at the beginning of an address counting sequence when coming up to an arbitrary address such that an address or addresses corresponding to a region of the memory containing one or more defective memory cells and occurring after the arbitrary address are inaccessible. The counter thereby comprises a defective bit relief circuit built into the memory device.

Semiconductor memory with built-in defective bit relief circuit

A memory device including a voltage stepdown circuit is proposed in which a reduced reference voltage is produced from a supplied reference voltage and is passed to the selected one of the row lines of the memory array after all the row lines are discharged to ground potential, while the supplied reference voltage is fed directly, viz., without reduction, to all the control circuits of the device. The voltage stepdown circuit provided in the memory device is thus relieved from the burden to supply current to the control circuits and has only to feed the selected one of the row lines so that the field-effect transistors forming the voltage stepdown circuit can be fabricated to have channel regions with significantly reduced widths.

Semiconductor ROM with reduced supply voltage requirement

A semiconductor dynamic read/write memory of the multiplexed-address type employs an on-chip refresh counter which is activated by CAS-before-RAS sequence. This counter is made up of stages almost identical to the row address buffers so the same clocks can be used. Either the address input buffers or the refresh counter stages are gated into second-stage row address buffers, and carry feedback from these second stage buffers to the counter stages is used to increment the counter. The access time of the memory for normal read or write is not degraded by the refresh circuitry.

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Tsuchiura, Japan

Tadashi Tachibana