Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Engineering Company, Limited

Tooru Ichimura

Youichi Tobita

Shigeru Mori

Masanori Hayashikoshi

Susumu Tanida

Hiroshi Akamatsu

Mikio Sakurai

Yukinobu Adachi

Hiromi Okimoto

Kazuhiro Sakemi

A semiconductor memory device includes: subarrays having memory cells each arranged at cross points of a plurality of bit lines and a plurality of word lines; a row decoder for selecting among the word lines; a column decoder for supplying a select signal to transfer gates for selecting among paired bit lines; and a clamping circuit for fixing the potential of a column select line at a constant potential before the column decoder is activated.

Semiconductor memory device with clamping circuit for preventing

An external power source voltage Vcc rises until it exceeds the threshold voltage Vth of an NMOS transistor diode-connected between the external power source (voltage Vcc) and an internal boosted power source (voltage Vpp), whereupon the NMOS transistor is turned on, supplying the internal boosted power source with a voltage (Vcc-Vth) until the power source voltage Vcc reaches its final value. And when the internal reset signal ZPOR expires, the internal boosted power source generating circuit is started to operate so that the internal boost source voltage Vpp is boosted to an intended level Vpp. As a result, when the power is turned on, early stabilization of the boosted power source voltage is realized in a semiconductor storage device.

Semiconductor storage device requiring short time for program voltage to

A semiconductor memory device includes a memory cell array (1) having a plurality of memory cells arranged in rows and columns, a plurality of column select lines (3) extending over the memory cell array and coupled to received column select signals generated by a column decoder (100), a plurality of power supply lines (4) provided in parallel with the column select lines to transfer a power supply voltage from a main power supply line (130), and a plurality of ground lines (5) provided in parallel with the column select lines to transfer a ground voltage from a main ground line. A plurality of fuse elements (6) are provided for each of the column select lines. When a short-circuit is found between a column select line and power supply line or a ground line, a fuse element corresponding to the short-circuited column select line is blown off and the short-circuited column select line is isolated from the column decoder. By repairing the short-circuited column select line with a redundant column select line (60), the memory device operates correctly without an adverse effect of the short-circuit.

Semiconductor device having an improved immunity to a short-circuit at a

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Hyogo, Japan

Tooru Ichimura