Samsung Electronics Co., Ltd.

Samsung Semiconductor & Telecommunication Co., Ltd.

Hyung-Kyu Lim

Dong-Wook Kim

Hee-Choul Park

Woo-Young Jang

Rustam J Mehta

Yong-Bo Park

Jae-Yeong Do

A data output buffer suitable for use in a semiconductor memory device includes a first input circuit coupled to a first data signal and a first control signal, e.g., an output enable signal, and a second input circuit coupled to a second data signal which is the inverse of the first data signal and the first control signal. The data output buffer also includes a pull-up circuit responsive to the output of the first input circuit for selectively raising the data output node to a high voltage level, e.g., Vcc, and a pull-down circuit responsive to the output of the second input circuit for selectively lowering the data output node to a low voltage level, e.g., Vss. The data output buffer further includes a preset circuit comprised of a first preset control circuit responsive to the output of the first input circuit and a second control signal, e.g., an inverse output enable signal, for selectively raising the data output node from the low voltage level to an intermediate voltage level, e.g., 1/2 Vcc, and a second preset control circuit responsive to the output of the second input circuit and the second control signal for selectively lowering the data output node from the high voltage level to the intermediate voltage level. The preset control circuit advantageously operates to maintain the data output node at the intermediate voltage level during active states of the output enable signal without generating any DC current, thereby eliminating the noise and reliability problems of presently available data output buffers.

Tristate data output buffer having reduced switching noise and

A normal decoder and a redundant decoder having address program devices are used for the replacement of bad cells. The number of address program devices is one more than the number of input address bits for selecting a normal row or column. The input signals of the additional program device are complementary to the input signals of one of the other program devices. The program of the program devices have two steps to repair the faulty cells. To increase the reliability of redundancy, a nonvolatile memory element used in the program devices is a bridge connected four cell FLOTOX type nonvolatile memory device.

Redundancy circuit for use in a semiconductor memory device

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Suwon, South Korea

Hyung-Kyu Lim