Hyundai Electronics Industries Co. Ltd.

Lg Semicon Co., Ltd.

Boo Yong Park

Jin-Hong Ahn

Joong-ho Choi

A delay time compensation circuit for a clock buffer includes first and second toggle flip-flops multiplying an input clock signal and a delay clock signal which is delayed by an input buffer, respectively, a time interval extraction chain extracting a time interval between a rising edge of the input clock signal and a rising edge of the delay clock signal in accordance with clock signals multiplied in the first and second toggle flip-flops, and a variable delay chain delaying the input clock signal by a time interval extracted from the time interval extraction chain. The circuit employs a &frac12; multiplied clock signal and operates without regard to a duty cycle of an input clock signal, thereby compensating for all the delay time within the cycle of the input clock signal.

Delay time compensation circuit for clock buffer

Semiconductor memory device which can support a DDR SDRAM latency mode like 2.5 for easy application to a high data rate memory, including a memory cell array having a plurality of memory cell regions for storing external data and forwarding the data on two lines by a decoded column address, a data path unit for forwarding the data from the memory cell array received through the two lines outwardly synchronous to an edge of internal clock, a controlling unit for controlling the data path unit entirely, a FIFO unit for controlling a forwarding order of the two data received from the data path unit, a latency pipeline controlling unit for providing an Enable signal for setting a data output enable interval at each of the control unit and the data path unit, a clock generating unit for providing the internal clock to the FIFO unit, the data path unit and the latency pipeline controlling unit for obtaining a desired band width, and a burst counter for providing a read signal having information on a burst length to the FIFO unit and the latency pipeline control unit.

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Seoul, South Korea

Boo Yong Park