Elpida Memory, Inc.

Ps4 Luxco S.a.r.l.

Ryuuji Takishita

Koji Kuroki

Hideyuki Yoko

Hiroki Fujisawa

Daiki Nakashima

A semiconductor device includes a power-supply control portion and a latch portion. The power-supply control portion supplies power to an internal circuit in response to an input signal synchronized with rising of clock. The latch portion latches the input signal in synchronization with falling of the clock and supplies the latched input signal to the internal circuit.

Semiconductor device and timing control method for the same

A DLL circuit is designed to adjust the delay time and the duty applied to an input clock signal, thus producing a DLL clock signal. In a non-clocking state of the DLL clock signal in which pulses disappear temporarily, the DLL circuit stops updating the delay time and the duty of the DLL clock signal. That is, the DLL circuit is capable of preventing a phase difference between the input clock signal and the DLL clock signal from being erroneously detected in the non-clocking state of the DLL clock signal, thus preventing the delay time and the duty from being updated based on the erroneously detected phase difference. Thus, it is possible to reduce the number of cycles adapted to the delay-locked control and to thereby stabilize the operation of the DLL circuit.

DLL circuit adapted to semiconductor device

To suppress the number of clocks needed to adjust the impedance of an output buffer. A pull-up replica buffer is connected between a calibration terminal and power supply wiring, and is controlled in impedance by a DRZQP signal supplied from a counter. A pull-down replica buffer is connected between ground wiring and a connection node A, and is controlled in impedance by a DRZQN signal supplied from the counter. More specifically, the DRZQP signal and the DRZQN signal indicate count values. The impedances of the replica buffers are increased or decreased stepwise in proportion to the count values. The count values are updated according to a binary search method.

Semiconductor device and method of adjusting characteristic thereof

For example, four driver transistors are arranged in wells so as to adjoin both sides of each of two element isolation regions. Two pairs of cross-coupled sense transistors are arranged in the wells at positions farther from the element isolation regions than the driver transistors are. Such an arrangement provides more than a certain distance between the sense transistors and the respective corresponding element isolation regions. This reduces the effect of a phenomenon that threshold of a transistor varies according to a distance from an element isolation region. As a result, it is possible to exactly match the characteristics of each pair of cross-coupled transistors.

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Tokyo, Japan

Ryuuji Takishita