Elpida Memory, Inc.

Longitude Semiconductor S.a.r.l.

Daiki Nakashima

Koji Kuroki

Shuichi Kubouchi

Ryuuji Takishita

To provide an electrical fuse that is connected to a detection node via a selective transistor, a precharge transistor that precharges the detection node in a state where the selective transistor is off; a bias transistor that passes a bias current to the detection node in a state where the selective transistor is on and the precharge transistor is off, and a detection circuit that detects a potential of the detection node in a state where the bias current is flowing into the detection node, wherein the bias transistor reduces an amount of the bias current in a stepwise manner or a continuous manner.

Semiconductor device having electrical fuse and control method thereof

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.

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Tokyo, Japan

Daiki Nakashima