| 摘要 |
PURPOSE: A sense amp circuit of a semiconductor memory device is provided which can sense data of a cell accurately even when a discharge time of the cell is long, and can operate in a high frequency. CONSTITUTION: According to the sense amp circuit of a semiconductor memory device, a ROM cell array part(10) stores data, and a sense amp part(140) senses cell data twice being output from the ROM cell array part and then outputs it. And a timing control part(120) generates the first control signal(S1) controlling data output of the ROM cell array part and control signals(S2,S3,S4) to control an operation of the sense amp part. According to the sense amp part, the first buffer part(142) buffers the cell data by the second control signal from the timing control part and then outputs it to the first node(Nd12). The second buffer part(144) buffers the cell data by the third control signal from the timing control part after the first buffer part is operated and then outputs it to the first node. A capacitor(C11) is connected between the first node and the second node(Nd13). The first switching device discharges a potential of the second node to a ground potential while the first buffer part is operated by the fourth control signal from the timing control part. The first inverter(INV11) receives a signal of the second node and then inverts it and outputs it to the third node. And the second inverter(INV12) inverts an output signal of the first inverter and then outputs it to a bus line.
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