| 摘要 |
<p>PURPOSE:To perform high speed readout by providing a bipolar transistor for a Y selector whose bit line is connected to an emitter directly or through a transfer gate for a Y selector and outputs an input signal to a base and a bit line signal to a collector. CONSTITUTION:When the base potential of the Y selector transistor 21 rises from 0 to 2V, the bit line 3 is changed from 0 to 1.3V accompanied with the rise of the base potential. The charging current ie at this time becomes the sum of a collector current ic and a base current ib. As to the ic, such a large amount of base current ib is transiently supplied that the bit line is raised from an earth level and the collector current flows to the bit line through the current path with low conductance of an R1 and transistors 26 and 21, so that the bit line 3 can be rapidly charged. The potential Vsense of a sense line 25 is expressed with a parameter used in a current sense type amplification circuit 22. Output voltage obtained in the current sense type amplifier 22 is small and delay for amplifying the output voltage to the maximum one is made very small differently from the case of the amplification of mV level. Thus, the high speed readout of data is accomplished.</p> |
