| 摘要 |
PURPOSE:To prevent a load capacity of a readout signal line from increasing by separating a collector of a bipolar differential amplifier constituting a sense amplifier from the readout signal line. CONSTITUTION:Transfer gates 51, 511-51N, 52 and 521-52N consisting of a MOS transistor are connected respectively between the bipolar differential amplifier 30 and one pair of the readout signal lines 41 and 42. In this case, the load capacity of the readout signal lines 41 and 42 is made by summing up a wiring capacity, a collector/substrate capacity of one selected bipolar differential amplifier 30 and a source-drain coupling capacity of all the transfer gates 51 and 52, whereas the source-drain coupling capacity of one transfer gate is extremely less than the collector/substrate capacity of one bipolar differ ential amplifier. By this method, the load capacity of the readout signal lines 41 and 42 can remarkably be lessened.
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