sentences:  The first generation (1 kbit) DRAM ICs, up until the 64 kbit generation (and some 256 kbit generation devices) had open bitline array architectures.In these architectures, the bitlines are divided into multiple segments, and the differential sense amplifiers are placed in between bitline segments.Because the sense amplifiers are placed between bitline segments, to route their outputs outside the array, an additional layer of interconnect placed above those used to construct the wordlines and bitlines is required.