ABSTRACT
This chapter introduces peripherals and the idea of redundancy. Peripheral circuits play their role in randomly reaching the cell for reading or writing through row and column buffers and decoders, whereas sense amplifiers (SA) help not only in attaining the full voltage level available at the output but also in refreshing the Dynamic Random Access Memory (DRAM). The area consumed and the power dissipated by these peripheral circuits also becomes very important. DRAM operating modes are either asynchronous or synchronous. During the 1980s most of the DRAM constituent components were converted from n-channel metal-oxide-semiconductor (NMOS) to complementary MOS. With increased DRAM density, number of SAs also increased, occupying larger chip area as core of the SAs consisted of pairs of NMOS and p-type MOS transistors. Alpha particle-induced soft error is a serious problem in high-density DRAMs. In conventional redundancy applications in DRAMs without cell array division, defective word line addresses are programmed in the address comparators and compared with the input address.
