DRAM – Dynamic Random Access Memory

DRAM chips are large, rectangular arrays of memory cells with support logic that is used for reading and writing data in the arrays, and refresh circuitry to maintain the integrity of stored data. Memory arrays are arranged in rows and columns of memory cells called wordlines and bitlines, respectively. Each memory cell has a unique location or address defined by the intersection of a row and a column. DRAM is manufactured using a similar process to how processors are: a silicon substrate is etched with the patterns that make the transistors and capacitors (and support structures) that comprise each bit. It costs much less than a processor because it is a series of simple, repeated structures, so there isn’t the complexity of making a single chip with several million individually-located transistors and DRAM is cheaper than SRAM and uses half as many transistors. Over the years, several different structures have been used to create the memory cells on a chip, and in today’s technologies the support circuitry generally includes: sense amplifiers to amplify the signal or charge detected on a memory cell address logic to select rows and columns Row Address Select (RAS) and Column Address Select (CAS) logic to latch and resolve the row and column addresses and to initiate and terminate read and write operations read and write circuitry to store information in the memory’s cells or read that which is stored there internal counters or registers to keep track of the refresh sequence, or to initiate refresh cycles as needed Output Enable logic to prevent data from appearing at the outputs unless specifically desired. A transistor...

Pin It on Pinterest