This lesson introduces dynamic random-access memory (DRAM), its basic storage principle, and its role in computers and other digital devices. Understanding DRAM helps explain how systems provide large amounts of affordable working memory.
Dynamic random-access memory (DRAM) is semiconductor memory in which each bit is held in a memory cell. The most common cell uses one transistor and one capacitor, often described as a 1T1C cell. The transistor controls access to the capacitor, while the capacitor holds an electrical charge.
All flashcards
What is a typical 1T1C DRAM cell?
A cell with one access transistor and one capacitor that stores a bit as electrical charge.
What is DRAM data remanence?
The limited persistence of data in DRAM after power or refresh is removed; it is not dependable storage.
How does a folded-bitline array reduce noise?
It routes paired bit-lines close together, helping them experience similar noise.
What is embedded DRAM (eDRAM)?
DRAM integrated into a logic chip, such as a processor or system-on-chip.
What does page mode improve in DRAM?
It avoids repeatedly closing and reopening a row when accessing multiple columns in that row.
Quiz questions
What do DRAM sense amplifiers do after a selected cell slightly changes a bit-line voltage?Answer: They amplify the small voltage difference into stable logic levels.
Why is a DRAM read described as destructive?Answer: Charge sharing with the bit-line disturbs the cell's stored charge.
When does DDR SDRAM transfer data?Answer: On both edges of the clock signal.
What can a common SECDED Hamming code do?Answer: Correct a single-bit error and detect a double-bit error.
Why can spare rows or columns improve DRAM manufacturing yield?Answer: Remapping can replace defective regions with functioning spare regions.