TABLE OF CONTENTS Objective: Virtually any digital system requires some kind of memory, so understanding how memories are built, their main features, and how they work is indispensable. Volatile memories are described in this chapter, while nonvolatile ones are described in the next. The following volatile types are included below: SRAM (regular, DDR, and QDR), DRAM, SDRAM (regular, DDR, DDR2, and DDR3), and CAM.
Chapter Contents
| 16.1 | Memory Types |
| 16.2 | Static Random Access Memory (SRAM) |
| 16.3 | Dualand Quad Data Rate (DDR, QDR) SRAMs |
| 16.4 | Dynamic Random Access Memory (DRAM) |
| 16.5 | Synchronous DRAM (SDRAM) |
| 16.6 | Dual Data Rate (DDR, DDR2, DDR3) SDRAMs |
| 16.7 | Content-Addressable Memory (CAM) for Cache Memories |
| 16.8 | Exercises |
The enormous need in modern applications for large and efficient solid-state memory has driven MOS technology to new standards, so a discussion on MOS technology would not be complete without the inclusion of memories.
Memories are normally classified according to their data-retention capability as volatile and nonvolatile. Volatile memory is also called RAM (random access memory), while nonvolatile is also (for historic reasons) called ROM (read only memory). Within each of these two groups, further classification exists, as shown in the lists below. Some promising next-generation memories are also included in this list and will be seen in Chapter 17.
Volatile memories (Chapter 16):
SRAM (static RAM)
DDR and QDR (dual and quad data rate) SRAM
DRAM (dynamic RAM)
SDRAM (synchronous DRAM)
DDR/DDR2/DDR3 SDRAM (dual data rate SDRAM)
CAM (content-addressable memory) for cache memories
Nonvolatile memories...
