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Unit 1 OMT.pptx

  1. Unit 1 OMT Memory
  2. SRAM • SRAM (static RAM) is a type of random access memory (RAM) that retains data bits in its memory as long as power is being supplied. Unlike dynamic RAM (DRAM), which must be continuously refreshed, SRAM does not have this requirement, resulting in better performance and lower power usage. However, SRAM is also more expensive than DRAM, and it requires a lot more space.
  3. For example • Time in market: 1990s to present • Popular products using SRAM: Digital cameras, routers, printers, LCD screens It might be part of a RAM digital-to-analog converter (RAMDAC) on a computer's video or graphic card. It might also be used in a disk drive as buffer cache, in a peripheral such as a printer or LCD display, or in a network device such as router or switch. • SRAM can be found in other devices ways as well. For example, SRAM chips are often used in cell phones, wearables and other consumer electronics. They might also be embedded in medical products, which can include anything from hearing aids to body area networks that include multiple devices embedded in the body. In addition, SRAM is used in toys, appliances, automobiles, industrial equipment and a wide range of IoT devices.
  4. States of SRAM : • It can be in 3 states, namely – • Standby – It is a condition in SRAM when SRAM’s circuitry is sitting idle and no work is given to a particular SRAM. It can underutilize the capacity of the resources available. • Reading – It is a condition in SRAM when the data has been requested to be fetched. It puts the SRAM’s circuitry in working condition. • Writing – It is a c condition in SRAM when the data has to be updated or overwritten stored in Async SRAM. This state will also put SRAM’s circuitry in working condition.
  5. Types of SRAM • Non-volatile SRAM • (nvSRAM) has standard SRAM functionality, but they save the data when the power supply is lost, ensuring preservation of critical information. nvSRAMs are used in a wide range of situations – networking, aerospace, and medical, among many others – where the preservation of data is critical and where batteries are impractical.
  6. 2.Asynchrous SRAM • First of all, let us see what is meant by asynchronous here. The devices that do not depend on external clock pulse for their working, these devices are called asynchronous devices, and the SRAM which does not depend on an external clock for its working is known as asynchronous SRAM.
  7. By feature • (Zero bus turnaround) (ZBT) – the turnaround is the number of clock cycles it takes to change access to the SRAM from write to read and vice versa. The turnaround for ZBT SRAMs or the latency between read and write cycle is zero. • Sync Bust (syncBurst SRAM or synchronous-burst SRAM) – features synchronous burst write access to the SRAM to increase write operation to the SRAM. • DDR SRAM – synchronous, single read/write port, double data rate I/O. • Quad Data Rate SRAM – synchronous, separate read and write ports, quadruple data rate I/O.
  8. Dynamic RAM(DRAM) • DRAM, or dynamic random access memory, implies, this form of memory technology is a type of random access memory. It stores each bit of data on a small capacitor within the memory cell. The capacitor can be either charged or discharged and this provides the two states, "1" or "0" for the cell. • Since the charge within the capacitor leaks, it is necessary to refresh each memory cell periodically. This refresh requirement gives rise to the term dynamic - static memories do not have a need to be refreshed.
  9. • The advantage of a DRAM is the simplicity of the cell - it only requires a single transistor compared to around six in a typical static RAM, SRAM memory cell. In view of its simplicity, the costs of DRAM are much lower than those for SRAM, and they are able to provide much higher levels of memory density. However the DRAM has disadvantages as well, and as a result, most computers use both DRAM technology and SRAM, but in different areas.
  10. SDRAM • Synchronous Dynamic Random Access Memory (SDRAM)- ‘Synchronous’ relates to the behavior of the Dynamic Random Access Memory type that synchronizes with the clock system of the computer, thus making it easier to manage it quicker.
  11. • SDRAM has undergone changes and the recently updated version delivers better performance. Given below are some generations of SDRAM: – DDR SDRAM( double data rate (DDR) synchronous dynamic random-access memory (SDRAM)) – DDR2 SDRAM – DDR3 SDRAM – DDR4 SDRAM – DDR5 SDRAM