What Is The Full Form Of DDR?
The full form of DDR is Double Data Rate.
DDR is a technique in computing in which the computer bus transfers data on both falling and rising edges of a clock cycle/signal at a double rate. It is also called dual-pumped, double-transition, and double-pumped. This technique allows sending of 2 signals per clock cycle.
The Double Data Rate is an advanced version of SDRAM. DDR-SDRAM is sometimes called the SDRAM II, and its speed of data transfer is twice as compared to regular SDRAM chips. It is because DDR can receive and send signals twice in every clock cycle. Due to the efficient operation of DDR-SDRAM, it uses up less power- making it great for notebook computers.
Working of DDR
The easiest way to design a clocked electronic circuit is by making it perform one transfer per clock cycle (rise and fall). The SDR technique uses it. This step, however, requires the clock signal to change twice per cycle, whereas the data lines are capable of changing at most once per cycle. Thus, when it operates at a higher bandwidth, the clock frequency gets constrained by signal integrity limitations. Using both the edges of the clock helps the data signals operate with a similar limiting frequency while still doubling their transmission rate.
The technique used in this process is an improvement over single data rate (SDR)- its predecessor and an improved version named quad data rate (QDR) has succeeded it.
Characteristics of DDR
- DDR transmits data and info twice per wave (clock/cycle)- first at the rising edge, then at the falling edge of that clock cycle.
- It operates at a similar frequency as compared to the clock cycle.
- Every clock cycle follows a unidirectional flow of data.
- The DDR SDRAM technology is new and consumes less power than its predecessor SDRAM.
- The SDRAM expends 3.3 V, while the DDR SDRAM expends 2.6 V.
- The same frequencies go for both DDR and SDRAM- the difference being DDR uses both the clock edges, while SDRAM uses only one.
Applications of DDR
One can apply the DDR technique in those applications that require high-speed for data transfer, such as:
- DDR is a suitable technique for building volatile components for a computer (RAM)- commonly referred to as double data rate synchronous dynamic random access memory (DDR SDRAM). It got a lot of success in the field. And thus, the same technique came into use in the later iterations of the technology- DDR2 SDRAM, DDR3 SDRAM, DDR4 SDRAM.
- It works well in analog-to-digital converters.
- The DDR technique is also useful for including volatile storage capacities in Graphic Cards (graphic processors). It is known as graphics double data rate (GDDR). This technology is tailored to go along with video cards.
- DDR is a prerequisite in the bus of some microprocessors like AMD’s Athlon64 series. It allows data transmission at a faster rate to and from the CPU.
Benefits of DDR
- It helps a user obtain higher levels of transmission speeds.
- DDR reduces the total number of cycles required for performing any task.
- It reduces the required component cost.
- DDR also allows for shorter form factor computing devices.
Limitations of DDR
- DDR works slower when compared to the QDR technique, which is its successor.
- Any device that accommodates and works according to the DDR technique produces more heat.