For a smartphone, any component can affect the overall performance and experience of the phone, processor, memory, flash, screen, and more. However, for the novice users who are just getting started, when discussing the terms UFS2.0, eMMC 5.1, and LPDDR4 with other netizens, they may be confused: What are these?
To understand the meaning and difference between the words UFS2.0, eMMC 5.1, and LPDDR4, the first thing to understand is the two confusing concepts of mobile phone memory and flash memory.
RAM
Mobile phone memory (RAM, random access memory), also known as "random access memory", is an internal memory that exchanges data directly with the CPU, also called main memory (memory). It can be read and written at any time and is fast, often acting as a temporary data storage medium for operating systems or other running programs. Such a memory will lose its stored content when it is powered off, so it is mainly used to store programs for short-term use. Talking about people is what we often call mobile phone running memory.
On the PC platform, memory has experienced the development of SIMM memory, EDO DRAM memory, SDRAM memory, Rambus DRAM memory, DDR memory, and nowadays it has spread to DDR4 memory, and the LPDDR RAM used on mobile phones is "low power double data rate memory. Abbreviation, compared to the DDR4 memory of the desktop platform, LPDDR4 for mobile platforms, which can bring equivalent performance (speed) while taking into account less energy consumption.
Flash memory
Flash Memory is a long-lived non-volatile memory that retains stored data information even in the event of a power failure. It does not lose data even when power is turned off. Data deletion is not in a single byte. The unit is in units of fixed blocks (NOR Flash is byte storage.), and the block size is generally 256KB to 20MB. In layman's terms, it is equivalent to a hard disk in a computer. The running memory does not retain the stored data after the power is turned off. To keep the data from being lost for a long time, it is necessary to write the data from the memory to the hard disk. For desktop devices such as computers, we can plug in a hard drive, and for mobile devices such as mobile phones, it is obviously unrealistic.
Thus, in 1984, Toshiba’s inventor, Nguyen Fujio, first proposed the concept of fast flash memory (herein referred to as flash memory). The feature is non-volatile, its recording speed is also very fast, and at the same time small size, so it was widely used in digital cameras, handheld computers, MP3, mobile phones and other small digital products. Intel was the first company in the world to produce flash memory and put it on the market. At the time, it was NOR flash memory. Later, Hitachi developed NAND flash memory in 1989, gradually replacing NOR flash memory. It is worth mentioning that the ROMs of SSDs and mobile phones widely used in PCs today are essentially a family of NAND flash memories.
UFS and eMMC
Through the above brief introduction, you can understand the difference between memory and flash memory. So let's take a look at the flash specifications eMMC and UFS. Among them, eMMC is called "embedded Multi Media Card", which is an embedded multimedia memory card. It is an in-line memory standard specification established by the MMC Association for products such as mobile phones or tablets. Simply put, on the basis of the original built-in memory, a control chip is added, and then packaged in a unified manner, and a standard interface is reserved for the mobile phone customer to use directly. This storage medium was used by all major smartphones and tablets before 2015.
In 2011, the Joint Electron Device En gineering Council (JEDEC) released the first generation of Universal Flash Storage (UFS) standard, the predecessor of UFS 2.0. However, the first generation of UFS was not popular and did not have a significant impact on the eMMC standard.
In 2013, JEDEC released the UFS 2.0 next-generation flash storage standard in September of that year. The UFS 2.0 flash read and write speed can theoretically reach 1400MB/s, which not only has a greater advantage than eMMC, but it can even be used on computers. The SSD used is also dwarfed. So gradually replaced eMMC in the high-end equipment market, becoming the mainstream standard for mobile devices. In fact, UFS 2.0 has two versions, one of which is HS-G2, which is the current UFS 2.0. However, another version is HS-G3, which can be called UFS 2.1, and its data read speed will be 1.5G/s, which is twice that of UFS 2.0.
So what is the difference between UFS and eMMC? The difference is that the UFS 2.0 flash specification uses a new standard, which uses a serial interface, much like PATA, SATA conversion. And it supports full-duplex operation, simultaneous read and write operations, and also supports instruction queues. In contrast, eMMC is half-duplex, reading and writing must be performed separately, instructions are also packaged, and it is already slightly inferior in speed. Moreover, the UFS chip not only has a fast transmission speed, but also consumes half as much power as eMMC 5.0. It can be said that it is an ideal match for the current and future flagship mobile phone flash memory.
DDR and LPDDR
DDR=Dual Data Rate Double Rate Synchronous Dynamic Random Access Memory. Strictly speaking, DDR should be called DDR SDRAM. People used to call it DDR. SDRAM is the abbreviation of Synchronous Dynamic Random Access Memory, which is synchronous dynamic random access memory. DDR SDRAM is the abbreviation of Double Data Rate SDRAM, which means double-rate synchronous dynamic random access memory. SDRAM transmits data only once in one clock cycle, which is data transmission during the rising period of the clock; while DDR memory transmits data twice in one clock cycle, which can be transmitted once during the rising and falling phases of the clock. Data, hence the so-called double rate synchronous dynamic random access memory. DDR memory can achieve higher data rates at the same bus frequency as SDRAM.
What is LPDDR? Its full name is Low Power Double Data Rate SDRAM, which is a kind of DDR, also known as mDDR (Mobile DDR SDRAM). It is the JEDEC Solid State Technology Association of the United States for low power consumption. The communication standard established by memory is known for its low power consumption and small size, and is specifically used for mobile electronic products.
DDR memory has gone from DDR to DDR2, DDR3 and DDR4, and the era of DDR5 has not yet arrived. From DDR and DDR2 to DDR3, the frequency is higher and the voltage is lower, and the delay is also increasing, slowly changing the memory subsystem. The most important mission of DDR4 is to increase the frequency and bandwidth, and each pin can provide 2Gbps (256MB/s) bandwidth, with a frequency of up to 4266MHz, memory capacity up to 128GB, normal operating voltage can be reduced to 1.2V, 1.1V.
The operating voltage (operating voltage) of LPDDR is lower than the standard voltage of DDR. From the first generation LPDDR to today's LPDDR4, each generation of LPDDR doubles the internal read size and the external transfer speed. Among them, LPDDR4 can provide 32Gbps bandwidth, and the input/output interface can transmit data up to 3200Mbps and the voltage drops to 1.1V. As for the latest LPDDR4X, the same as LPDDR4, it saves extra power by reducing the I/O voltage to 0.6 V instead of 1.1 V, which is more power-saving.
TAG: UFS EMMC LPDDR
