The board becomes more and more empty, but it may not be shrinking. From the PCB layout to see the development of solid-state drive integration

　　PCB boards are getting empty (the number of components is decreasing), which is not necessarily a bad thing. Just like the so-called lightning protection chips commonly found on computer motherboards in the past, the lightning protection functions of the motherboard have now been integrated into the components of the RJ45 network interface. In the past few years, low-end motherboard manufacturers used independent lightning protection chips (network filters) as their selling point. Now players have seen through this trick of treating backwardness as advanced.

　　Solid State Drive Multilayer Circuit Board

　　Disassembling a contemporary most advanced 3D flash memory SATA solid state drive, it is likely to see a few flash memory particles, a master chip without DRAM cache. Nowadays, no external cache solution has become the standard configuration of SATA solid-state hard drives. With a small amount of built-in SRAM cache and optimized FTL algorithm, a non-DRAM cache solid state drive such as the Toshiba TR200 can also exert excellent random read and write performance.

　　Solid State Disk PCB Board

　　Back to three years ago, Toshiba's first-generation 2DTLC solid-state drive Q300, which was just launched at that time, uses an 8-channel master with DRAM cache. The densely arranged flash memory particles make the entire PCB appear very full, but its performance with TR200 is almost There is no difference, even the TR200, which is not as empty as the board in some respects.

　　Solid State Disk PCB Board

　　The Toshiba RC100, which came out this year, refreshed the public’s impression of solid state drives. There is only one chip on the M.22242 mini PCB, which is obviously the smallest M.2 solid state drive, but it still looks "empty":

　　Solid State Drive Circuit Board

　　We compare the disassembly diagram of RC100 with a classic SATA solid state drive, and we will find that in addition to the DRAM cache, several other components have disappeared:

　　Solid State Drive Circuit Board

　　First is the small black chip in the red box above-serial NOR flash memory. With a capacity of only about 1MB, it carries the role of firmware storage in the solid state drive, similar to the BIOS chip on the motherboard. The main control of contemporary solid-state hard drives has its own ROM space, and the independent NOR flash memory chip is no longer needed.

　　The external crystal oscillator in the yellow box in the lower right corner of the main control is another disappearing component in the solid state drive. At present, the crystal oscillator on the SSD of most major manufacturers has been integrated into the chip.

　　The external crystal oscillator is a solid state drive

　　Toshiba RC100 has once again made a major integration of the main control and flash memory. They are packaged in a single particle, which reduces PCB wiring and makes the overall solid state drive more compact.

　　SSD

　　In addition to M.22242, it can also be made into a smaller M.22230 specification, and even directly integrated into the motherboard of a thin and light notebook computer.

　　Solid State Drive PCBA

　　The Toshiba BiCS3 flash memory used in the RC100 is manufactured using a 64-layer 3D stacking process. The capacity of a single die is 256Gb. Only 16 flash memory dies and the main controller need to be packaged together to obtain a 480GB NVMe solid state drive with only one chip.

　　The RC100, which is an NVMe protocol solid state drive, also does not have an external DRAM cache. Through the HostMemoryBuffer host memory acceleration feature of the NVMe protocol, the RC100 only needs to borrow 38MB of host memory to be as efficient as an NVMe solid state drive with external DRAM cache. Work.

　　With the mass production of 96-layer BiCS4 flash memory and QLC technology, single-chip NVMe solid state drives will have the opportunity to achieve 1.33TB of massive storage space in the future. Do you still miss the old solid state drives with densely packed components?

Read recommendations:

Six-layer Immersion Gold Board (BGA)

Laminate copper-based PCB after 4L (sample)

Six-layer Immersion Gold Board (BGA)

DIP plugin

Explore the meaning of each layer of the multilayer circuit board