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บทสรุปผมไม่สรุป แต่บทความนี้ ดูเหมือนว่าจะสนับสนุนความคิดท่านแมว
Nand flash has become a staple in all facets of today's consumer electronics. In accordance with its popularity and the economies of scale,
many types of Nand flash have been developed in order to reduce costs and to cater to specific product applications or designs. Interestingly,
in the highly competitive and ever improving USB memory drive industry, all major forms of Nand flash can be analyzed: TSOP, BGA, LGA, and COB. Lets have a look, shall we?
The most standard form of Nand Flash is TSOP (Thinner Small Outline Packaging, 12mm*18.2mm size), which features 48 pins on the 2 shorter sides of the rectangular IC.
TSOP flash is attached onto the surface of a printed circuit board from the lead pins, by either SMT or hand soldering. TSOP was the first packaged form of Nand flash IC,
and all other forms being developed afterwards. With the use of TSOP flash, memory applications can be operated frequently with very stable and error-free characteristics.
The yield rate for TSOP is high, packaging price is cheap, and can easily be de-soldered for replacement of faulty IC in the event of a RMA.
With the use of lead to solder the IC onto a PCB, the contact area between the two is minimal, which equates to low heat transfer and adds to the reliability of its function.
By far the vast majority of flash IC used in consumer electronics are TSOP because of its availability, easy processing, and lower RMA cost.
BGA (Ball Grid Array, 10.5mm*13mm size most common), is a form of packaging that is surface mounted to the PCB via the solder balls on its underside.
The BGA format can support thousands of balls (or connections), meet high input-output (I/O) requirements, and because of its short distance between the array/die/board design,
BGA offers very effective heat dissipation and electrical performance. Using ball grid array packaging, under the same capacity, the physical size is typically only 1/3 of TSOP,
and can achieve higher speeds. As is the case with LGA as well, BGA take up less space because the IC is attached directly to the PCB by the bottom of the IC.
Without the need to attach by side lead pins (TSOP), ball and land grid array IC can fit into tighter spaces and which is beneficial for mobile product applications.
Flash BGA is mounted on a main board by soldering the 100-ball bottom area, available in standard square or rectangular body sizes, and is commonly used for Solid State Drives (SSD).
LGA (Land Grid Array, 14mm*18mm size) packaging is a type of configuration where neither lead pins nor solder balls are used.
Metal pads are arranged in a grid formation over the bottom surface similar to BGA, but more densely packed. Like BGA semiconductor packaging,
LGA is also suitable for use in high I/O applications and offers stable voltage input.
A key differing characteristic of LGA is its ability to stack many silicon ink die to form greater memory capacities in the same physical form. In mobile phone applications where space is a premium,
a single LGA can be used for 16GB or 32GB, as evident in Apple's iPhone. With TSOP, ink die stacking is limited to 2, while LGA can go up to 4 or 5,
making land grid array a more feasible packaging solution for high memory capacities in tight space applcations.
COB (Chip On Board, size depends) is used instead of the standard rectangular shape packaged IC and in USB drive applications can be used for Nand flash or USB controller.
The process consists of first attaching or mounting the die to the PCB, then wirebonding, and lastly encapsulating the die/wires in an epoxy resin that is left to cure into a hardened state.
When hardened, the exterior is very similar in scope to the black housing of an IC. This COB epoxy process can be applied for almost all IC applications and alleviates much of the packaging process as well as SMT,
in order to save much time and cost. Generally, COB Nand flash is the cheapest out of all 4 styles of flash discussed. However,
due to the use of epoxy to encapsulate, in the case of RMA or problems with the flash memory, the die cannot be fixed or replaced and must be considered obsolete.
With the consideration to its high RMA cost, COB flash is typically only used in lower valued memory products such as USB drives and SD cards.
ต้นฉบับ
ว่าจะใส่ Quote แล้วกลัวตัวเล็กอ่านยาก
เครดิตต้นฉบับด้านล่างครับ
บทสรุปผมไม่สรุป แต่บทความนี้ ดูเหมือนว่าจะสนับสนุนความคิดท่านแมว
Nand flash has become a staple in all facets of today's consumer electronics. In accordance with its popularity and the economies of scale,
many types of Nand flash have been developed in order to reduce costs and to cater to specific product applications or designs. Interestingly,
in the highly competitive and ever improving USB memory drive industry, all major forms of Nand flash can be analyzed: TSOP, BGA, LGA, and COB. Lets have a look, shall we?
The most standard form of Nand Flash is TSOP (Thinner Small Outline Packaging, 12mm*18.2mm size), which features 48 pins on the 2 shorter sides of the rectangular IC.
TSOP flash is attached onto the surface of a printed circuit board from the lead pins, by either SMT or hand soldering. TSOP was the first packaged form of Nand flash IC,
and all other forms being developed afterwards. With the use of TSOP flash, memory applications can be operated frequently with very stable and error-free characteristics.
The yield rate for TSOP is high, packaging price is cheap, and can easily be de-soldered for replacement of faulty IC in the event of a RMA.
With the use of lead to solder the IC onto a PCB, the contact area between the two is minimal, which equates to low heat transfer and adds to the reliability of its function.
By far the vast majority of flash IC used in consumer electronics are TSOP because of its availability, easy processing, and lower RMA cost.
BGA (Ball Grid Array, 10.5mm*13mm size most common), is a form of packaging that is surface mounted to the PCB via the solder balls on its underside.
The BGA format can support thousands of balls (or connections), meet high input-output (I/O) requirements, and because of its short distance between the array/die/board design,
BGA offers very effective heat dissipation and electrical performance. Using ball grid array packaging, under the same capacity, the physical size is typically only 1/3 of TSOP,
and can achieve higher speeds. As is the case with LGA as well, BGA take up less space because the IC is attached directly to the PCB by the bottom of the IC.
Without the need to attach by side lead pins (TSOP), ball and land grid array IC can fit into tighter spaces and which is beneficial for mobile product applications.
Flash BGA is mounted on a main board by soldering the 100-ball bottom area, available in standard square or rectangular body sizes, and is commonly used for Solid State Drives (SSD).
LGA (Land Grid Array, 14mm*18mm size) packaging is a type of configuration where neither lead pins nor solder balls are used.
Metal pads are arranged in a grid formation over the bottom surface similar to BGA, but more densely packed. Like BGA semiconductor packaging,
LGA is also suitable for use in high I/O applications and offers stable voltage input.
A key differing characteristic of LGA is its ability to stack many silicon ink die to form greater memory capacities in the same physical form. In mobile phone applications where space is a premium,
a single LGA can be used for 16GB or 32GB, as evident in Apple's iPhone. With TSOP, ink die stacking is limited to 2, while LGA can go up to 4 or 5,
making land grid array a more feasible packaging solution for high memory capacities in tight space applcations.
COB (Chip On Board, size depends) is used instead of the standard rectangular shape packaged IC and in USB drive applications can be used for Nand flash or USB controller.
The process consists of first attaching or mounting the die to the PCB, then wirebonding, and lastly encapsulating the die/wires in an epoxy resin that is left to cure into a hardened state.
When hardened, the exterior is very similar in scope to the black housing of an IC. This COB epoxy process can be applied for almost all IC applications and alleviates much of the packaging process as well as SMT,
in order to save much time and cost. Generally, COB Nand flash is the cheapest out of all 4 styles of flash discussed. However,
due to the use of epoxy to encapsulate, in the case of RMA or problems with the flash memory, the die cannot be fixed or replaced and must be considered obsolete.
With the consideration to its high RMA cost, COB flash is typically only used in lower valued memory products such as USB drives and SD cards.
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