JEDEC JESD218B 01-2016 Solid-State Drive (SSD) Requirements and Endurance Test Method.pdf

1、JEDEC STANDARD Solid-State Drive (SSD) Requirements and Endurance Test Method JESD218B.01 (Revision of JESD218B, March 2016) JUNE 2016 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC Bo

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7、 Documents for alternative contact information. Published by JEDEC Solid State Technology Association 2016 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 This document may be downloaded free of charge; however JEDEC retains the copyright on this material. By downloading this file th

8、e individual agrees not to charge for or resell the resulting material. PRICE: Contact JEDEC Printed in the U.S.A. All rights reserved PLEASE! DONT VIOLATE THE LAW! This document is copyrighted by JEDEC and may not be reproduced without permission. For information, contact: JEDEC Solid State Technol

9、ogy Association 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 or refer to www.jedec.org under Standards-Documents/Copyright Information. JEDEC Standard No. 218B.01 -i- SOLID STATE DRIVE (SSD) REQUIREMENTS AND ENDURANCE TEST METHOD Contents 1 Scope 1 2 Reference Documents 1 3 Terms,

10、 definitions, abbreviations, and technical background 2 3.2 Data Error 2 3.3 Data Retention . 2 3.4 Endurance 2 3.5 Endurance failure . 2 3.6 Endurance Rating (TBW rating) 2 3.7 Erase block . 3 3.8 Failure 3 3.9 Functional Failure 3 3.10 Functional Failure Requirement (FFR) 3 3.11 Gigabyte (GB) 3 3.

11、12 Host 3 3.13 Host writes . 3 3.14 Logical Block Address (LBA) . 3 3.15 Non-Volatile Memory (NVM) . 3 3.16 Page 3 3.17 Program/erase cycle (p/e cycle) . 3 3.18 Qualification Family 4 3.19 Retention failure 4 3.20 Solid State Drive (SSD) . 4 3.21 Terabyte (TB) 4 3.22 Uncorrectable Bit Error Rate, or

12、 ratio (UBER) . 4 3.23 Wear leveling . 5 3.24 Workload . 5 3.25 Write amplification factor (WAF) . 5 4 General SSD Ecosystem Factors . 6 4.1 Capacity. 6 4.2 Form Factors 6 5 Application classes and SSD Endurance Rating 6 5.1 Purpose of application classes . 6 5.2 Definition of Application Classes 6

13、5.3 SSD Endurance Rating 7 5.4 Estimation of the SSD endurance rating 7 6 Endurance Test Method . 8 6.1 Direct method 8 6.1.1 Sample Size and Acceptance Criteria 9 6.1.2 Categorization of failures . 11 6.1.3 Endurance Stress Phase 11 6.1.4 High Temperature Retention Stress . 14 6.1.5 Room temperatur

14、e retention evaluation . 15 6.2 Extrapolation method . 16 6.2.1 Short Stroke Extrapolation Method . 16 6.3 Endurance verification given alternative requirements 17 7 Apparatus and Precautions . 17 JEDEC Standard No. 218B.01 -ii- 7.1 Apparatus . 17 7.2 Precautions . 17 8 Summary 18 Annex A (normative

15、): Calculations of Temperature-Accelerated Stress Times 19 Annex B (normative): Assessment of Room-Temperature Data Retention . 21 Annex C (normative): SSD Capacity 23 C.1 SSD Capacity General Overview . 23 C.2 LBA Counts from Advertised Capacity for Low Capacity Drives 24 C.2.1 LBA Counts from Adve

16、rtised Capacity for Low Capacity Drives Overview . 24 C.2.2 LBA Counts from Advertised Capacity for Low Capacity Drives with logical block size of 512 bytes . 24 C.2.3 LBA Counts from Advertised Capacity for Low Capacity Drives with logical block size of 4096 bytes . 24 C.3 LBA Counts from Advertise

17、d Capacity for High Capacity Drives . 24 C.3.1 LBA Counts from Advertised Capacity for High Capacity Drives Overview . 24 C.3 LBA Counts from Advertised Capacity for High Capacity Drives (contd) 25 C.3.1 LBA Counts from Advertised Capacity for High Capacity Drives Overview (contd) . 25 C.3.2 LBA Cou

18、nts from Advertised Capacity for 5xx High Capacity Drives 25 C.3.3 LBA Counts from Advertised Capacity for 4xxx High Capacity Drives 25 Annex D (informative): Estimated Retention Time for Nonstandard Active Use temperatures . 26 Annex E (informative): Estimation of SSD Endurance Rating 27 Annex F (i

19、nformative) - Differences between JESD218B and JESD218A 28 JEDEC Standard No. 218B.01 Page 1 SOLID STATE DRIVE (SSD) REQUIREMENTS AND ENDURANCE TEST METHOD (From JEDEC Board Ballot JCB-16-09, formulated under the cognizance of the JC-64.8 Subcommittee on Solid State Drives (Items 303.19, 303.20, 303

20、.21, 303.22, 303.23, 303.26, 303.27, 303.28, and 303.32).) 1 Scope This standard defines JEDEC requirements for solid state drives. For each defined class of solid state drive, the standard defines the conditions of use and the corresponding endurance verification requirements. Although endurance is

21、 to be rated based upon the standard conditions of use for the class, the standard also sets out requirements for possible additional use conditions as agreed to between manufacturer and purchaser. Qualification of a solid state drive involves many factors beyond endurance and retention, so such qua

22、lification is beyond the scope of this standard, but this standard is sufficient for the endurance and retention part of a drive qualification. This standard applies to individual products and also to qualification families as defined in this standard. The scope of this standard includes solid state

23、 drives based on solid-state non-volatile memory (NVM). NAND Flash memory is the most common form on memory used in solid state drives at the time of this writing, and this standard emphasizes certain features of NAND. The standard is also intended to apply to other forms of NVM. 2 Reference Documen

24、ts The revision of the referenced documents shall be that which is in effect on the date of the qualification plan. JESD22-A117, Electrically Erasable Programmable ROM (EEPROM) Program/Erase Endurance and Data Retention Stress Test JESD47, Stress-Test-Driven Qualification of Integrated Circuits JEP1

25、22, Failure Mechanisms and Models for Semiconductor Devices JESD219, Solid State Devices (SSD) Endurance Workloads SFF-8447, LBA Count for Disk Drives JEDEC Standard No. 218B.01 Page 2 3 Terms, definitions, abbreviations, and technical background 3.1 Cycling pool Erase blocks used by the SSD during

26、read, write, or erase operations at a specific point in time. NOTE The SSD may have additional erase blocks besides those in the current cycling pool that may be used as spares or for other purposes. The cycling pool is typically larger than the user-accessible LBA count. 3.2 Data Error A type of fa

27、ilure in which the drive fails to return correct data to the host. NOTE One data error occurs if a read of a logical sector causes the drive to return an unrecoverable error message or to return incorrect data. Data errors are counted as such even if they are transient. See 6.1.2 for further discuss

28、ion of data errors. 3.3 Data Retention The ability of the SSD to retain data over time. Synonymous with retention in this document. 3.4 Endurance The ability of an SSD to withstand multiple data rewrites. 3.5 Endurance failure A failure that is caused by endurance stressing. NOTE 1 Endurance failure

29、s may be data error (3.1) types or functional failure (3.9) types. NOTE 2 In an endurance stress, some failures may occur that are unrelated to endurance. For example, a solder joint could fail. A failure is considered unrelated to endurance if it was not caused by the endurance stress itself (i.e.,

30、 if it was not caused by the repetitive writing of data to the drive). Such non-endurance failures are not considered as part of endurance verification. NOTE 3 A number of distinct failure mechanisms are responsible for endurance failures, and in general these are accelerated in different ways by te

31、mperature and other adjustable qualification parameters. For example, in floating-gate memories failure may be caused by charge trapping (normally accelerated by lower temperatures) in the charge transfer dielectric or by oxide rupturing (normally accelerated by higher temperatures) in the transfer

32、dielectric or in peripheral dielectrics. For these reasons, endurance may depend on temperature but it is not known a priori whether high temperature is worse than low temperature, or vice-versa. 3.6 Endurance Rating (TBW rating) The number of terabytes that may be written to the SSD such that the S

33、SD meets the requirements defined in 5.2. NOTE 1 Several factors impact the endurance rating including how optimally the wear leveling has been implemented, write amplification factor and the cycling capability of the NAND components. The relationship between TBW, write amplification factor and the

34、wear-leveling efficiency are highly dependent on the workload applied for the characterization of endurance. NOTE 2 The TBW rating may also be expressed in an alternative form called drive-writes-per-day (DWPD), with the assumed lifetime also stated. The value of DWPD is TBW/(C*Y*365), where TBW is

35、the endurance rating in terabytes written, C is the capacity in terabytes, and Y is the lifetime in years that is stated along with the DWPD rating. JEDEC Standard No. 218B.01 Page 3 3.7 Erase block The smallest addressable unit for erase operations, typically consisting of multiple pages. 3.8 Failu

36、re The noncompliance of an SSD to the electrical or physical requirements specified for the device. NOTE Failures may be permanent or transient. For the purpose of this standard, a permanent failure is an SSD that fails sometime during a reliability stress and continues to fail at the final test at

37、the end of that same stress. A transient failure is an SSD that fails during a reliability stress but passes in the final test at the end of that stress. 3.9 Functional Failure A failed drive that fails to function properly in a way that is more severe than having a data error. NOTE See 6.1.2 for di

38、scussion of functional failures. 3.10 Functional Failure Requirement (FFR) The allowed cumulative functional failures over the TBW rating. See 5.2. 3.11 Gigabyte (GB) Approximately equal to 109 bytes when used in reference to SSD capacity. See Annex C (normative): SSD Capacity. 3.12 Host The compute

39、r system, test system, or other device, which writes data to and reads data from the SSD. 3.13 Host writes Data transmitted through the primary SSD interface to be written to the SSD. 3.14 Logical Block Address (LBA) The logical address used to reference a data sector (block) in the drive. NOTE 1 LB

40、A is synonymous with the data sector itself. NOTE 2 Block in the drive is a logical construct separate from that of an erase block in the NVM. 3.15 Non-Volatile Memory (NVM) A memory which retains data after the power is turned off. NOTE 1 Non-volatile memories considered in this standard are capabl

41、e of being electrically rewritten. 3.16 Page A sub-unit of an erase block consisting of a number of bytes which can be read from and written to in single operations, through the loading or unloading of a page buffer and the issuance of a program or read command. 3.17 Program/erase cycle (p/e cycle)

42、The writing of data to one or more pages in an erase block and the erasure of that block, in either order. JEDEC Standard No. 218B.01 Page 4 3.18 Qualification Family A group of SSD products which differ only in storage capacity and in minor design details that are directly related to the capacity d

43、ifferences. NOTE To be considered part of the same qualification family, SSD products must use the same nonvolatile memory products, or different nonvolatile memory products that are themselves part of the same component qualification family (defined in JESD47). The SSD products must also use the sa

44、me controller and the same firmware, except to the extent that the firmware requires different settings to support the different capacities of the drives. The SSD products must also have the same ratio of TBW specification to capacity; for example, a 100 GB drive with a 100 TBW specification could b

45、e in the same family as a 50 GB drive with a 50 TBW specification. Due to the complexity of SSD designs, it is beyond the scope of this specification to completely define what constitutes a qualification family. The burden of proof falls upon the SSD manufacturer who chooses to use the qualification

46、 family concept. 3.19 Retention failure A data error occurring when the SSD is read after an extended period of time following the previous write. NOTE A number of distinct failure mechanisms are responsible for retention failures, and in general these are accelerated in different ways by temperatur

47、e and other adjustable qualification parameters. For example, in floating-gate memories, failure may occur due to defects that allow charge to leak through the transfer dielectric or by the detrapping of charge in the transfer dielectric; the former can be weakly accelerated or even decelerated by h

48、igh temperature, and the latter can be highly temperature accelerated (see JEP122). For these reasons, retention may depend on temperature but it is not known a priori whether high temperature is worse than low temperature, or vice-versa. 3.20 Solid State Drive (SSD) A solid state drive (SSD) is a n

49、on-volatile storage device. A controller is included in the device with one or more solid state memory components. The device should use traditional hard disk drive (HDD) interfaces (protocol and physical) and form factors. 3.21 Terabyte (TB) For the purpose of this standard, a terabyte is equal to 11012 bytes. 3.22 Uncorrectable Bit Error Rate, or ratio (UBER) A metric for the rate of occurrence of data errors, equal to the number of data errors per bits read. Mathematically, re a db i t sofn u m b e r e rro rsd a t aofn u m b e rU B E R (1) NOTE Although the UBER concept is in wi