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Solutions for Solid State Storage
Applications
© 2019 KEMET Corporation
Cloud InfrastructureSolid State Drives
© 2019 KEMET Corporation
Market Driver
© 2019 KEMET Corporation
Common Terms or Expressions
• Power Loss Imminent
• Power Loss Protection
• Data-Loss Protection
• Data Persistence
• Hold-up
• Last Gasp
© 2019 KEMET Corporation
Hold-up
𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑎𝑛𝑐𝑒 =𝐶ℎ𝑎𝑟𝑔𝑒
𝑉𝑜𝑙𝑡𝑎𝑔𝑒
𝐶ℎ𝑎𝑟𝑔𝑒 = 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 ∗ 𝑇𝑖𝑚𝑒 𝑄 = 1.8 𝐴 ∗ 15 𝑚𝑠 = 0.027 𝐶𝑜𝑢𝑙𝑜𝑚𝑏
𝐶 =0.027 𝐶𝑜𝑢𝑙𝑜𝑚𝑏
12 𝑉𝑜𝑙𝑡𝑠= 2.25 𝑚𝐹
• Hold-up
‒ Momentary, unexpected power interruption
‒ In the event that external power to the SSD
is lost, it will switch to a bank of charged
capacitors to supply power for the last writes
in progress and shut down elegantly
• Hold-up time
‒ The time a power supply unit will
operate after a power failure
‒ 15 – 25 milliseconds
𝐸𝑛𝑒𝑟𝑔𝑦 =1
2𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑎𝑛𝑐𝑒(𝑉𝑜𝑙𝑡𝑎𝑔𝑒1
2 − 𝑉𝑜𝑙𝑡𝑎𝑔𝑒22)
𝐸 =1
2(0.00225 𝐹𝑎𝑟𝑎𝑑)(12 𝑉𝑜𝑙𝑡𝑠 − 6 𝑉𝑜𝑙𝑡𝑠) = 6.75 MilliJoules
© 2019 KEMET Corporation
Product Category Requirements
Consumer(Tablets, Cameras, Mobile Devices)
Client(Netbook, Notebook, Ultrabook, Desktop)
Enterprise(HPC, Datacenter Server)
Data Loss Prevention Becomes More Critical
© 2019 KEMET Corporation
Client vs. Enterprise SSD
Client • Single user or application access
• Higher tolerable delta between
minimum and maximum response
time (or latency) on any user of
system action.
• Active Use: 40°C, 8 hrs/day
• Retention Use: 30°C, 1 year
• 1 unrecoverable bit error at a ratio
of 1 bit error for every 1 quadrillion
bits
• 20/80 (20% of active time,
80% in idle or in sleep mode)
duty cycle
Enterprise • Must be accessible with least
amount of latency.
• Involve large number of users
needing to access same data
simultaneously with no degradation
in response time.
• Active Use: 55°C, 24 hrs/day
• Retention Use: 40°C, 3 months
• 1 unrecoverable bit error at a ratio
of 1 bit error for every 10
quadrillion bits
• Higher level of power loss
protection
• 24 x 7 duty cycle
Performance Reliability Endurance
© 2019 KEMET Corporation
Data Status
At-Rest In-Flight
• Data saved to the storage media
• Data from transmitted from host to storage device
• Writes in progress, but not complete
• Buffered data (before stored to NAND)
© 2019 KEMET Corporation
Enterprise SSD Example
Hold-up CapacitorsProvides sufficient energy to transfer in-flight data to non-volatile memory during power loss.
DRAM Cache/BufferUsed for speed matching and to increase data throughput. Requires power to retain data.
InterfaceBetween the host computer and the SSD Device
Controller• Provides level interfacing and firmware execution. • Includes an embedded processor, electrically erasable data
firmware ROM, system RAM, support for external RAM (usually DDR/DDR2/DDR3/DDR4 as SDRAM), flash component interface (usually a standard interface such as Open NAND Flash Interface - ONFI), Host electrical interface (SATA, SAS, USB, or combination), error correction code (ECC) circuitry, wear leveling/TRIM, and security features.
NAND Flash MemoryStorage of data on SSD device. Does not require power to retain data.
© 2019 KEMET Corporation
Data Flow Illustration
Transmit
Store
Write
• Host starts transmitting data
• Data stored in RAM buffer
• Data is saved in NAND
© 2019 KEMET Corporation
Common Form Factors
Drives1.8”, 2.5” (various heights)
Add-In CardsFull or Half Height, Low Profile,
Full or Half Length
ModulesM.2, U.2
Form factor impacts space requirements for hold-up capacitors.
© 2019 KEMET Corporation
Capacitor Types
Ceramic (MLCC)
✓ Loses capacitance with temperature, voltage, and time (aging)
✓ Typically X5R or X7R
✓ Wide ranging footprints and heights
Supercapacitor
Aluminum
Electrolytic
KO-CAP™
(Tantalum Polymer)
✓ Flat packaging aka “prismatic”
✓ Rated voltages 3-5 volts
✓ Capacitance loss during operational life
✓ Surface mount, snap-in or press-fit
✓ Large capacitance and high rated voltages
✓ Capacitance loss during operational life
✓ Solid capacitor (no electrolytic)
✓ Known as “Polymer Ta” and by trade names
✓ Large capacitance and relatively high rated voltages
Aluminum
Polymer
✓ Surface mount, radial
✓ Ultra-low impedance
✓ High ripple current
✓ Stable characteristics in very low temperature ranges
© 2019 KEMET Corporation
Ta Polymer (Solid)
Al Electrolytic (Wet)
Supercapacitor (Wet)
X5R/X7R Ceramic (Solid)
Length x Width(mm x mm)
3.2 x 1.63.5 x 2.86.0 x 3.27.3 x 4.37.3 x 6.0
4.3 x 4.35.3 x 5.36.6 x 6.68.3 x 8.3
10.3 x 10.3
5x65x7
6.3x5.46.3x76.3x8
6.3x9.78x7.58x9.7
10x12.6
21 x 14
1.00 x 0.501.60 x 0.802.00 x 1.253.20 x 1.603.20 x 2.504.70 x 2.004.50 x 3.204.50 x 6.405.70 x 5.005.60 x 6.40
Height (mm) 1.0 to 4.3 5.8 to 10.3 5.3 to 10.3 2.2 to 3.5 0.50 to 2.50
Capacitor Dimensions
Aluminum
Polymer
© 2019 KEMET Corporation
Ta Polymer
(Solid)
Al Electrolytic
(Wet)
Supercapacitor
(Wet)
X5R/X7R
Ceramic (Solid)
Rated Voltage 6.3 V – 35 V 1 6.3 V – 35 V 1 2.5 V – 35 V 1 4.2 V 6.3 V – 35 V 1
Derating
Recommendations
≤ 10 Vr: 90% Vr
> 10 Vr: 80% Vr
No derating No derating Down to 3.0 V No derating 2
Voltage Ratings
1 Voltage Limited to 35 V since regulators for Enterprise SSDs tend to be rated2 Voltage Ceramic capacitors do not de-rate for reliability, but consider capacitance loss with applied voltage.
Aluminum
Polymer
© 2019 KEMET Corporation
Ta Polymer
(Solid)
Al Electrolytic
(Wet)
Supercapacitor
(Wet)
X5R/X7R Ceramic
(Solid)
Voltage
Temperature
Aging (with time)
Capacitance Stability
Aluminum
Polymer
© 2019 KEMET Corporation
Ta Polymer
(Solid)
Al Electrolytic
(Wet)
Supercapacitor
(Wet)
X5R/X7R Ceramic
(Solid)
Operational Life
Operating
Temperature Range-55°C to 105°C -55°C to 125°C -55°C to 105°C -40°C to 85°C
-55°C to 85°C (X5R)
-55°C to 125°C (X7R)
Mounting Pb-free Reflow Pb-free Reflow Pb-free ReflowHand-iron or Auto-iron
MountingPb-free Reflow
Reliability
Aluminum
Polymer
© 2019 KEMET Corporation
Ta Polymer
(Solid)
Al Electrolytic
(Wet)
Supercapacitor
(Wet)
X5R/X7R
Ceramic (Solid)
Energy Per Device
(up to) - mJ40 200 650 2
Energy Density
(up to) - mJ/cm3 320 180 3100 95
where: E = Energy, Joule
C = Capacitance, Farad
Va = Application Voltage, Volt
Vd = Drop-out Voltage, 2.5 Volt
Available Energy Upon Applied Voltage
Aluminum
Polymer
© 2019 KEMET Corporation
Circuit Needs
High Energy
Density
Low Profile
Long Life
at 85°C
Parameter
Ta Polymer Al Electrolytic Al Polymer
Super-
capacitor Ceramic
Energy/cm3
Higher
Voltage
Height *
Capacitance
Stability
Reliability
Why is Ta Polymer Cap an Ideal Solution?
*On going project to get to low profile with Al Polymer
© 2019 KEMET Corporation
Capacitor Type Series Data Sheets
Ta Polymer
(Solid)
T520 / T521 / T523 /
T545 / T548
www.kemet.com/Lists/ProductCatalog/Attachments/651/KEM_T2079_SSD.pdf
Al Electrolytic
(Wet)
EXV Series
EDT Series
www.kemet.com/Lists/ProductCatalog/Attachments/287/KEM_A4003_EXV.pdf
www.kemet.com/Lists/ProductCatalog/Attachments/653/KEM_A4054_EDT.pdf
Aluminum
Polymer
A765 Series
A767 Series
www.kemet.com/Lists/ProductCatalog/Attachments/648/KEM_A4070_A765.pdf
www.kemet.com/Lists/ProductCatalog/Attachments/649/KEM_A4071_A767.pdf
X5R/X7R
Ceramic (Solid)
X5R Commercial
X7R Commercial
www.kemet.com/Lists/ProductCatalog/Attachments/19/KEM_C1006_X5R_SMD.pdf
www.kemet.com/Lists/ProductCatalog/Attachments/53/KEM_C1002_X7R_SMD.pdf
How Can KEMET Help?
© 2019 KEMET Corporationwww.engineeringcenter.com
How Can KEMET Help?
© 2019 KEMET Corporation
Three Key Elements
1. Height
2. Energy
• Output Power (Watts)
• Hold-up time (milliseconds)
• Application Voltage (Volt)
• Drop-out Voltage (Volt)
3. Board Space
T545 Energy Calculator
ec.kemet.com/tools
How Can KEMET Help?
© 2019 KEMET Corporation
Energy Calculator
23
© 2019 KEMET Corporation
Thank You!