Solutions for Solid State Storage

1

Solutions for Solid State Storage

Applications

© 2019 KEMET Corporation

Cloud InfrastructureSolid State Drives


Market Driver


Common Terms or Expressions

• Power Loss Imminent

• Power Loss Protection

• Data-Loss Protection

• Data Persistence

• Hold-up

• Last Gasp


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


Product Category Requirements

Consumer(Tablets, Cameras, Mobile Devices)

Client(Netbook, Notebook, Ultrabook, Desktop)

Enterprise(HPC, Datacenter Server)

Data Loss Prevention Becomes More Critical


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


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)


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.


Data Flow Illustration

Transmit

Store

Write

• Host starts transmitting data

• Data stored in RAM buffer

• Data is saved in NAND


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.


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


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


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


Ta Polymer

(Solid)

Al Electrolytic

(Wet)

Supercapacitor

(Wet)

X5R/X7R Ceramic

(Solid)

Voltage

Temperature

Aging (with time)

Capacitance Stability

Aluminum

Polymer


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


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


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


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?

http://www.kemet.com/Lists/ProductCatalog/Attachments/287/KEM_A4003_EXV.pdf

http://www.kemet.com/Lists/ProductCatalog/Attachments/653/KEM_A4054_EDT.pdf

http://www.kemet.com/Lists/ProductCatalog/Attachments/648/KEM_A4070_A765.pdf

http://www.kemet.com/Lists/ProductCatalog/Attachments/649/KEM_A4071_A767.pdf

http://www.kemet.com/Lists/ProductCatalog/Attachments/53/KEM_C1002_X7R_SMD.pdf


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?


Energy Calculator

23


Thank You!

Solutions for Solid State Storage

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