LPDDR3 and LPDDR4: How Low-Power DRAM Can Be Used in High-Bandwidth Applicationsin High-Bandwidth Applications

Mobile Forum 2013

Marc Greenberg

Director, Product Marketing

Synopsys

Copyright © 2013 Synopsys

AgendaAgenda

• High-Bandwidth, Low-Power DRAM Today

• Using “Dual Personality” Memories Effectively to Reduce Power Consumption

• System Environment Around LPDDR Devices

• Future Direction

High Bandwidth TodayHigh Bandwidth Today

• Shipping Application Processors

– Up to 4 channel LPDDR2

– 2 channel LPDDR3-1600

• LPDDR3 in mass production per • LPDDR3 in mass production per manufacturer websites

– One and two channel LPDDR3-1600 up to 4 die package with 4Gbit density

• Early access status for LPDDR3-2133 speedsSources: http://www.samsung.com/us/business/oem-solutions/pdfs/PSG_2H_2012.pdfhttp://www.hynix.com/inc/pdfDownload.jsp?path=/datasheet/Databook/Databook_1Q'2013_MobileMemory.pdfhttp://www.samsung.com/global/business/semiconductor/minisite/Exynos/news_19.html

20

30

40

50

60

70 Today’s requirements

Today’s low-powerDRAM devices

GByte/secpeak bandwidth

Potential future low-powerDRAM devices

How Potential Future Devices CompareHow Potential Future Devices Compare

0

10

* No published JEDEC standard exists. Standard publication is dependent on JEDEC process. Specification or performance is subject to change without notice. Part availability dependent on manufacturer.

*

HighHigh--Bandwidth Interface ExamplesBandwidth Interface Examples

• PCI Express Gen3

– 1GB/s (8Gb/s)

• USB3.0

– 0.625GB/s (5Gb/s)

• HDMI 1.4 (4k)

– 1GB/s (8Gb/s)

• LPDDR4

– 4.2Gb/s parallel

– No embedded clock

– 14GB/s/channel

LP DRAM Bandwidth DriversLP DRAM Bandwidth Drivers

LPDDR4

What is Low Power?What is Low Power?

• Laptop with a 90 Watt-hour battery?

• Tablet with a 40 Watt-hour battery?

• Phone with a 5-10 Watt-hour battery?• Phone with a 5-10 Watt-hour battery?

Reducing Power in DRAMReducing Power in DRAM

• DRAM core power usage

– Generally a function of device organization, usage, manufacturing technology

• Standby power• Standby power

– Available features for controlling power

• IO signaling power

– Function of voltage swing, termination, IO capacitance, frequency, load, …

• Power dependent on energy per bit (TBD) and system configuration

Let’s Call Let’s Call IIt “Less Power”t “Less Power”

• 3mW/Gbps (3pJ/bit) is a great figure of merit but…

Energy per Bit

(pJ/bit =

mW/Gbit/sec)

2-channel

LPDDR4

3200

2-channel

LPDDR4

4266

4-channel

LPDDR4

3200

4-Channel

LPDDR4

4266

Not including: Memory core power, address/control bus, PHY power,

memory controller power… or any computation that the target system

might be doing… operating the display… accessing the net… etc.

merit but…mW/Gbit/sec) 3200 4266 3200 4266

1 205mW 273mW 410mW 546mW

2 410mW 546mW 819mW 1.09W

5 1.02W 1.37W 2.05W 2.73W

10 2.05W 2.73W 4.10W 5.46W

Low Power Low Power MMeets High Bandwidtheets High Bandwidth

• “Multiple personality” devices

– Low power, low bandwidth mode

– Extensive standby modes

– Infrequent full bandwidth usage– Infrequent full bandwidth usage

Normal OperationNormal Operation

• Low-speed operation

–< DDR1600, unterminated

–Using all LPDDR power reduction –Using all LPDDR power reduction capabilities when idle

When Can You When Can You GGo o FFull ull SSpeed?peed?

• When plugged in

• During time-bound occasional operations operations

–Boot

–Program launch

– Image/video processing

• Intermittently…

Requirements to run full speedRequirements to run full speed

• Available power

• Sufficient cooling

• Fully Trained interface• Fully Trained interface

• On-Die Termination

• Temperature Monitoring

• Memory controller and PHY in high-speed mode

Termination Termination -- HighHigh--Speed ModeSpeed Mode

510ps620ps 320ps

• 28nm silicon results

– Data eye measured at Write ball

– Wirebond package

– Worst case SSO

LPDDR2-1066

UnterminatedDDR3-1600

Terminated

LPDDR3-1600

Unterminated

Source: Synopsys

Finding the Ideal PCB EnvironmentFinding the Ideal PCB Environment

• PoP provides very short electrical connection forconnection forhigh speed andlow power

– But power dissipation limited

Finding the Ideal PCB EnvironmentFinding the Ideal PCB Environment

• Another option: Clamshell

–Used in Synopsys characterization

–Seen in at least one tablet–Seen in at least one tablet

Top side Bottom side

PCB

Application Processor

DRAM

Schematic side view

Memory Partitioning ConceptMemory Partitioning Concept

Channel 1 Rank 0

High Resolution

Video Processing,

Image Processing,

etc

Channel 0 Rank 0

Modem, OS

Kernel, Running

apps

Maximum

bandwidth

All chips active

Channel 1 Rank 1

High Resolution Video

Processing, Image

Processing, etc

Channel 0 Rank 1

Stalled/Sleeping Apps

Channel 0 Channel 1Application

Processor

Memory Partitioning ConceptMemory Partitioning Concept

Channel 1 Rank 0

High Resolution

Video Processing,

Image Processing,

etc

Channel 0 Rank 0

Modem, OS

Kernel, Running

apps

No video

Running apps

Ch0 active

Channel 1 Rank 1

High Resolution Video

Processing, Image

Processing, etc

Channel 0 Rank 1

Stalled/Sleeping Apps

Channel 0 Channel 1Application

Processor

Memory Partitioning ConceptMemory Partitioning Concept

Channel 0 Rank 0

Modem, OS

Kernel, Running

apps

No video

Low activity

Ch0 R1 active

Channel 1 Rank 0

High Resolution

Video Processing,

Image Processing,

etc

Channel 0 Rank 1

Stalled/Sleeping Apps

Channel 1Application

ProcessorChannel 0

Channel 1 Rank 1

High Resolution Video

Processing, Image

Processing, etc

Memory Partitioning ConceptMemory Partitioning Concept

Channel 0 Rank 0

Modem, OS

Kernel, Running

apps

Basic “keep

alive” AOACLow frequency

Ch0 R1 active

Channel 1 Rank 0

High Resolution

Video Processing,

Image Processing,

etc

Channel 0 Rank 1

Stalled/Sleeping Apps

Channel 0 Channel 1Application

Processor

Channel 1 Rank 1

High Resolution Video

Processing, Image

Processing, etc

Memory Partitioning ConceptMemory Partitioning Concept

Channel 0 Rank 0

Modem, OS

Kernel, Running

apps

Complete standby

Channel 1 Rank 0

High Resolution

Video Processing,

Image Processing,

etc

Channel 0

Channel 0 Rank 1

Stalled/Sleeping Apps

Channel 1

Channel 1 Rank 1

High Resolution Video

Processing, Image

Processing, etc

Application

Processor

Summary of LowSummary of Low--Power DRAM Power DRAM Interface TechniquesInterface Techniques

• Select a low-power DRAM

• Use DRAM low-power features

• Frequency scaling

– Switching termination on/off– Switching termination on/off

• DRAM clock gating

• Partitioning memory into DRAM

• On-chip power control for AP

– Clock gating, power gating (esp. DDR IOs), DVFS

– Etc…

20

30

40

50

60

70 Today’s requirements

Today’s low-powerDRAM devices

GByte/secpeak bandwidth

Potential future low-powerDRAM devices

How Potential Future Devices CompareHow Potential Future Devices Compare

0

10

* No published JEDEC standard exists. Standard publication is dependent on JEDEC process. Specification or performance is subject to change without notice. Part availability dependent on manufacturer.

*

ConclusionsConclusions

• Future DRAM bandwidth will continue to increase

• Power is reduced in LPDDR4, but still proportional to bandwidthproportional to bandwidth

• Use multiple techniques to meet performance and power goals of high-bandwidth low-power DRAM

Thank YouThank You

Marc Greenberg

Director, Product Marketing

Synopsys

Copyright © 2013 Synopsys

Mobile Forum 2013