Opportunities andChallenges for SmarterMobile DevicesNamsung (Stephen) Woo

Samsung Electronics

h FIRST OF ALL, I would like to congratulate all

EDA professionals for the 50th anniversary of the

Design Automation Conference (DAC). Since the

beginning of DAC, both semiconductor industry and

EDA industry have grown a lot. If we consider the

revenue of last twenty years (1993–

2012) alone, the semiconductor indus-

try has grown 3.8 times (from $66B to

$251B) and the EDA industry 5.2 times

(from $1.3B to $6.7B).

Looking back the papers presented

at DAC, we can easily find that DAC has

been leading and supporting the de-

sign and manufacturing of semicon-

ductor solution. In 1980’s, the areas of physical

design, circuit simulation and testing saw many

papers. In 2000’s, papers in the areas of low power

design, verification and embedded systems led DAC.

In the last several years, we found strong interest in

the areas of thermal issues (for highly integrated

chips) and variation tolerance (for advanced sili-

con manufacturing). Interestingly, these two areas

Editor’s notes:This article is based on a keynote address presented by the author at the50th DAC. It discusses the state-of-the-art in semiconductor technology andits interaction with smart mobile devices, wide I/O memory access andflexible displays.

VYervant Zorian, Synopsys

Namsung (Stephen) Woo gives his keynote address.

IEEE Design & Test2168-2356/14 B 2014 IEEE Copublished by the IEEE CEDA, IEEE CASS, IEEE SSCS, and TTTC56

50 Years of DAC: What Lies Ahead

Digital Object Identifier 10.1109/MDAT.2014.2315955

Date of current version: 19 May 2014.

address key technical challenges of semiconductor

solutions for smart mobile devices.

This article will first examine recent trends of

smart mobile devices and their influence on semi-

conductor industry. Then, we will describe several

new aspects of smarter devices (i.e., future wave of

smart devices) and their impact on semiconductor

and EDA technology.

Mobile devices andsemiconductor industry

The driving force of the semiconductor industry

has recently changed from PC to mobile device. For

instance, the number of smart phones sold globally

in 2013 is expected to be 930 million units, and the

number will grow to 1.1 billion units in 2014. Tablets

are also growing fast: from 210 million units in 2013

to 290 million units in 2014.

Along with the volume increase, smart devices

have seen enhanced computing power for complex

applications. The mobile application processor

(AP), which runs application software of smart de-

vices, contains CPU core(s), graphics core(s), multi-

media core(s) and other IP blocks in one silicon die.

Since mobile devices are running on battery, mobile

AP has to consume low energy including low stand-

by current. As a result, mobile AP is typically built on

a low-power (and, as a result, low-speed) silicon

process.

Then, how can we get higher performance of

mobile AP while consuming low energy? This diffi-

cult goal has been achieved mostly by three areas of

development: advanced CPU/SOC architecture, so-

phisticated circuit design (with the help of EDA

technology) and advanced silicon process.

Figure 1 shows a brief history of mobile AP for

smart phones. The X-axis is the year in which a

mobile AP was put in production, while the Y-axis

shows the performance in terms of DMIPS (Dhrys-

tone Million Instructions per Second). In 2009, for

the first time in mobile AP history, a mobile AP

recorded 1.0 GHz clock speedwith low-power 45 nm

silicon process. In 2010 and 2011, mobile AP with

dual CPU cores and quad CPU cores appeared, re-

spectively. In 2012/13, mobile APs with eight CPU

cores, four big cores and four little cores, were de-

veloped and used in smart phones [1]. As shown in

the figure, the computing performance measured in

DMIPS has been increasing every year.

In order to offer high computing power at low

energy consumption, many design techniques have

been developed, and DVFS (Dynamic Voltage and

Frequency Scaling) is one of them. Its goal is to

adjust mobile AP’s supply voltage (Vdd) according

Figure 1. Progress of mobile AP since 2008.

March/April 2014 57

to its workload. Figure 2 shows an operation

example of DVFS, in which high Vdd is used when

AP deals with heavy workload and low Vdd when

workload is light. In reality, AP’s firmware controls a

PMIC (power management integrated circuit) that

provides Vdd to AP.

Silicon process plays an important role to

support mobile AP. Figure 3 shows the progress of

CMOS process technology for mobile applications

during 2000–2013. The poly-SiOn technology has

been used for the 45 nm process, and since then,

high-K/metal-gate (HK/MG) technology has been

adopted since 32/28 nm process. For 14 nm process

(in some cases, 16 nm process), a 3D transistor,

called FinFET, is being used.

Other areas which have experienced dramatic

growth in smart devices include camera sensors and

display driver chips. For instance, in the CMOS-

based camera sensor chips for smart phones, the

number of pixels in one sensor chip grew from

1.3M pixels (in 2005) to 13M pixels (in 2012), while

the size of camera sensor chip remains basically

the same.

Smarter devices: The next wave ofsmart mobile devices

The next wave of smart mobile devices, ‘‘smarter’’

devices, will offer much better user experience (e.g.,

gesture recognition) and much broader solutions

Figure 3. Progress of CMOS Process Technology.

Figure 2. DVFS operation.

IEEE Design & Test58

50 Years of DAC: What Lies Ahead

(e.g., context-sensitive comput-

ing). In this article, however, we

will look at only two areas

related to technology.

Wide IO for higher bandwidthbetween AP and memory

Three elements of smarter

devices drive up the bandwidth

requirement between mobile

AP and memory: 1) higher

data rate of air interface (e.g.,

LTE-A), 2) higher graphics per-

formance, and 3) higher display

resolution (e.g., UHD). The

‘‘Wide IO’’ technology, in which Memory is

connected to AP by TSV (Through Silicon Via), is

the best known approach for high bandwidth

between AP and Memory.

Figure 4 shows TSV in Wide IO and a way of

putting memory die on AP die. In addition to high

bandwidth, the Wide IO technology provides low-

energy memory access because of the closeness of

memory to AP.

The Wide IO technology has recently been real-

ized in industry. The ‘‘V’’ system, which offers 512

data lines between AP and mobile DRAM via TSV, is

now running real applications [2]. Experimental

data show that the current implementation of Wide

IO offers 14% higher bandwidth than LPDDR3 and

consumes 60% less energy than LPDDR3.

One challenge of the Wide IO technology is

complex memory architecture. That is, the mobile

AP has to deal with two types of memory (i.e., inter-

nal memory connected by TSV and external mem-

ory) with different access time. Mobile software has

to be intelligent if it wants to utilize internal memory

as much as possible. Some research groups have

made good progress in managing this complex

memory system in smarter devices.

Flexible displayThe display resolution of smart mobile devices

has been moving up, and current smart phones offer

full HD (FHD) resolution. In the near future, UHD

display will be used in high-end smarter devices.

One disruptive display technology for smarter

devices is ‘‘flexible’’ display. As demonstrated at this

year’s (2013) CES show [3], flexible display is

working well at laboratories. Recently, in 3Q13, an

early form of flexible display, called ‘‘curved’’display,

was adopted in two smart phone models from two

companies. It is reasonable to expect smarter

devices with ‘‘fully’’ flexible display in the next

couple of years.

If we have fully flexible display at smarter

devices, the other electronics part (i.e., a PCB with

multiple chips on it) of smart devices must also

change. That is, if the current form of PCB does not

change, the advantages of flexible display will not

be fully exploited.

For the future path of electronics portion in

smarter devices with flexible display, we can learn

lessons from the current display driver IC. As shown

in Figure 5, the current display driver IC’s are put on

a plastic film, which is connected to a display.

If we can reduce the total number of chips in

smarter devices from more than dozen (which is the

case with the current smart devices) to one or two,

Figure 5. Display driver IC on a plastic connectedto a display.

Figure 4. Wide IO technology.

March/April 2014 59

and if we can put them on a plastic film, we would

be able to build smarter devices that fully utilize

flexible display. If we get this solution, we will have

SOP (System on Plastic) or SOF (System on Film)

that works naturally with flexible display.

SMART MOBILE DEVICES have contributed to the

growth of semiconductor industry, and the trend will

continue in the near future. In this article, we de-

scribed an interaction between smart mobile de-

vices and semiconductor solution; we showed that

high-performance and low-energy mobile AP’s

allowed smart phones to progress, and vice versa.

We also touched smarter devices (i.e., the next

wave of smart mobile devices) and two technical

initiatives, wide IO and flexible display, for them. For

each initiative, we introduced the most recent

result(s) and discussed future paths.

EDA technology has been helping semiconduc-

tor industry (both in design and manufacturing)

which, in turn, contributed to smart devices. We

hope this virtuous circle continue in the future. h

h References[1] AP Data Book, System LSI, Samsung Semiconductor,

2010–2013.

[2] ‘‘V’’ System With Wide IO Solution, System LSI,

Samsung Semiconductor, 2013.

[3] Keynote Talk by This Author at CES 2013, Las Vegas,

NV, USA, Jan. 2013.

Namsung (Stephen) Woo is the president ofSystem LSI at Samsung Electronics, San Diego, CA,USA. Before joining Samsung, he worked at BellLaboratories, Murray Hill, NJ, USA and TexasInstruments, San Diego, CA, USA.

h Direct questions and comments about this articleto Namsung (Stephen) Woo, System LSI, SamsungElectronics.

IEEE Design & Test60

50 Years of DAC: What Lies Ahead