Under the Hood: Evolution of the smart phone

Gregory A. Quirk and Jeff Brown, TechInsights
TechOnline

It is interesting to look at the different ways that HTC and Nokia, two companies that have very competitive and successful smart-phone offerings, arrived at their latest products. HTC used its background as a PDA manufacturer to create the TyTN 2, essentially incorporating phone functionality into a PDA. Nokia came into the smart-phone market from cell phones, so it needed to find ways to increase functionality without substantially increasing the size of its latest phone, the N95.

For a full archive of articles and related On-Demand seminars, click here Unlike the low-cost cell phone market, where products boast few bells and whistles beyond the ability to make and receive calls, smart phones are all about features. The HTC TyTN 2 and Nokia N95 are fairly comparable from a features standpoint. Both offer Bluetooth, HSDPA, Wi-Fi and GPS. HTC has an edge in terms of display size, battery and user interface, while Nokia offers a better weight, camera resolution and user storage capacity.

Both companies have succeeded in increasing functionality, but they have come about it from completely different directions. When HTC first began designing smart phones, its heritage in PDAs resulted in larger models, and required the company to look at ways to increase functionality and decrease the number of components in order to meet users' size and weight expectations. HTC has consistently reduced the number of packaged devices used, while increasing the number of dice per package. This enables a very efficient design with little duplication in on-chip functionality.

Nokia, meanwhile, has been increasing the number of chips per phone, delivering a very effective design. Nokia can leverage economies of scale, so that while the number of chips rises, the company is still able to reduce the bill-of-materials cost, engaging in a strategy of incrementalism to maintain common devices across many platforms and adding new functions through bolt-on features and devices.

One interesting aspect demonstrated by both companies has been an overall loyalty to chip vendors. For example, the three generations of HTC phones analyzed all had basebands from Qualcomm, Bluetooth support from Texas Instruments and NAND flash from Samsung. For Nokia, TI provided the applications processors and Samsung the memory. The only substantial company change came when TI got displaced by Cambridge Silicon Radio for the Bluetooth functionality, which is interesting given the strong relationship Nokia and TI have developed over the years, including creating devices together.

Not only have the phones evolved over time, but so have the chips. The flash memory used by HTC demonstrates this evolution. While the die size has remained relatively consistent, at about 140 mm², the density has increased considerably.

The Samsung memory used in the company's Universal product had a 256-Mbit capacity and was designed into a 160-nanometer process lithography for a 1.8-Mbit/mm2 rating. The TyTN used a 120-nm, 1-Gbit Samsung flash with a 7.6-Mbit/mm² rating. The latest HTC phone, the TyTN 2, again used Samsung memory, but this time it was created with a 90-nm process and offered a 2-Gbit capacity, resulting in a 14.2-Mbit/mm² rating.

This evolution is a stark example of how semiconductor manufacturers are helping advance capability without affecting form factor.

Another chip development over the years has come from Qualcomm. As that company has integrated more functionality into its baseband processors, more associated chips can be removed from the board, freeing up space, reducing the bill of materials and creating a more-efficient design. The Qualcomm MSM6250, used in the Universal, had limited functionality for supporting anything beyond the baseband features. To make up for this, HTC designed in the Intel (now Marvell) PXA270 for applications processing.

In the TyTN, Qualcomm's MSM6275 had more functionality, but there were also more requirements for multimedia applications, so two additional processors--the Samsung SC32442 and AMD Imageon 2282--were included. The result was a duplication of some functions, such as image processing, which all three components offered.

The new TyTN 2 uses the Qualcomm MSM7200, which is part of the company's convergence platform family. The device enables all of the functionality required without the need for any additional applications processors.

While HTC looked to Qualcomm for baseband and applications support, Nokia turned to TI. For the baseband, Nokia and TI worked together to develop Nokia-packaged, TI-die-marked solutions. For the applications processors, Nokia used the TI Omap family, migrating from the Omap1710 in the N90 to the Omap2420 in the N93 and new N95.

While both Omap devices were designed in a 90-nm process, the 2420 offered a significant functionality im- provement. Its ARM core was upgraded from an ARM9 to an ARM11, and power-management practices were put in place to shut down inactive sections of the die and conserve battery life.

Future smart phones must, of course, take cost and weight into consideration, despite bulking up on features. We expect much of the future market to be addressed by devices that weigh less than 150 grams, are less than 15 mm thick and bear a sub-$200 manufacturing cost.

Related links:
Under the Hood: Blackberry wins handset data-rate bakeoff
Design Focus: Optimize interprocessor communication in dual-baseband, dual-mode handsets
Tech Paper: Compelling graphics development for your mobile device

Gregory A. Quirk (gregoryq@semiconductor.com) is technical marketing manager at IC analysis company Semiconductor Insights, a CMP company.

Jeff Brown is a principal analyst at Portelligent, a CMP company. The group produces teardown reports and related industry research on wireless, mobile and personal electronics (www.teardown.com).