TI: Mobile phones split architecture will rise
Greg Delagi, senior VP and general manager of Texas Instruments’ wireless terminals business unit believes that the so-called “split architecture” for handsets is set to rise.
The split refers to the digital processing that in some designs is split between a modem and an applications processor. In other designs, particular for simpler phones, attempts are made to address the user interface and application processing on an integrated base band chip.
However, with its development of the OMAP line of chips, which originally stood for open multimedia applications platform, TI has clearly backed the idea of sophisticated application processors that are kept separate from the heavy lifting for the cellular communications protocol.
Delagi conceives of a modern mobile phone as having four main building block ICs. One is the RF for the main call and a second is the RF for all the ancillary activities such as Bluetooth, FM radio, Wi-Fi and GPS. The third is the modem or radio base band chip operating in the digital domain. And last, but by no means least in Delagi’s view, is the application processor.
Of those four blocks Texas Instruments is emphasizing the application processor and the combination peripheral RF. “We still do some base band business but we are shifting our emphasis to OMAP and connectivity. That’s where the money is to be made,” Delagi told EE Times. “At the 2009 Mobile World Congress we announced OMAP 4. This year we’ve got silicon and a ton of applications.”
Delagi said that as multimedia demand explodes so the split architecture would prosper. “OMAP supports a split architecture, iPhone is a split architecture. Even the Nokia N900 is a split architecture. Remember at the same time as multimedia demand is increasing the modem has become much more complex.”
“What I see happening is that each of these blocks will evolve at their own pace.” He added: “The connectivity block is evolving in the same way so we have arrived at WiLink 7.0 which includes WiFi 802.11n, GPS, Bluetooth and FM. At the same time the main RF transceiver will evolve, but we are not involved in that. Our approach is agnostic.”
There is in the interesting distinction that TI is able to manufacture internally the WiLink combination chip but is increasingly outsourcing the leading edge digital CMOS used for OMAP chips.
The OMAP 4 is being introduced on a 45nm manufacturing process even as some OMAP 3 devices are being shrunk from 65- to 45nm. Delagi said that even though Texas Instruments was not investing in manufacturing plant for leading-edge digital it was helping multiple foundries develop process and remained committed to developing and selling digital chips.
He said that Texas Instruments would maintain multiple foundries as sources of manufacture and expected its large size to allow it command first call on foundries’ manufacturing capacity even in times of shortage.
In terms of design architecture some functions have to be left outside these main blocks—at least until they achieve such market penetration that it becomes more economic to include them than to have separate chip for those that require it. Delagi cited NFC as an important technology that has not yet hit the penetration to make it necessary to be integrated in a WiLink combination chip.
However, Delagi accepts that there is always pressure to integrate and that no chipset partition is set in stone. “As the pace of innovation starts to slow integration increases,” said Delagi.