Well, it only took two days for someone to burst Freescale's bubble about having an architecture under development that could jettison the front-end SAW filters for next-generation W-CDMA/GSM handsets.
Walking wearily down the aisle yesterday evening toward my last meeting of the day at 3GSM here in Barcelona, Doug Grant, ADI's director of marketing, pulled me aside and pointed out that the company's latest Othello-3 has already accomplished just that. And more.
Just to recap: It's imperative that designers find some way to get rid of bulky and costly SAW filters on the front end if they're to advance along the path toward higher integration of multiple radios. But doing so has been difficult due to the general inability to find an architecture capable of meeting the high-performance filtering SAW filters provide.
However, according to Grant, ADI has accomplished it by providing a certain level of pre-filtering in the LNAs followed by high-power mixers capable of handling the interferers. This is complimented by a transmit architecture that has reduced out-of-band emissions by up to 10 dB, thereby greatly reducing the possibility of bleed-through from the transmit channel to the receive channel. A paper on the latter was delivered this week at ISSCC in San Francisco.
Granted, Othello-3 is W-CDMA only, so it only caters to nine bands, versus Freescale's prediction of being able to do W-CDMA plus GSM's four bands, for a total of 13. However, according to Grant, work is underway to integrated GSM/EDGE with W-CDMA using a similar SAW-eliminating approach.
It's great to work in an industry where what you know one day is debunked the next.