hf/rf ZONE Products for the week of January 26, 2004
Agilent Technologies Says . . .
ACMD-7401 ACPF-7002: Next-Gen. FBAR Duplexer And Full-Band
Transmit Filter
Latest Devices Deliver Same Proven Performance in 66 Percent
Smaller Packages
Agilent Technologies Inc. announced the industry's smallest film bulk acoustic resonator (FBAR) duplexer for handsets, data cards and other wireless products operating in the U.S. PCS (personal communications service) frequency band. The ACMD-7401 FBAR duplexer is 66 percent smaller than Agilent's first-generation HPMD-7904 FBAR duplexer, which is currently shipping in more than 80 percent of new handsets designed for the U.S. PCS market.
Duplexers permit simultaneous two-way voice or data transmission in wireless products by separating incoming from outgoing communications. The ACMD-7401 is the first duplexer built with Agilent's innovative Microcap bonded-wafer chip scale packaging technology. This process allows the ultrasmall filters to be assembled in a molded-chip-on-board (MCOB) module that is less than 1.4 mm high with a 5 mm x 5 mm footprint, less than one-tenth the volume of competing ceramic devices. This ultrathin package makes it possible to design even slimmer handheld phones, and the tiny footprint allows for additional handset features such as a camera module. These dimensions also enable miniature RF modules with increased functionality to be embedded into other portable consumer appliances. Agilent also today introduced a new, smaller FBAR full-band transmit filter (ACPF-7002) that incorporates Microcap technology.
"The FBAR's size and performance advantage has already resulted
in more than 20 million units shipped, and our new, smaller duplexer builds
on the success of our first-generation product," said Bryan Ingram,
vice president and general manager of Agilent's Wireless Semiconductor Division.
"Unlike some competing small package size devices, Agilent's new FBAR
products offer the same high performance specifications as our previous
family."
analogZONE Says . . .
When I reviewed the original ACPF-7001 FBAR transmit filter in May 2002 (it later won an analogZONE Product of the Year Award for 2002) I said about it:
"The costs of this solution are going to be 20-25% better in volume than that using SAW filters, the real estate taken up is going to be about 80% less, the performance is better, the profile is lower, and the receive side performance is improved by default -- what's not to like? The ACPF-7001 has winner all over it and you should expect to see almost universal adoption in PCS-band handsets. No doubt there are other duplexers/filters in the offing and we should certainly expect to see a duplexer combined with a power module in the near future. The other, unspoken, destiny of this technology is, of course, in oscillators and it will be interesting to see where Agilent goes with that aspect of things."
Well I sure called that one -- except for combining with a power module, yet, and the elusive oscillator functionality is getting closer. Agilent now reports that the filter and the subsequent duplexer have been designed into nine of the top ten CDMA PCS-band handsets in the US, with more than 2 million FBAR duplexers shipping a month. The strength of the sales and design wins says that the technology (for which there is a reasonable explanation of how it works in the original review) has been accepted as mainstream, and as Agilent has met its obligations to vendors the technology is also trusted. It is rugged and can take power that a SAW product can not. Also, filter, duplexer and E-pHEMT PA all from the same source is a tantalizing solution for handset manufacturers.
The newest twist with these next-generation duplexer and transmit filter is size and another technology breakthrough. Agilent is calling it Microcap packaging. The FBAR wafer (the full thing, not just a cut die from it) is bonded with a "cap" wafer, also in CMOS, which can be used as a lead out in the individual, sealed filters, also offers tantalizing possible uses at a later stage: Certainly passives of L, C and R could be processed-in which immediately suggests stubs and other matching techniques, as well as an active oscillator? Down the road there is the possibility of other active circuits. Agilent believes the costs of the additional wafer are a wash because of the elimination of the original ceramic package. Instead the filters are assembled on PCBs and wirebonded (could also be flip chips) with an overmolding. The reason for the PCB is to spread the connections to an industry-usable spacing. Even so, the size of the new filter and duplexer are dramatically smaller than the originals -- and, perhaps even more important, they are thinner at 1 mm and 1.4 mm respectively.
There seems to been no compromise in the performance of the new parts. The duplexer, for example, offers a typical 1.8 dB insertion loss (54 dB interferer blocking) in the PCS transmit band of 1850 MHz to 1910 MHz, and a blocking of typically 44 dB in the PCS receive band of 1930 MHz to 1990 MHz with an insertion loss of 2.2 dB typical. The full-band transmit filter offers a typical 2.5-dB insertion loss over the transmit passband, while providing a minimum of 33-dB attenuation over the receive band to improve the noise floor, and therefore sensitivity, of the receive channel.
Return losses in both products are of the order of 10 dB over the relevant frequencies.
Agilent has now proven the technology that was 7 years in R&D, and has proven that it can deliver parts of the quantity, quality and ruggedness that the industry demands. It is now in a position to develop the uses of the Microcap technology, to move to lower frequencies and to finally be in a position to boot SAW filters out of the last bastion they have in GSM handsets. And I believe that finally this year we will see FBAR/PA modules, but maybe not from Agilent itself…
Both the ACMD-7401 duplexer and ACPF-7002 filter are sampling with production quantities available to some vendors before the end of January 2004. The ACMD-7401 is priced at $2.45 and the ACPF-7002 at $0.54, both in 100-k piece lots.
Data
Sheet (ACMD-7401)
Data
Sheet (ACPF-7002)