Will the Real SiP Please Stand Up?
Incisor Issue 103, January 2007 - Today, the increasingly connected consumer is perfectly within his or her rights to expect that mobile devices such as cellphones and laptop computers will support up to 5 wireless technologies, including WLAN, Bluetooth, GPS, WiMAX and GSM or CDMA – all of them together, or in various combinations. That is five technologies today, and there is no real indication where this might stop. Soon Wibree, NFC, RFID and even ZigBee may need to be considered.
Not only do these wireless technologies all need to be integrated, but they all have to work together happily, and their integration needs to have little impact on the cost and power consumption of the device. A tall order, without doubt.
This is setting device manufacturers an enormous problem, as such levels of connectivity are not easily integrated. The most logical solution is a single, multi-function System-on-Chip (SoC) silicon product from one vendor. Wi2Wi, a specialist in multi-function integrated wireless solutions, suggests that there is another, and often more efficient solution. Wi2Wi designs System-in-Package (SiP) products that completely integrate multi-function wireless systems, and feature patent-pending hardware and software design techniques for co-existence, heat dissipation, yield improvement and power reduction.
SoC or SiP?
Before getting into the detail of why SiP is good, Wi2Wi founder, President and CEO Ramzi Alharayeri pointed out the conundrum hinted at in the title to this article, and was keen to stamp on a myth circulating the wireless industry. “A SoC is never a one-chip solution. All SoCs need some external components, so a SiP can be considered a SoC plus its external components. There is a belief that SoC and SiP are competing against each other, but this is just not true. In reality, they are not so different and are actually complementary. It is even true to say that SiP is needed to bring SoCs to market.”
Having de-bunked the SoC versus SiP myth, Alharayeri outlined the key characteristics and benefits of the SiP. “At the base level, a SiP is a combination of dies, packaged parts, and passive components inside a single package similar in size to the ceramic products. Crucially, we are in the position today that Known Good Dies (KGDs) are now available for memories, processors and other critical components needed for wireless systems. Our SiP solutions integrate 70-80 components, including the RF solutions from our partners, on a BT-Resin substrate, which is the equivalent of a PCB. SiP has become a reality due to the advancements in substrate, assembly and test technologies in addition to the availability of KGDs. “
Best of breed combinations
Wi2Wi combines its SiP skills with the wireless systems expertise of partners such as Marvell, CSR, SiRF and Atheros Communications. This means that Wi2Wi is creating and delivering much needed, integrated wireless systems in partnership with industry leaders. “A customer may well have already identified these semiconductor companies as the source of the industry’s leading WLAN, Bluetooth or GPS solutions, and Wi2Wi can provide optimized combinations of the respective best of breed products” commented Alharayeri. In other words, the customer is no longer tied-in to one vendor for different technologies, as would be the case with a SoC. If vendor ‘a’ has the best Bluetooth technology, vendor ‘b’ the best WLAN technology, and vendor ‘c’ the best GPS technology, there is no reason why they cannot be combined in one SiP.
Key benefits of the SiP are therefore the very small form factor, leading edge performance combined with low power consumption, very fast to time to market – no more than 6 months thanks to leveraging off-the-shelf components - and lower system design, test and implementation costs. Dhiraj Sogani, Wi2Wi’s General Manager & Senior Vice President, Advanced Technology, explained that the SiP will also offer better and more reliable electrical performance than a PCB – and in this way is comparable to LTCC - and is a more flexible system than SoC. “It can be re-configured for different applications (different memory, etc.) and it is easy to add functionality, whereas a SoC cannot be modified. As if this was not enough of a challenge, the continual advancement of technology specifications - Bluetooth, for example, has progressed through version 1.0, 2.0 and now version 3.0 is being drafted, and WLAN, which is available in 802.11b,g,a and n variants – means it is even harder for SoC developers to offer ‘just in time’ availability.”
The time to market factor
All of this means a re-think is necessary over what appeared to be a clear cut decision between two alternatives. Device manufacturers believe the choice is to use SoC or SiP solutions to wirelessly enable their products. And urban legend has it that SoC is better, combining as much as possible within one piece of silicon – e.g. Wi-Fi and Bluetooth, This must bring cost, size and power consumption benefits, surely? There is some true in this, according to Sogani. However, the time to market for a SoC is very lengthy. “It will take even the biggest semiconductor company between 18 months and 5 years to complete a SoC that combines even just two technologies such as Bluetooth and Wi-Fi on a single, multi-function chip. This is because the task is very complex with many problems along the way. This, in turn, means that the cost of development, including tooling and testing, is huge – typically $25 – 30 million.” Sogani cited the example of one of the most dynamic semiconductor companies, which, despite its expertise, has taken 2 years to get from the point that it announced a Wi-Fi SoC, to that product being market ready. When the SoC arrives, it may well be able to offer a smaller form factor, lower cost and lower power consumption, but in a super-competitive market, who can afford to wait that long?”
This creates a real opportunity for Wi2Wi, as device manufacturers need multi-function wireless solutions today, not in months or years time. However, it is not just a case of throwing RF chips and assorted components onto a substrate. Wi2Wi has a highly-experienced engineering team with considerable skills in packaging, RF and system optimization and coexistence algorithms. This has enabled the company to quickly establish itself as a SiP expert. The engineering team’s skills are in constant demand, as there are plenty of integration challenges. Signal integrity is very important, for example, so the RF section has to be properly isolated, the wireless technologies have to co-exist without interfering with each other, and power supplies have to be isolated in order to avoid noise problems.
Testing is always a challenge for integrated silicon products, but Sogani was able to reveal a recent, beneficial development. “We are now able to carry out RF testing at wafer and die level, which has been a big issue historically. Good wafer and die-level testing brings SiP in line with SoC, and is therefore an important advance. Having said that, SoC’s are becoming more and more complex, and so this will continue to have an impact on testing for SoC developers.”
While developing bespoke SiP designs for its customers, Wi2Wi’s is building a portfolio of off-the-shelf products. These include:
• The W2CBW003, which combines CSR’s BC04-ROM Bluetooth and Marvell’s 88W8686 802.11b/g Wi-Fi products in a 12mm x 12mm x 1.4mm package. Sample quantities and development kits are available now, while production quantities will be available in Q1 2007.
• The W2CBWG01 is an integrated Bluetooth, WLAN and GPS solution that offers completely tested coexistence of 3 radios. It is on a Half Mini PCI card form factor and is aimed at the mobile PC market.
• Wi2Wi has also used its integration skills to create the W2SG0001 module. This is a completely integrated GPS system based around SiRF technology, and offers ultra low power consumption in a 15mm x 15mm x 2.5mm form-factor. It is available now in production quantities and in development kits.
• Staying with SiRF’s GPS technology, Wi2Wi has also created the W2SG0004 module that is a completely integrated GPS system on a 20 Pin PLGA package of 11.2mm x 12mm x 2.5mm dimensions. This is also available now.
The availability of Wi2Wi’s growing range of multi-function wireless SiPs means that there is hope for electronics companies building products that need to be wirelessly connected, such as cellphones, portable computers, PDAs, digital cameras and camcorders. Multiple wireless technologies from the industry’s leading semiconductor companies can be integrated now – when the consumer wants to buy them – rather than at some point in the future.
At the beginning of this article, we asked “will the real SIP please stand up?”, as levels of awareness were low, and some believed that there was a SiP / SoC debate and a need to align with one or the other technology. It is now clear that SoC and SiP are not competing. SoC products can deliver highly integrated, very efficient solutions, but while the complex development of a SoC rolls along, SiP solutions from Wi2Wi offer substantially faster time to market, lower cost, higher reliability and higher flexibility.
There is no substitute for having a good product, at a good price, that people can buy today.
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