Electronic Design
Chipworks Analysis: Smartphone Teardown Reveals Integrated Radio Chip's Evolution

Chipworks Analysis: Smartphone Teardown Reveals Integrated Radio Chip's Evolution

One of the most hotly contested, though somewhat unheralded, components in leading smartphones and tablets is the integrated Wi-Fi SoC socket. It plays an integral role in these device’s bills of materials (BOMs), with estimated cost ranging between six and eight dollars. The socket is also a critical contributor to the consumer’s fun and functionality, since it handles 802.11 capabilities as well as integrates key spectrums such as FM and GPS.

The Wi-Fi SoC chip’s performance should not be taken for granted. Unlike the other silicon, where comparison of the number of megapixels and processor cores, clock speed, total RAM, and other features is straightforward, the Wi-Fi chip is a little harder to understand.  Moreover, when it doesn’t work well, the product’s functionality suffers greatly.

With this in mind, the question becomes “What is the state-of-the-art for these multiband radio chips?” Chipworks, a reverse-engineering (RE) firm that conducts tests and other various analyses to look for both IP infringement and technical innovation, investigated and compared several of the latest WiFi SoC devices.

In late 2010 and early 2011, the Broadcom BCM4329 single-chip 802.11n/Bluetooth/FM device (Fig. 1) was on fire, becoming the leading wireless socket in tablets, smartphones, and connected devices from manufacturers like Apple, Motorola, Samsung, and HTC. It was found in high-end consumer electronics devices such as the iPad, iPad 2, iPhone, XOOM, Galaxy S, Atrix, EVO 4G, and a seemingly endless list of consumer devices. In fact, over the span of a few months, Chipworks documented design wins for the Broadcom device in 18 unique teardowns of smartphones and tablets.

This device was truly a success story for Broadcom. It had become so popular that it was being dual-sourced from two foundries and pre-fabricated in modules from companies like Murata. In the fourth quarter of 2010, it’s estimated that this chip was incorporated into at least 50 million consumer devices—a very conservative number based on the shipment data of the top-selling mobile phones. 

The BCM4329 integrated a complete IEEE 802.11 a/b/g/n system (MAC/baseband/radio) with Bluetooth 2.1 + enhanced data rate (EDR), plus FM radio receiver and transmitter, all in a 6.49- by 5.54-mm (36.0 mm2) die. In addition, Broadcom claimed it was the “industry’s most integrated 65-nm single-chip combo device.”  By combining all of the key wireless features into one device, Broadcom helped companies reduce the BOM for electronics manufacturers.

It appeared that there was no end in sight for the BCM4329’s list of impressive design wins, until a teardown of the BlackBerry PlayBook in April 2011 revealed a new contender: Texas Instruments’ WiLink 7.0 (Fig. 2). As had been widely reported, TI was overwhelmingly the dominant device manufacturer in the PlayBook, scoring wins in eight out of the 20 devices we identified and catalogued. Although the PlayBook hasn’t yet become a resounding success, the device’s technical innovation makes it a real contender.

The WiLink 7.0, part number WL1283, was aimed squarely at displacing the BCM4329 and had some pretty compelling advantages. One particularly impressive feature was that, despite both the TI and Broadcom devices being manufactured at the same 65-nm process generation, the WiLink 7.0 measured 16% smaller than the BCM4329. Coming in at 5.35 by 5.65 mm (30.23 mm2), it allowed for more die per wafer, leading to a potential cost advantage.

The WiLink 7.0 also had features like Bluetooth 3.0, Bluetooth low energy (BLE) support, and GPS. It looked like this Texas Instruments device was well positioned to take a bite out of the BCM4329 market stranglehold.

However, Broadcom didn’t accept defeat upon the introduction of the WiLink 7.0. Before long, it scored a win for the Wi-Fi socket in the Samsung Galaxy II I9100.

When tearing down this smartphone, Chipworks was surprised to find Broadcom’s new BCM4330 802.11a/b/g/n MAC/baseband/radio with integrated Bluetooth 4.0+HS and FM transceiver (Fig. 3). This was an unexpected because the BCM4330 had only been announced in February 2011 at the Mobile World Congress in Barcelona, Spain. Typically, devices don’t start appearing in consumer products until 12 to 18 months after a public launch, suggesting that BCM4330 would not appear until the summer of 2012, rather than August 2011.

The Galaxy II was a big win for Broadcom. The smartphone became a popular flagship product for Samsung, and an expected hot seller. In fact, this development was particularly huge, since a basic design typically appears in several Samsung products concurrently.

More importantly, Broadcom had a proven design win with a chip that matched TI’s device in terms of features (with the exception of GPS), yet shrank the die to nearly 16% smaller than the WiLink 7.0, measuring 5.27 by 4.84 mm (25.51 mm2). Broadcom raised the bar by not only dropping the size, but perhaps the cost of the die, too. Still, the BCM4330 was lacking GPS, a cost that must be added elsewhere in the phone if it’s required.

After this new device introduction, it seemed that balance was restored in the Wi-Fi socket wars. However, a new competitor swiftly entered the scene, namely the MediaTek MT6620 Wi-Fi SoC (Fig. 4). In tearing down the Lenovo A60, a lower-end smartphone from China, we discovered the MediaTek device’s first proven design win. According to Digitimes, the A60—a full-featured smartphone at a very good price point ($160)—has been selling quite well. It’s probably one of the best we have seen from China Mobile to date.

The MT6620, housed in an AcSip Wi-Fi module (like the BCM inside Murata Wi-Fi modules), was announced in late July 2011. Like TI’s WiLink 7.0, the MT6620 integrates 802.11n Wi-Fi, Bluetooth 4.0+HS, GPS, and FM transmitter/receiver on a single chip. It’s also the exact same size at 30.2 mm\\[SUPERSCRIPT 2\\].

Based on what we know about the WiLink 7.0 and the BCM4330, the new MediaTek device is estimated to cost about $2.25 per tested die. Also, barring any licensing issues, the MT6620 should start appearing in smartphones and tablets in North America and Europe as well.

In the ongoing fight for leadership in the Wi-Fi SoC socket game, Chipworks has seen many new entrants and technological advances along the way. These manufacturers have made it an interesting race, continually one-upping each other at a pace that parallels the overall pace of innovation in connected devices.

In the end, it will be hard to pinpoint a definitive winner because the game is big, growing fast, and won’t stop anytime soon. Suffice to say, semiconductor companies are accelerating their R&D efforts in order to set new standards and bring the world more advanced, lower-cost consumer electronics products.

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