Qualcomm updates RF360 to support X16 GbLTE modems

New RF front-ends from top to bottom, premium to emerging markets

Qualcomm Snapdragon logoToday’s blizzard of Qualcomm news brings us to the RF side with a new RF360 suite. If RF front-end solutions and PA news is your thing, SemiAccurate has the story for you.

As you are probably aware the RF front-end category has four main components, envelope trackers, antenna tuners, antenna switches, and PAs. Much of this looks like a black art to the normal CPU and GPU focused enthusiasts, but it is a very necessary component set. The RF360 line may not have the same appeal as a new SoC but if you like you data stream to work and your calls not to drop, things like the RF360 are deadly important.

The biggest news is the new QET4100 which as the name doesn’t really suggest is the worlds first 40MHz envelope tracker. As you might have guessed this is quite important for things like the new X16 GbLTE modem which needs 40MHz bandwidth chunks to do its job. Not coincidentally the QET4100 is designed to work with said modem so no iPhone 4 problems for the Snapdragon 820 designs are forecast.

The next step in the RF front-end world is the PAs and switches needed to support 40MHz in the new high bands that are fast becoming available. Having a nicely tracked envelope is fine and dandy but if you can’t send power to it, or switch the bands appropriately, it is not very useful in the real world. To fix that there is the Qualcomm QPA4340 which works with the QET4100 and X16. It is a PA and antenna switch designed for 40MHz slices and the new high bands. Again with the coincidence, almost eerie.

As you might expect things that use the X16 modem tend to be in the highest tier of devices, nice for margins but the volumes can be a tad limited. If you want these features in the meat of the market, say for the Snapdragon 400 and 600 SoCs, you need different RF360 products. Those would be the QAT2514 and QAT2522.

The QAT2514 is a SP4T aperture tuner which brings antenna tuning to the mid-tier SoCs and their attendant radios. It works with the QAT2522 antenna switch for antenna diversity on the same platforms. This pairing supports closed loop tuning, open loop tuning, aperture switching, antenna diversity, and hybrid modes. Basically you can have all the goodness previously found in the 800-series SoCs/modems in the lower tiers, and all at a price point that was previously unattainable.

At the really low-end of the market, either by SoC line or price, a lot of advanced RF front-end features are just not economically viable. For those designs Qualcomm has two new RF360 components, the QPA4373 and QPA4351, both are PAs. The key feature here is they are PCB compatible and have PoP and de-PoP options as well. They currently support 600-series to 200-series Snapdragon SoCs, basically those designs aimed at emerging markets.

In the end the new RF360 suites raise the bar on the high-end for X16 modems and Snapdragon 820 designs with 40MHz antenna tuning and related parts. The mid-tier SoCs get the features that were exclusive to the high-end a generation or two ago, and do so at a reasonable price. The low-end gets better PAs which seems a bit anticlimactic until you realize the lowly Snapdragon 212 now can come with an X5 LTE modem. Rock-bottom price points and Cat 5 LTE, not a bad place to start and it goes up from there.S|A

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Charlie Demerjian

Roving engine of chaos and snide remarks at SemiAccurate
Charlie Demerjian is the founder of Stone Arch Networking Services and SemiAccurate.com. SemiAccurate.com is a technology news site; addressing hardware design, software selection, customization, securing and maintenance, with over one million views per month. He is a technologist and analyst specializing in semiconductors, system and network architecture. As head writer of SemiAccurate.com, he regularly advises writers, analysts, and industry executives on technical matters and long lead industry trends. Charlie is also a council member with Gerson Lehman Group. FullyAccurate