- Samsung Galaxy Fold 5G is the world first mass-market 5G foldable smartphone shipping in the South Korean market
- Samsung selected Qualcomm’s proven first-generation Snapdragon 855 plus X50 5G modem chipsets to power the Galaxy Fold 5G
- Galaxy Fold 5G RF Front-End indicate support for three Sub 6GHz 5G frequency bands – up from a single band of earlier X50 designs.
- Design also hints to design provisions to support millimeter wave 5G capabilities in subsequent model SKUs of the Galaxy Fold
- Samsung Galaxy Fold teardown offers insight to the fast-evolving 5G RFFE design
Years in the making, the Galaxy Fold realizes Samsung’s ambition to create a new and potentially disruptive smartphone form-factor. The idea of a foldable design addresses a couple of smartphone use case pain points, namely (1) the conundrum of increasing display size at the expense of device ergonomics and (2) the consumer demand for a more immersive mobile experience while retaining portability. By engineering a flexible main 7.3-inch display, the Galaxy Fold design adds a new dimension to the tried-and-true smartphone form-factor by allowing users to transform the phone from a single hand experience into an immersive tablet-like experience by simply unfolding the device. Enabling technologies such as flexible OLED manufacturing, new display laminate film materials and rigid mechanical hinges are just a few that made this design possible. However, in this article, we will focus on the core electronics and 5G RF Front-End (RFFE) of the Galaxy Fold and demonstrate the evolution of the 5G RFFE design just within this calendar year.
The Samsung Galaxy Fold under analysis was sourced from the South Korean market – the first Galaxy Fold market to receive the 5G version. The ambitious new Samsung smartphone was ultimately released in September of 2019 [after a small delay to improve physical design and flexible display reliability] which places the devices in the group of “second wave” of first-generation 5G smartphone designs. While the core electronics are identical to the first several 5G devices previously discussed, the Galaxy Fold 5G RFFE offers an expanded RFFE design which included support for three common global Sub 6GHz 5G spectrum.
The top side of the printed circuit board (PCB) or motherboard captured above from the teardown shows the placement of the major chipset components of the Qualcomm from the Snapdragon 855 SoC to the X50 5G modem and branching into each of the two RF Transceivers (SDR8150 & SDR 8154). From there, the LTE and 5G radio paths continue through their own respective RFFE component chains until they arrive at the antenna. What is new here in the Galaxy Fold design is the use of a QPM4850 PAMiD (powe amplifier modules) and three separate QDM4850 FEMs (front end modules). This new RF design is different from all the previous Sub 6GHz design IHS Markit has analyzed before [as those used a common QDP/QDM5650 which supported the N77/78 Sub 6GHz 5G frequency].
After reviewing and studying the Galaxy Fold design more closely, it was discovered that the new 5G RFFE design contains support for not just one 5G frequency but three different ones. Samsung inserted three prominent Sub 6GHz global frequency support into the newly designed 5G RFFE. These included N41 (Sprint, North America), N78 (Korea & Europe) and N79 (China). Looking at the Bill of Materials (BOM), we can see that there are three distinct receive-diversity modules in the 5G RFFE, each tuned to the specific 5G frequency bands mentioned. A single PAMiD (QPM4850) design supports the 5G signal transmission from the device to the network. The reason for just one PAMiD and three FEMs in the Galaxy Fold is that during 5G operations, only one frequency will be used at any one time. The three FEMs provides capability to search for multiple 5G signals which enables global 5G roaming capabilities.
Below is a select list from the complete BOM that highlights the amount of Qualcomm components used within the Galaxy Fold. Beyond the transmit and receive modules; a QET5100 envelope tracker supports the power management of the QPM4850 PAMiD and multiple antenna tuners QAT3550 & 351x were employed to tune the fixed antennae in order to capture the precise 5G signals. This second-wave Qualcomm 5G design of the Galaxy Fold highlights their strategically important modem-to-antenna design solution which has been disruptive for the RFFE component market as no other vendor can offer RFFE components that span the entire baseband and RF chain.
Provisions for millimeter wave
As with previous 5G Samsung designs, there are hidden design elements in the Galaxy Fold that hints at spaces reserved for mmWave antenna modules. Internal structures and voids revealed in this teardown analysis points to at least 2 probable areas where mmWave antenna modules may reside (1) the space to right of the front facing cameras located to the top right corner of the 7.3-inch foldable display and (2) internal cavity of along the vertical sides of the device. This discovery would suggest that a mmWave version of the Galaxy Fold 5G may be produced and launched in markets such as the US where mmWave spectrum has already been reserved for use in 5G. However, it is worth noting that this particular sample of Galaxy Fold under teardown analysis only supports Sub 6GHz 5G and does not have the expected interconnections to accommodate mmWave antenna modules. Also, yet another combined mmWave plus Sub 6GHz design is entirely possible given the device size and capabilities of the Qualcomm 5G chipset.
5G RFFE evolving quickly
The pace of advancements in the 5G RFFE in 2019 has been quite impressive considering we are still within the first year of 5G handsets and network launches. This new tri-band 5G RFFE design discovered in the Galaxy Fold is indicative of a very vibrant and healthy 5G components ecosystem which is only going to accelerate as 5G becomes more mainstream. Later this year, we will see the second-generation 5G chipsets from Qualcomm (X55) come to market which will allow for low band 5G FDD support on carriers such as T-Mobile in the US. This updated 5G chipset will go further to integrate more 5G capabilities while driving down overall silicon content (and likely cost) of building new 5G smartphones. By offering a complete 5G RFFE solution, Qualcomm is winning the majority of 5G smartphone designs this year as the Qualcomm RF solution provides OEMs the ability to go to market sooner with their products [than if they had to piece together a complete 5G RFFE from existing RF component vendors by themselves]. The success of Qualcomm’s complete modem to antenna 5G design solutions will help to create more market competition amongst the established players in the RFFE space. Ultimately, additional RFFE competition will benefits everyone in the 5G ecosystem since it drives innovations and advancements in 5G design.
5G Opening new Design possibilities
At the heart of the Samsung Galaxy Fold design story is the fact that the decade-old smartphone industry still has the willingness to experiment with new form-factors and test new designs. In fact, the industry is banking on 5G to be the catalyst for a renaissance of smartphone design which ultimately may help jolt the stalled smartphone market back to growth. Existing smartphone design [the “flat & black” form factor of the past] hasn’t changed much over the years. Screen size has increased over time to accommodate consumer demands and support the consumption of new digital content that is reshaping the mobile experience. Given the potential of further improved speeds and latency performance of 5G networks [over that of existing LTE networks], there are many new and even un-realized applications that may capture the imagination of the smartphone industry. The Galaxy Fold is just one of many new designs to come and with the power of 5G connectivity and enabling RFFE technology like the ones from Qualcomm, the industry is poised for more diverse and exciting devices.
Appendix - Teardown Sequence