Table Of Content

INTERNAL USE MT6631 WIFI Ant-Swapping design notice V0.1 For MT6785 / 6767 2019/01 CTD/RF/RF1  1. Antenna Swapping Concept  2. Front-end architecture  a. SWAP architecture b. Loss estimation c. BOM cost / Layout evaluation d. Antenna placement  3. WIFI 2/5G TRX Performance  4. SW : swap control/ calibration / threshold  5. Tool：SP meta /產測ATE tool INTERNAL USE 1 Antenna Swapping Concept  Probe the signal quality of another available antenna if the signal quality (RSSI)of working antenna is less than weak signal threshold over a trigger period.  Switch to the antenna which signal quality is greater than current used one by a quality threshold.  Apply the selected antenna only when other radios are idle to mitigate the interference.  Switch back the original antenna if the signal quality of selected antenna are poorer than the original in an observation period. INTERNAL USE 2 A/G Band Antenna swapping front-end • Pros: Swapping antenna at ant performance degraded scenario. • Cons: Degrade TRX performance due to larger front-end loss. • Bluetooth TRX path will also be switched by WIFI antenna swapping control (Same path as WF2.4G) Diplexer (WIFI /GPS) INTERNAL USE 3 MT6785 Antenna swap architecture WIFI dedicated Ant-2 LTE antenna sharing Diplexer Diplexer (WIFI /GPS) (WIFI /GPS) INTERNAL USE 4 LTE + WiFi sharing antenna SP8T schematic INTERNAL USE 5 Front-end loss estimation • Estimate front-end loss from component datasheet (not include trace loss). • Compare with default architecture , main antenna has additional 0.8~1dB loss , second antenna has additional 0.38~0.45 dB loss. • Front-end loss increase make Tx power and Rx sensitivity performance degrade at ant port (Ant-swapping architecture performance worse than default type). Front-end loss Diplexer Diplexer Total FE loss default type TRx loss FBAR SDPT estimate (dB) (A/G Band) (GPS/WF) antport (ideal) FE loss(ideal) degrade 2.4G main antenna 1.2 0.68 0.5 0.56 2.94 1.93 -1.01 2.4G second antenna 1.2 0.68 0.5 2.38 1.93 -0.45 5G main antenna 0.78 0.7 0.42 1.9 1.1 -0.8 5G second antenna 0.78 0.7 1.48 1.1 -0.38 INTERNAL USE 6 BOM cost calculate (compare with default architecture) ▪ For Ant-swap architecture, key component change as below - Remove original Triplexer =0.06 USD - Add additional 2 Diplexer =0.05 USD*2 - Add additional 1 SPDT =0.05 USD ▪ Total key component cost rise is around 0.09 USD - 0.09 USD = 0.05 (SDPT) + 0.05*2 (2 Diplexer) – 0.06 (Triplexer) INTERNAL USE 7 Layout evaluation • For additional Diplexer and SDPT, it needs more layout area than default type phone. • Internal phone has same front-end architecture as below picture. • For ant swapping placement , we suggest to copy placement from Talbot . • Layout area is around 10mm*25mm , MT6631 to diplexer length is around 20mm. Internal phone- type A Internal phone - type B INTERNAL USE WIFI 2nd Antenna placement suggestion WIFI dedicated Ant-2 or LTE+WIFI sharing antenna Area of Hand-Effect 9 INTERNAL USE