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CC2640: Smart Lock Reference Design ((TIDA-00757) HW/RF and SW question

Part Number: CC2640
Other Parts Discussed in Thread: TIDA-00757, CC2650EM-5XD-RD, ,

Looking at the updated TIDA-00757 "Smart Lock Reference Design Enabling More Than Five Years of Life on Four AA Batteries", had some  HW/RF and SW questions.

1. Looking at p. 3 of the Smartlock Schematic (tidrmq3.pdf), I believe the RF Frontend is 4XS. Is that true?

2. If so  is  the RF Frontend to get the best BLE performance  the 5XD? 

3. Is the best way to evaluate  BLE RF performance with SmartRF06 + cc2650em-5xd-rd ?  Or can we modify TIDA-00757?

4. If we want to use an SMA Antenna on cc2650em-5xd-rd or TIDA-00757, can we just modify the 0 Ohm resistors to reroute (and populate SMA connector)?

5. Does TI recommend any particular SMA Antenna?

6. Is there any plan to port the TIDA00757-Firmware (from ) from CC2640 to CC2640R2?

Thanks in advance!


  • Hi Joe,

    1. The design is using single ended RF with external biased (XS), which is also demonstrated in the CC2650EM-4XS reference design. Note that the "4" is only describing the QFN size in that particular reference design and is not tied to the RF configuration or performance.

    2. An overview of the RF configurations can be seen here: . What the best option for a BLE application is depends. Most BLE products are running at 0 dBm TX power, in which case it does not make a difference whether you are using differential or single ended configuration. The difference in sensitivity between XD and XS is not much, and between ID and XS the performance is the same. The single ended option is a lot less complex and easier to implement, especially if the board designer has limited RF experience.

    3. Yes, you can buy the CC2650EMK-5XD. I would however recommend using the CC2640R2F for new BLE projects. I would start buy getting a CC2640R2F LaunchPad and evaluate if the performance of that board is satisfactory for the product at 0 dBm TX power. If it is, the customer will get the same performance if the use single ended with external bias in their product.

    4. Yes.

    5. Any 50 ohm antenna designed for 2.4 GHz will work.

    6. Not that I know of.