CC2541 and Bluetooth Qualification

Hello John,

TI is unable to provide legal advice. The aforementioned page has a link to the BT SIG compliance program website. For your benefit, I've added it here: www.bluetooth.org/.../compliance-program

Best wishes

Hi JXS

The aforementioned link suggests that if a reference design is strictly followed, the customer does not need to have the produce qualified. Which reference design is it referring to? Is it the circuitry reference design? I thought the SIG qualification isn't concerned with hardware circuitry decisions.

Thanks

Hello John,

If you've replicated the CC2650EM_7ID layout (inside the white silkscreen outline) and the exact same antenna layout, then you can use the CC2650EM_7ID RF-PHY QDID. If you have modified or used a different ref design, then you only need to perform the RF-PHY testing on your HW. However, in any case, you will still need to obtain a Declaration ID regardless of which Components you combine with in your listing.

For further questions, I suggest consulting with a Bluetooth Qualified Expert (BQE).

Best wishes

Hi

I'm actually using the CC2541. But, for the sake of discussion suppose it's the CC2650, would the exact PCB layout of CC2650EM_71D have to be used in order to avoid the qualification process? Otherwise (including a small change in a capacitor or a completely different layout) only RF-PHY testing will be needed?

Thanks

Hi John,

Sorry, I missed that you are CC2541, but the same principle applies. You can modify the HW layout and still reference the Host & Profile QDID's, but, yes, you will need to do the RF-PHY testing. The BLE Stack has the hooks to perform RF-PHY via PTM or Host Test, for example. Also, RF-PHY testings a smaller subset of the full testing.

Note that if you are able to reference a QDID in your listing, you still need to complete the Bluetooth listing process, which includes obtaining a Declaration ID (DID). A DID is required regardless of the testing requirements.

Best wishes

Hi JXS,
I am struggling to understand the PCB trace antenna and RP PHY re-qualification of the CC2650EM-7ID. I have looked at the SIG's RF PHY test specification (as well as the core spec) and both state that for the RF PHY test a 50 ohm connector (either in the design or temporarily added) is to be used for RF PHY tests. In this is the case, the antenna would never gets tested, so if we change the antenna why would we need to re-qualify the RF PHY?

Thank you,
Jon

Hello Jon,

You would add the connector after the antenna passives. I'll check with our HW team for more details, but due to the holidays it could take a bit longer.

Best wishes

Yep, I'm clear on the connector being after the matching/balun passives. To be sure, my question is why do you need a RF PHY re-qual if you only change the PCB trace antenna?... From the BT SIG test specs the RF PHY qual is done hooked directly up to a 50 ohm connector, which yes, should be after the matching passives, but is before the PCB trace antenna (PCB trace antenna would have to be disconnected to hook tester up to connector and be impedance matched).

Thank you,
Jon

Hi Jon,

As JXS mentioned, the BLE test spec mentions that any changes to qualified designs must be reviewed by the BT SIG. See the pdf linked here www.bluetooth.org/.../DownloadDoc.ashx

BQEs are excellent resources for working through the qualification process. If you have further questions, I would suggest consulting a BQE
www.bluetooth.com/.../qualification-testing-services

I agree with JXS and Sean, contact a BQE for accurate information regarding this, we cannot give legal advice.

We have design just gone for BT Sig Testing based on the CC2541.

Currently this is failing BT Sig compliance as the low channel Frequency is slightly off (Should be 2402Mhz but measurement sure 2401.6Mhz).

Does anyone have suggestions to what might cause this. I understand there is an RF TUNE register, but it is not exposed as part of the BLE stack. Wondering where I should be focussing my attention in trying to resolve this.

Best Regards

Rob

Hi,

what frequency offset do you have on the other channels? If the other channels also are off, you might have to consider to optimize your crystal load for the 32 MHz crystal. 

Not sure what you mean with lower limit for BLE devices. BLE has 40 defined channels in its spec to fit in the 2400-2483.5 MHz band and 2402 is the lowest frequency channel. 2480 MHz is the highest frequency channel.

hi Charlotte,

Changing the crystal load for the 32Mhz seems to have no affect.

Any other suggestion, could this occur due to the antenna stage?

Rob

Hi Rob,

You said it's 2401.6Mhz, but did the device pass FCC Part 15 though?

Regards,

John

Haven't done the FCC or EN tests yet - on hold. But I am getting somewhere with this......

After exhausting some capacitor changes I have subsequently removed the crystal and capacitors from the TI USB Dongle CC2540 module and placed them on my design. This looks to have corrected the issue. The Crystals should be the same on our build but I am reviewing with the assembly house to see if there is a supply issue.

I'll post back when I am happy with the results just for everyone's reference.

Regards

Rob

Do keep us posted.

Regards,

John