LAUNCHXL-CC1352R1: Bad sensitivity

Michael O'Hearn

Part Number: LAUNCHXL-CC1352R1
Other Parts Discussed in Thread: CC2650, , CC1352R

I'm trying to verify the RX performance for the CC1352 for 802.15.4 at 2.4GHz.

I'm using one device as the TX and another device as the RX (DUT). Between the two devices is a variable attenuator. The DUT is in a shielded box.

For the TX, it is setup to send 20 octet packets at +5 dBm. By the time the signal gets to the RX side it is +3 dBm (when the attenuator is set to 0 dB). This was verified with a spectrum analyzer.

The attenuator is then adjusted until the PER is greater than 1%. At that point the RX sensitivity level is calculated by taking the RX power received with no attenuation (+3 dBm) and substracting the attenuator value when PER is greater than 1%. In this case the attenuator is 90 dB, thus the sensitivity level is (+3 dBm - 90 dB = -87 dBm). The data sheet states it should be -101 dBm.

To check the setup I've also made the same measurement on CC2650 board. The level is -100 dBm for PER of 1%. It matches the specification in the datasheet.

I can't imagine the CC1352 sensitivity level is so far off from the datasheet (-87 dBm measured vs -101 dBm stated in the datasheet).

Any suggestions to what is wrong or something to check?

For the DUT I'm connected to SMA contact, J7

The LaunchXL-CC1352R1 board does have an RF switch to route either the 1GHz or the 2.4GHz to the antenna. I haven't measured the control signal, but maybe it is not enabled for 2.4 GHz.

Please let me know.

Michael

over 6 years ago

0 PM over 6 years ago

TI__Mastermind 27145 points

Hi,

If you are using SmartRF Studio (2.8.0), it sets the Control Signal ( DIO30) automatically as per the mode selected.

Did you remove C482 (Disconnect Antenna path) before you measure the Sensitivity? If not you need to Remove C482 to use J7.

Thanks,
PM

0 Michael O'Hearn over 6 years ago in reply to PM

Intellectual 270 points

Hi,

Thanks for response.

I'm using 2.8.0. and C482 has been removed. C483 is mounted (to J7). I also measured the control voltage. It stays low for the mode and also during RX or TX. Both 1352R1 boards I have measure roughly the same (-87 dBm).

Michael

0 PM over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 27145 points

Hi,

Did you check at different Freqs?

Thanks,
PM

0 Michael O'Hearn over 6 years ago in reply to PM

Intellectual 270 points

Yes, at low, middle, and high channels (2405, 2445, 2480 MHz) with roughly the same results

Michael

0 PM over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 27145 points

Hi,

Could you please try to set the Transmitter Power to -10dBm (instead of +5dBm)?

Thanks,
PM

0 Michael O'Hearn over 6 years ago in reply to Michael O'Hearn

Intellectual 270 points

I don't know if it helps, but the chips are stamped with
XCC1352
R1F3
TI 74J
PF3L G4

and

XCC1352
R1F3
TI 79J
PH2F G4

Michael

0 PM over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 27145 points

Hi,

XCC1352 means it is Pre-released version. But it should be OK.

Please check bt setting the Transmitter Power at -5dBm or at -10dBm level.

Thanks,
PM

0 Michael O'Hearn over 6 years ago in reply to Michael O'Hearn

Intellectual 270 points

Hi,

No change is sensitivity level with TX Power at -10 dBm.

Michael

0 PM over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 27145 points

Hi,

OK, I will assign your post to the concerned engineer. He will get back to you.

Thanks,
PM

0 RGW over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 29560 points

Hi Michael,

The sensitivity should not be in the region of -87 dBm. I can re-measure this in the lab and reply to you asap. According to the data sheet, it should be -101 dBm so on the LaunchPad I would expect around -100 dBm.

Regards,
Richard

0 Michael O'Hearn over 6 years ago in reply to RGW

Intellectual 270 points

Thanks Richard

I look forward to hearing your results.

Michael

0 RGW over 6 years ago in reply to RGW

TI__Mastermind 29560 points

Hi,

Tested CC1352R with BLE PHY and measured an average of -97 dBm over 4 frequencies in the 2.4 GHz ISM band and with 3 different LPs. This is according to the data sheet that also specifies -97 dBm.

Recommend to use a test configuration with a signal generator to transmit the low level TX signal instead of using an attenuator unit, a shielded box and a radio unit as Tx. When the attenuator is configured with high attenuation such as 90 dB, the conducted receiver measurement level is difficult to precisely control due to the shielded box has limitations and emissions from the unit configured as a Tx sender.

Regards,
Richard

0 Michael O'Hearn over 6 years ago in reply to RGW

Intellectual 270 points

Thanks Richard for checking.

A few things:

We are using 802.15.4, not BLE. I did setup the devices for BLE, but the results are still poor.
We've tested a lot of devices using the method of attenuators. Although I mentioned we run it threw an attenuator, it actually is going through a series of atteunators, Fixed attenuators are located in the shielded enclosure and the adjustable one outside of them. In difficult situation we have a shield box for the TX and another for the RX. For this test I have even used separate computers, one for the TX and another for the RX. None of the extra items have helped.
We could use a signal generator for BER measurements, but we need RX CLOCK and RX DATA. Our preference is to use two CC devices as they should be properly setup to provide the complete packet (Preample, syncword, Data), exact modulation, etc.
We have verified the RX sensitivity setup using one CC1352 as the TX and a CC2650 as the RX. The sensitivity measured is the same as the stated in the data sheet. This verifies the setup is good.

As these are XCC devices, could something be wrong on the RX side?

Let me know.

Michael

P.S. We are doing this work for our customer, whom you know and have been in contact with about this problem.

0 RGW over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 29560 points

Hi Michael,
Do you measure the same sensitivity level on several CC1352 LPs ?
We checked this in the lab on a CC1352 LP and achieved expected performance.
There is something wrong here since there is about 15 dB missing in the sensitivity.
Regards,
Richard

0 Michael O'Hearn over 6 years ago in reply to RGW

Intellectual 270 points

We have two dev kits. The chips are XCC's. They both measure about the same.

I can't imagine a setup problem as we ave made similar type measurements before. Also, when using the same setup with a CC2650 as the DUT, it measures as per the datasheet.

Michael

0 RGW over 6 years ago in reply to Michael O'Hearn

TI__Mastermind 29560 points

I shall test this on a LP and supply you with a tested LP so we can correlate our test results.

//Richard

0 RGW over 6 years ago in reply to RGW

TI__Mastermind 29560 points

Hi Michael,
I have two new CC13532 LPs that I have tested and recorded the sensitivity level. If we cannot find a delta between the measurement setups, then I can send these to you or to the end customer.

Can you test the BLE PHY as well to see if there is a delta between Zigbee PHY ?

Are you testing with CC2650 as the Tx unit or CC1352 ?

Regards,
Richard

0 RGW over 6 years ago in reply to RGW

TI__Mastermind 29560 points

Hi Michael,
Have you had the opportunity to test the new board ?
Regards,
Richard

Other wireless

Other wireless technologies forum

LAUNCHXL-CC1352R1: Bad sensitivity