BOOSTXL-CC1120-90: Not transmitting at correct power using smart RF

george clarkson

Part Number: BOOSTXL-CC1120-90
Other Parts Discussed in Thread: CC1120, CC1190

I've just obtained the BOOSTXL-CC1120-90 EVal kit and connected it using smart RF studio. following the instructions in swra492, I have:

Place Jumper on P6-1 to P6-2
Place Jumper on P6-3 to P6-4
Place Jumper on P6-7 to P6-8
Place Jumper on P6-11 to P6-12
IOCG0 = 0x73 in SmartRF
IOCG2 = 0x33 in SmartRF

I'm transmitting at 915MHz which is in the middle of the band, Smart RF studio thinks the output power should be 26dBm, which matches the data sheet, however, I am only seeing a transmission of around 5-8dBm through cabling. I've tested the cable with other products and they seem to be fine, so I'm a bit curious as to why I'm not getting the correct power from the device.

over 5 years ago

0 george clarkson over 5 years ago

Intellectual 830 points

I noticed by going through the forums that I need to remove R8 & R9 and short R7 as I'm not running a sigfox application. I have done this and gained a small power boost up to 13/14dBm but this is still down from the 27 I was expecting

0 george clarkson over 5 years ago in reply to george clarkson

Intellectual 830 points

Also where can I find the BOM for converting the board for 868? I know that I need to change L13, C59 & C60 but I don't know what values to use the reference design only contains a BOM for 915

0 TER over 5 years ago in reply to george clarkson

TI__Guru**** 317180 points

If you check the schematic: www.ti.com/.../swrr145 you will see notes for what has to be changed between 868 MHz and 915 MHz.

Could you verify the jumper placement on P6 as pr the schematic? If I'm not mistaken only 3 jumpers should be mounted here. Also measure the voltage level on PA_EN, LNA_EN, HGM to verify that they are correct.

0 george clarkson over 5 years ago in reply to TER

Intellectual 830 points

I was looking at the SWRR145 files, the schematic states "Don not Mount L13, C59 & C60 for 915MHz Design. L13, C59 & C60 for 868MHz Design only. Refer to corresponding BOMs for values" however in the BOM folder there is only the BOM for 915MHz. I know what to change but I don't know what to change them to.

The jumpers are configured to p6-1&p6-2, p6-7&p6-8, and p6-11&p6-12. and IOCG0 and IOCG2 are configured correctly in SmartRF.

Checking the voltages:
HGM is 3.2V (checked at p6-1)
LNAEN is 0V (checked at p6-7)
PAEN is 3.2V (checked at p6-11)

0 TER over 5 years ago in reply to george clarkson

TI__Guru**** 317180 points

Sorry, since the alternative part numbers for 868 MHz are given for most other components I overlooked that it was not given for these 3. YOu can take a look at to get a starting point. The 2. harmonic notches (L13/ C59, L9/ C60) are somewhat dependent on the layout so it could be that the values have to be adjusted slightly to be optimal for the boosterpack.

But before you start looking at 868 MHz I would try t o find out why you get an unexpected result on 915 MHz. Are you able to remove the SAW filter and measure the output power from the CC1120 part of the design?

0 george clarkson over 5 years ago in reply to TER

Intellectual 830 points

it does appear to be that the output from the cc1120 that is down. Removing the SAW filter and transmitting without the range extender enabled, and the TX power set to 15dBm, give an output of only 0dBm

0 TER over 5 years ago in reply to george clarkson

TI__Guru**** 317180 points

Strange. Does the spectrum looks normal when you measure on the CC1120 output?

0 george clarkson over 5 years ago in reply to TER

Intellectual 830 points

it looks fine just lower than it should be.

0 TER over 5 years ago in reply to TER

TI__Guru**** 317180 points

Are you able to use some of the products/ instruments you have as input to the CC1190 part to verify that you are able to get ~26 dBm with the correct input power?

0 TER over 5 years ago in reply to TER

TI__Guru**** 317180 points

Closing this thread due to inactivity.

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BOOSTXL-CC1120-90: Not transmitting at correct power using smart RF