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CC1120: Customer evaluation questions

Fabio Gou
Expert 3060 points
Part Number: CC1120
Other Parts Discussed in Thread: CC1310, CC1190

Hi Experts, the customer is evaluating CC1120 products.

They have some questions.

"We are looking for long range communication solution. We expect to add external FEM in order to achieve >20dBm TX power at 900MHz for US market.
We have following questions about Ti 900MHz transceiver
1. Which chipset support antenna diversity? Transceiver or MCU make decision?
2. Which chipset support external FEM?
3. What is enhanced wake-On Radio? Which chipset support it?
4. What is coding gain in CC1120? What is the data rate limit in coding gain? Have any other chipset support it?
5. Do they support CCA or LBT? Could we tune the threshold of CCA or LBT
6. What is the max payload length? Is it 256byte?
7. What is the sensitivity difference between 2GFSK and 4GFSK at same data rate?
8. In CC1120 datasheet page 7, what is the difference between Packet mode and Transparent mode?
9. Do you have a RF driver for measuring sensitivity (1% BER) in demo board?
10. Did you add LNA in 900MHz chipset? What is the best sensitivity at 900MHz after adding external LNA?"

Thanks

  • +1
    TI__Guru* 81171 points

    I will answer the SW /packet engine related questions, and I will let someone else cover the rest:

    1)

    CC112x supports antenna diversity. See user guide for details

    2)

    Enhanced WOR is supported by CC112x and the feature is described in the user guide.

    5)

    CC112x support CCA and LBT and the threshold is programmable.

    The feature is described in the user guide

    6)

    CC112x supports infinite packet length mode

    8)

    In packet mode, the packet engine in the device takes care of preamble and sync word insertion/detection, CRC calculation etc.

    In transparent mode the raw data is simply available on a pin and the MCU needs to so all the processing (not recommended)

    9)

    No

    Siri

  • +1 in reply to Siri
    TI__Expert 3220 points

    Hi,

    3)

    Enhanced Wake on Radio enables the device to be in sleep and wake up with some periodically and listen for incoming packets without any help of the MCU. Refer to section 9.6 of technical reference manual for more information. https://www.ti.com/lit/ug/swru346b/swru346b.pdf? 

    4)

    Coding gain is also supported on CC112x devices and CC120x devices. See the following thread for more about coding gain.

    https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz-group/sub-1-ghz/f/sub-1-ghz-forum/497100/cc1200-vs-cc1120-sensivity. 

    7)

    We have not measured the sensitivity difference between 2-FSK and 4-FSK for our devices. Generally, 2-FSK modulation will have slightly better sensitivity compared to 4-FSK given the same data rate. 

    10)

    We have used CC1190 as an LNA with CC1120 and also with CC1310. We get 1-2 dB of improved sensitivity when using CC1190 as the front-end module.

    Regards,

    HG

  • 0 in reply to Siri
    TI__Expert 3060 points

    What is infinite packet length mode? I only find 256byte FIFO buffer in C1120 datasheet.
    Do CC1120 support three IO pins for controlling SE2425 FEM?
    (See attached file: SE2435L_202412K.pdf)

    SE2435L_202412K.pdf

  • 0 in reply to Fabio Gou
    TI__Expert 3220 points

    Hi Fabio,

    Infinite packet length enables the device design to transmit and receive packets longer than 255 bytes. Please refer to section 8.1.5 of the technical reference manual swru295e for more information.

    CC1120 has four GPIO's where GPIO1 is used as SO for the SPI interface when CSn is low. All the other three GPIO's can be used as general purpose pins. It is however better to provide the three control signals from the MCU instead so that there are some GPIO's available for debugging. We have a reference design for CC1120 together with CC1190 which also needs three control signals. See the reference design at the following link.

    https://www.ti.com/tool/BOOSTXL-CC1120-90#design-files

    Regards,

    HG