3 Replies Latest reply on Feb 3, 2020 2:46 AM by AnjanaM_61

    CYBT-483039-02 documented PA/LNA control interface

    GrCa_1363456

      Where are the options to control the PA/LNA on the CYBT-483039-02 documented?

       

      The instructions to enable the PA to increase transmit power are provided in

      Are there additional commands?

      - How to disable the Power Amp

      - How to enable the Low Noise Amp

      - How to disable the Low Noise Amp

       

      Are there recommendations on chip power output when using PA/LNA to maximize transmit power or receive sensitivity?

       

      Are there additional notes to control power of the base CYW20719 chip?

      - A summary of the chip power options is @ Change List CYW20719-B1 and CYW20719-B2

      - Methods to communicate and change chip power @ BLE Proximity Profile - CYW20719 / CYW20735 and How to change the frequency & power level of 20719 with some additional links to additional support and more comments

       

      Reference the PA/LNA datasheet https://www.skyworksinc.com/-/media/SkyWorks/Documents/Products/2301-2400/RFX2401C_204359B.pdf

       

      Aside: It's not clear which chip CYW20719-B1 or CYW20719-B2 in on the CYBT-483039-02 module Reference Which version of CYW20719 is on CYBT-483039-02 ??

       

      Greg

        • 1. Re: CYBT-483039-02 documented PA/LNA control interface
          AnjanaM_61

          Hi Greg ,

           

          CYBT-483039-02 uses CYW20719 B1 as main chip and will be supported in WICED Studio SDK . Please refer Table 34 of module datasheet :  https://www.cypress.com/documentation/datasheets/cybt-483039-02-ez-bt-xr-wiced-module

           

          To enable PA/LNA , you have to call the code snippet as mentioned in the KBA which you already referred :  WICED Studio: Platform Files for CYBT-483039-EVAL – KBA223747 

           

          You may use the API wiced_bt_set_tx_power & wiced_bt_dev_set_adv_tx_power (refer wiced_bt_dev.h ) for controlling the required Tx power.

           

          Thanks,

          Anjana

          • 2. Re: CYBT-483039-02 documented PA/LNA control interface
            GrCa_1363456

            Anjana,

             

            Thanks for addressing a couple of the individual questions.

            Two questions that weren't answered from the original post:

             

            1) Are there additional commands to control the PA/LNA?

            - How to disable the Power Amp

            - How to enable the Low Noise Amp

            - How to disable the Low Noise Amp

             

            KBA223747 only tells how to turn on the PA. It does NOT tell how to turn off the PA or how to turn on or off the LNA. It would additionally be helpful to understand the registers that are being written and the importance of each bit.

             

            2) Are there recommendations on chip power output when using PA/LNA to maximize transmit power or receive sensitivity?

            To expand on this second question; with the PA enabled, should the CYW20719 chip be set to maximum transmit power of 4dBm (...or 6dBm if using CYBT-483056 with CYW20719-B2) to achieve maximum total transmit power?

            Is there any danger of over-driving the PA input? Table 2 RFX2401C Absolute Maximum Ratings in the PA/LNA spec linked above, states a Maximum input of +5dBm. I'm guessing this shouldn't be an issue with the B1 silicon. Is there 1dBm loss in the path from CYW20719B2 chip to PA/LNA that would allow full tx power into the PA/LNA without concern for damage?

             

            Greg

            1 of 1 people found this helpful
            • 3. Re: CYBT-483039-02 documented PA/LNA control interface
              AnjanaM_61

              Hi GrCa_1363456 ,

               

              1) How to disable the Power Amp , How to enable the Low Noise Amp , How to disable the Low Noise Amp

               

              A: No, there are no additional commands.  The PA/LNA for this module is not a configurable device, it is a boost for outgoing and incoming signals. 

              If you disable the PA/LNA, you will not have any BT/BLE activity.  There is no option for passthrough for the PA/LNA on this module.

               

              The KBA does not tell how to turn on the PA/LNA, it describes how to enable the interface for the TX and RX signals to the PA/LNA.  Without the signaling, the output power would be significantly degraded.  The PA/LNA for this module is always on, but the boost for the output will not occur without the control lines enabled and running in sync with the CYW20719 silicon Bluetooth interface. 

               

              2)

               

              The CYW20719 has a maximum output power of +4dBm.  To maximize the output power, you would set the silicon device output power to the maximum level and the PA/LNA will boost this by the defined PA amount, which is a maximum of 25dB boost.  The boost is not configurable, the maximum term is because there is part to part variation for the PA/LNA.  NOTE that if you do boost the module to 4 + 25 dBm = 29dBm, you will be in violation of a number of regulatory limits.  To this end, the output power for 20dBm is the limit for US and Canada, 10dBm is the limit for most other regions that leverage ETSI requirements.  NOTE that the saturated output power of the PA/LNA is 22dBm, so even if you configure to greater than this, it will be saturated and will not be able to output more than 22dBm.  The 25dBm boost still applies, because you can have a negative signal inputted and it will boost it by the maximum amount not to exceed 22dBm total Pout. 

               

              Please Note: If the customer is looking to have high power and low power in the same module, this is not the best part for them as it is design to specifically boost to the maximum allowable output power for BT/BLE.

               

              Thanks,
              Anjana

              1 of 1 people found this helpful