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TRF37D73: Regarding swiching time reduction between amplifier enable and powerdown mode

Maitry Khambhati
Intellectual 370 points
Part Number: TRF37D73
Other Parts Discussed in Thread: AFE7900EVM, , TRF1208, AFE7900, TRF37A73, TRF37B73

Hello support Team,

I am looking for the RF gain block which is having the internal fast bypass switching for Direct sampling transceiver ( AFE7900EVM ) with the gain requirement of 22-25 dB and lower frequency 30-60 MHz. 

I have found one Gain block of  TRF37D73 , which is having power down mode. 

I have below query regarding the switching time. 

1) For my initial stages, amplifier is in the enable mode. then in order to switch from enable mode to powerdown mode, ( switching) what will be the switching time. 

2) In similar way, from powerdown mode to enable mode, what will be the switching time.

Also, If possible, can you please let me know the suitable LNA , gain block amplifier with bypass switching which is having the fast switching time between enable and bypass mode( like in nsec)?

  • 0
    TI__Mastermind 22280 points

    Hello Maitry,

      The datasheet of our gain blocks list the enable/disable timing under PWD timing requirements:

      More information can be found at this thread for details on % rising and falling edge: e2e.ti.com/.../trf37d73-the-startup-time-of-the-device-by-controlling-the-pwdn-pin-of-trf37d73-and-trf37c75

      For faster switching speeds, take a look at TRF1208. It would look like you would need the differential output for the AFE7900. 

      Also, I have forwarded this thread to our RF amplifier team for additional inputs. 

    Thank you,

    Sima 

  • 0 in reply to SimaJalaleddine
    Intellectual 370 points

    Hi,

    As I want to control External amplifier by using AFE7900 RX Bypass output signal( which is CMOS LOGIC 1.8 V) . TRF1208 could be possible.  But the gain is not sufficient. my gain requirement is 20-25 dB.

  • 0 in reply to Maitry Khambhati
    TI__Prodigy 620 points

    Hello Maitry, 

    What is the max frequency and gain flatness required  ? I suggest TRF37A73 + TRF1208. This can work for max frequency  ~4GHz. It also gives ~1dB gain flatness in the pass band. This should be a better solution compared to a single-ended  high gain-block + balun.

    -Anil

  • 0 in reply to Anilkv
    Intellectual 370 points

    Hi,

    My frequency requirement is lower. and my total gain requirement is almost 32.5 dB. out of which fixed gain LNA gain requirement =10 dB while the bypass/enable gain block amplifier requirement is 22 dB approx. Actually my input dynamic range is minimum to maximum. so as per my input dynamic range, there is a requirement to have low fixed gain amplifier( of 10-12 dB) wuth the bypass gain block amplifier with a gain of 20-25 dB(approx.) , so that it is possible for me to bypass the high gain block when my input signal amplitude is higher.

    So, that' s why I am looking for a bypass amplifier with high gain 

  • 0 in reply to Maitry Khambhati
    TI__Prodigy 620 points


    Understood. I don't see many options for high gain GB with power-down / bypass options. You could cascade 2 TRF37A/B73 gain blocks to get the required gain. Do you have a 10dB LNA identified ? The line-up could look like this:

    1) LNA (10dB) + TRF37A73 (12dB) + TRF37B73 (14dB) + balun (-3dB) + AFE79xx

    If your link budgeting allows you to have a higher gain LNA (like QPL1002, 17dB gain), then you could have a simpler line-up like below:

    2) LNA (17dB) + TRF1208 (16dB) + AFE79xx