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AFE5816: fixed gain/fixed-attenuation

Needhu Gunasegaran
Intellectual 2710 points
Part Number: AFE5816

Hi Team,

Could you please Answer the following questions,

  • If I chose the fixed-gain mode for medium-power (9.3.5.3.1) and choose, for example, the gain code 64, then what is the mitigation and the reinforcement?
  • If I have chosen 63, then I have an attenuation of -8 + 63 x 0.125 = -0.125? How then is the reinforcement?
  • If I chose fixed attenuation mode (9.4.5.5) (see Table 9.), then I can put a value of 0-64 (instead of 0-63) in the register ATTENUATION_x and then get the formula -8 + 64 x 0.125 = 0dB?
  • Is there a precedence rule for gcode entries in the registers MANUAL_GAIN_DTGC / ATTENUATION_x?
  • How can I set the minimum gain of + 6dB (Attenuation: -8dB, Gain + 14dB)?
  • Electrical Characteristics: TGC Mode, page 13:

Channel-to-channel phase matching 15MHz signal: 11 degrees
Which phase difference do I have, e.g. at 600kHz?
Can one calculate the value over a Delay?

Thanks you in advance,
Needhu

  • 0
    TI__Mastermind 49176 points
    Hello Needhu,

    Regarding the questions:

    for questions 1 and 2, Can you please clarify the terms mitigation and reinforcement?

    3. In fixed attenuation mode, ATTENUATION_x field can take values from 0 to 63.

    4. Fixed gain mode refers to fixed LNA + fixed attenuator. In this mode the device gain is set directly by writing a gain code in the MANUAL_GAIN_DTGC register. Refer to section 9.3.5.3.1 for the gcode split between the LNA and the attenuator.

    5. To set minimum gain of 6dB in programmable fixed gain mode, set MANUAL_GAIN_DTGC = 0.

    6. a. This is delay variation 11/360*66ns.
    b. The phase difference at 600Khz is much smaller. You can use the above delay varation data as a guideline.
    c. Refer to the calculation.
  • 0 in reply to Praveen Aroul
    TI__Intellectual 2710 points
    Hi Praveen,

    Thank you very much for your quick reply.
    Sorry, Google translate did work very well here. I will try to clarify these questions.

    - If I chose the fixed-gain mode for medium-power (9.3.5.3.1) and choose, for example, the gain code 64, then what is the attenuation and the gain?
    - If I have chosen 63, then I have an attenuation of -8 + 63 x 0.125 = -0.125? How does the gain change then?

    in 6.c, which calculations are you referring to?

    Thank you very much.
    -Needhu
  • 0
    TI__Mastermind 49176 points
    Hi Needhu,

    I am assuming customer was able to get the remaining questions answered from the datasheet directly.
    If there are any follow-up questions, feel free to post them as a new question / related question.