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LMH6517: How to program gain using SPI?

Cindy Wei
Prodigy 290 points
Part Number: LMH6517

Tool/software:

Datasheet Figure 52 (pg22) shows 4-bit address (A3..A0) and 8-bit data.  What do the address and data mean in terms of gain?  For example, if I want to program CHA gain=10dB and CHB gain=-5dB, what are the address and data for each setting?

On datasheet pg24, what are table3 and table4 talking about?

  • 0
    TI__Expert 3320 points

    Hello Cindy Wei,

       A3 to A0 are address of registers that needs to be written. To change gain keep all of them 0. Below are the few examples of address and data for each gain setting. Let me know if you have any other questions.

    Read/Write reserved CHANNEL SELECT ENABLE Gb5 Gb4 Gb3 Gb2 Gb1 Gb0 RES
    C7 C6 C5 C4 C3 C2 C1 C0 D7 D6 D5 D4 D3 D2 D1 D0
    CHA ON Min gain(Att = max) 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 00 80
    Max gain(Att = 0) 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 0 00 FE
    CHA OFF 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 00
    CHB ON Min gain(Att = max) 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 01 80
    Max gain(Att = 0) 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 01 FE
    CHB OFF 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 01 00
    CHA ON G=10(ATT = 12) 0 0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 00 B0
    CHB ON G = -5(Att = -27) 0 0 0 0 0 0 0 1 1 1 1 0 1 1 0 0 01 EC

    Regards,

    Hruday

  • 0
    TI__Prodigy 290 points

    There are actually just two addresses, 0x0 for CHA and 0x1 for CHB, referred by table3.  Table4 is for data.  I wish the datasheet could make it clear.  Thanks for the examples.

  • 0 in reply to Cindy Wei
    TI__Expert 3320 points

    Hi Cindy,

    We will take your feedback and will update in next revisions of our data sheet. Thank you!

    I am closing this thread.

    Regards,

    Hruday