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AFE5803: Channels to power down in Averaging Mode

Art Mecina
Genius 16655 points
Part Number: AFE5803

Hello Guys,

Good day.

Our customer is using the AFE5803 for an application and wants to optimize the power consumption. He know that he can turn-off unused channels by setting register functions. However, since he is using averaging feature (AVERAGING_ENABLE), he does not know which channels he can safely turn-off.

He have inputs coming in on channels 3 + 4 (which comes out on channel 4), and another pair of inputs coming in on channels 5 + 6 (which comes out on channel 5). Does this mean that he can turn off all but channels 4 and 5? Does that apply for both the ADC and VCA power-down, as well as the LVDS signaling power-down? Or do he need to leave channels 3-6 on for the ADC and VCA, since those channels are receiving inputs?

Thanks in advance!

Art

  • 0
    TI__Genius 12025 points

    Hi,

    Thanks for using AFE5803 device.

    We will reply to you very soon.

    Thank you!

    Best regards,

    Chen

  • 0 in reply to Chen Kung
    TI__Genius 16655 points

    Hi Chen,

    Thank you for looking into this!

    Art

  • 0 in reply to Chen Kung
    TI__Genius 12025 points

    Hi,

    Thanks for using AFE5803 device.

    For your question about AFE5803 device.

    AFE5803 Channels power

    CH3~6 need to be active. Otherwise average doesn’t work.

    Thank you!

    Best regards,

    Chen

  • 0 in reply to Chen Kung
    TI__Genius 16655 points

    Hi Chen,

    Thank you for the response.

    Just to confirm, if our customer are using averaging on channels 3 and 4, then channels 3 through 6 need to be configured as active. Does that apply to all of the registers (ADC_PDN_CH<7:0>, POWER_DOWN_LVDS_CH<7:0>, and PDN_CH<7:0>)?

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 16655 points

    Hi Chen,

    Good day.

    Any update on this follow-up inquiry?

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 16655 points

    Just like to follow-up on this one.

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 12025 points

    Hi,

    Clearly for one example only is:

    if the customer wants to do averaging on channel 3 and channel 4,

    ADC_PDN_CH3=0, and ADC_PDN_CH4=0

    POWER_DOWN_LVDS_CH4=0

    PDN_CH3=0, and PDN_CH4=0

    others can be added if neeced.

    Thank you!

  • 0 in reply to Chen Kung
    TI__Genius 16655 points

    Hi Chen,

    Good day.

    Our customer have a follow-up inquiry on this one. He has some clarifications. According to him,  if channels 3+4 are being averaged together, he should power down LVDS for channel 3, leaving channel 4 powered on. He done exactly that but it does not work.

    What he's actually doing is averaging on channels 3+4 and also channels 5+6. He is expecting therefore, that he could power down channels 3 and 5, leaving channels 4 and 6 powered on. However, this doesn't work. Instead he need to power down channels 3 and 6, leaving channels 4 and 5 powered on. He find it to be a discrepancy.

    I will refer the customer directly to this post. It would be best if he can communicate directly his scenario.

    Thanks for the assistance!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 12025 points

    Hi,

    Please refer to AFE5803 datasheet page 26,

    when using Averaging mode (AVERAGING_ENABLE=1)

    Ch1 and Ch2 Averaging to Channel 3 LVDS output pins

    so POWER-DOWN_LVDS_CH3=0

    Ch3 and Ch4 Averaging to Channel 4 LVDS output pins

    so POWER-DOWN_LVDS_CH4=0

    Ch5 and Ch6 Averaging to Channel 5 LVDS output pins

    so POWER-DOWN_LVDS_CH5=0

    Ch7 and Ch8 Averaging to Channel 6 LVDS output pins

    so POWER-DOWN_LVDS_CH6=0

    If in the case above, then

    then you can turn off

    POWER-DOWN_LVDS_CH1=1

    POWER-DOWN_LVDS_CH2=1

    POWER-DOWN_LVDS_CH7=1

    POWER-DOWN_LVDS_CH8=1

    Thanks!

    Best regards,

    Chen