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LP87524-Q1: What's the current limit for each channel

Elec Cheng
Expert 7055 points
Part Number: LP87524-Q1

Hi Expert,

I don't really understand what's the current limit for each channel. I don't see clear description about this. what does it mean by "The maximum output current from....phase configuration"? The total current is less than 10A and for the same time each channel output current is less than 4A or 3A depending on input voltage  if I use 4 1-phase?

As for LP87524b/j/p-q1, things are a little different as below. Are the output current limit are fixed as below? Only depending on input voltage sometimes?

BR, 

Elec Cheng

  • 0
    TI__Expert 6700 points

    Hello Elec,

    Thank you for reaching out, and happy holidays. Our engineering team currently has limited staffing now through January 3rd. We will provide feedback no later than January 7th.

    Regards,

    Alex

  • 0
    TI__Genius 11020 points

    Hello Elec,

    Current limits per channel depend on the OTP configuration. TRM documents (Technical Reference Manual) for each OTP spin shows the values for that particular part number. 

    What part number specifically are you interested to know?

    Thanks.

    Regards,

    Tomi Koskela

  • 0 in reply to Tomi Koskela
    TI__Expert 7055 points

    Hi Koskela,

    I don't really understand what the OTP means. But as you can see above, LP87524 has different versions, such as -B,-J,-P, they have different current limit. My question is, for a specific version, the output current is changeable or not?

    And our customer's requirement is as below,

    • 1.8V/2A
    • 1V/1.5A
    • 1.2V/4A
    • 2.2V/1.5A

    Do you have better choice for that?

    BR,

    Elec Cheng

  • 0 in reply to Tomi Koskela
    TI__Expert 7055 points

    Hi Koskela,

    just confirm with you, is the output current of LP87524-Q1 programmable? It seems that -B/J/P version cannot meet the current requirement. Thanks!

    BR,

    Elec Cheng

  • 0 in reply to Elec Cheng
    TI__Genius 11020 points

    Hi Elec,

    OTP means the One Time Programmable memory, a non-volatile memory that contains the configuration (output voltages, maximum currents, SW frequency, sequencing etc). We have hundreds of OTP spins with different settings for this product family (LP8752x/LP8756x).

    LP8752x current limits are not configurable by user. Limits are set by the OTP memory that is programmed in the factory. 

    If they can configure the output voltages through I2C before starting bucks, they could use for example LP87524T-Q1. This part number has 2MHz switching frequency as opposed to the LP87524J/P/B which have 4MHz SW frequency to support radar applications.  Note they can only write to the registers which are volatile memory, so on power down the setup will be lost. 

    You can check the detail on the configuration on the TRM: https://www.ti.com/lit/ug/snvu606a/snvu606a.pdf

    You can also check is there suitable LP87564x version that they could use. LP87564x current limits are user configurable. 

    Thanks.

    Regards,

    Tomi Koskela

  • 0 in reply to Tomi Koskela
    TI__Expert 7055 points

    Hi Koskela,

    Good to know this. Since we have so many versions, how can I know them when selecting? Do you have a file or tool to help select? 

    BR,

    Elec Cheng

  • 0 in reply to Elec Cheng
    TI__Genius 11020 points

    Hi Elec,

    Most of the OTP spins are for specific customer and use case and are not publicly available, we call them custom spins. You can see the available "catalog" LP87524/LP87564 versions/part numbers on the end of datasheet in the order information. TRMs for each orderable shows the OTP setup and helps you select the correct version.

    I have checked all OTP spins we have released and none of them match the voltages customer would need. So the option is to use existing LP87524/LP87564 spin with sufficient output currents and configure the output voltages through I2C to match the needed values.

    Thanks.

    Regards,

    Tomi Koskela