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Atmel SAM A5D26 power option from TI

Saqib Mohammad
Expert 4040 points
Other Parts Discussed in Thread: TPS65023, TPS65020

Hey Team,

I am trying to find what the best way to power a Atmel SAM A5D26 would be using as few ICs as possible, what would be the most appropriate PMIC for the job, and do we have any reference designs for this application?

Thank you for your help in advanced!

best regards,

Saqib

  • 0
    TI__Expert 8730 points
    Hi Saqib,

    Could you please provide me the voltage rails and load requirements for Atmel SAM A5D26 ?

    Regards,

    Murthy
  • 0 in reply to Krishnamurthy Hegde
    TI__Expert 4040 points
    Hi Murthy,

    At the moment all we know is what is in the SAMA5D2 datasheet, we do not have any other detailed requirements.

    datasheet: ww1.microchip.com/.../60001476A.pdf

    Do we have anything that can address the typical power rails and sequencing on page 42 and 43?

    thanks,
    Saqib
  • 0 in reply to Saqib Mohammad
    TI__Mastermind 30280 points
    Saqib,

    Without a detailed power tree and sequencing, the TPS65023 is the best option we can promote. All of the output voltages are flexible (HW pin-strapping or feedback resistors) and the sequencing can be performed with RC delays or via I2C for non-critical rails.

    Without a simpler block diagram/power tree from you or the end customer, it would take me some additional time to review the SAMA5D2 datasheet in detail to provide you a proposal specific to this processor family.
  • 0 in reply to Brian Berner
    TI__Expert 4040 points

    Hey Brian,

    See below for the requirements.

    Power rails for ATSAMA5D2x - values below are estimated typical requirements

     

    Switching:

    3.3V @ 0.15A VDD_IO *1*  

    1.35V @ 0.1A VDD_DDR *2*

    1.2V @ 0.35A VDD_CORE *3*

     

    LDO:

    1.8V/3.3V 30mA - for eMMC, voltage controlled by input on PMIC 

    3.3V @ 30mA *1* 

    2.5V @ 50mA on/off software controlled 

     

     *X* indicates power up order, around 2ms between rails. 

     

    The current solution can provide: 2A, 1.5A, 2.5A for switcher, and 300mA per LDO. We don't need to match those requirements, but that is the alternative at the moment,

     

     

    Thank you for your help!

    best,

    Saqib

  • 0 in reply to Saqib Mohammad
    TI__Mastermind 30280 points

    Saqib,

    As you mentioned offline, the input voltage is 24V and we are assuming there is a 12V rail in the system. 

    Since the current requirements are low, I will recommend the TPS65020 (1A max on DCDC1) instead of the TPS65023 (1.7A Max on DCDC1).

    NOTE: the maximum input voltage to the TPS65020 is 6.5V so this design may require a pre-regulator to get down from 12V to 6.5V before the PMIC.

    To match the voltages required, pin-strap:

    • DEFDCDC1 = VCC (3.3V)
    • DEFDCDC2 = Resistor divider to get 1.35V
    • DEFDCDC3 = GND (1.3V) or resistor divider for 1.2V exactly
    • LDO1/2 = Set by I2C (need to be disabled by default for eMMC and the SW-controlled LDO requiring 50-mA)
    • VRTC = 3V nominal (listed as 20-mA output, so please verify this will meet 3.3V, 30mA requirement for sequence *1*)

    Please notify me if any hard requirements are missed by this suggestion.

    If a Wide VIN part is desired by the customer, I suggest you look at one of the TPS433x devices that are automotive qualified (and support up to 30/40V input).