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TPS54386: 24V to 5V and 3.3V possible with TPS54386?

Aung Thet
Prodigy 195 points
Part Number: TPS54386
Other Parts Discussed in Thread: LM25011, TPS54302,

Hello all,

I am thinking of stepping down 24V to 5V (2A) and 3.3V(2A) directly with TPS54386-Q1.

However, the design examples in the data sheet only includes 12V to 5V, 3.3V configuration. And I have also looked at WEBENCH, but I am not able to find any two rails output design either.

Is it really feasible to do 24V to 5V (2A) and 3.3V (2A) configuration? 

Will there be any problem using TPS54386-Q1.?

Any cheaper, better alternative?

My budget is only $3 for the DC-DC converter.

Regards

Aung

  • 0
    TI__Guru**** 191445 points

    I can't think of any reason why you could not do 24 V to 5 V and 3.3 V using TPS54386-Q1.  Do you need automotive grade device?  There are definitely some alternatives.  It may be possible to get a lower BOM cost using to independent commercial grade devices.  I would have to know your total requirements.

  • 0 in reply to JohnTucker
    Prodigy 195 points

    Do you mean using two stages 24 V to 5V and then 5V to 3.3 V is cheaper than one power supply having dual outputs?

    Our budget is around $2 to get 5V - 2A and 3.3V 2A outputs from 24V input. Can you please recommend a solution?

    What do you need?

    Regards

    Aung

  • 0 in reply to Aung Thet
    TI__Guru**** 191445 points
    There are some very low cost 24 V single output converters. You need both 3.3 and 5 V at 2 A correct?
  • 0 in reply to JohnTucker
    Prodigy 195 points
    Yes, correct. Is it better to go direct from 24V to 3.3V , then another discrete IC to drop 24V again to 5V? or 24V to 5V, then 5V to 3.3V is better? What is the lowest cost option?
  • 0 in reply to Aung Thet
    TI__Guru**** 191445 points

    I used the Webench design tool. The lowest total BOM cost was to use LM25011 for both 5 V and 3.3 V rails. Total BOM cost was $1.79 + $1.82 = $3.61. This is a little higher than your request of $3.00, but Webench bases the BOM cost on 1K Digikey pricing. This is to provide "apples to apples" comparisons. If you have any significant volumes you can get lower cost for sure.

  • 0 in reply to JohnTucker
    Prodigy 195 points

    JohnTucker said:

    I used the Webench design tool. The lowest total BOM cost was to use LM25011 for both 5 V and 3.3 V rails. Total BOM cost was $1.79 + $1.82 = $3.61. This is a little higher than your request of $3.00, but Webench bases the BOM cost on 1K Digikey pricing. This is to provide "apples to apples" comparisons. If you have any significant volumes you can get lower cost for sure.

    How about TPS54302, isn't it cheaper? What is the difference?

    Regards

    Aung

  • 0 in reply to Aung Thet
    TI__Guru**** 191445 points
    You would think it would be cheaper, but Webench suggests that the BOM cost is $7.56 + $7.31 = $14.87. I don't generally support "pricing questions" as pricing varies wildly depending on your distribution channels, production quantity, etc., plus these TPS54386 alternatives belong to different product lines anyway. Technical questions are my area of expertise. If you are planning to build a significant quantity ( >100 k units a year or so), I'm sure you can get a discount.