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LM3671-Q1 1.25V

WhiteHorse
Genius 4430 points
Other Parts Discussed in Thread: LM3671-Q1, LM3671, LM2734-Q1, LM2734, TPS62003, TPS62260-Q1

We have a customer that really likes the efficiency, solution size and price of the LM3671 fixed output 1.25V version, but needs industrial temp.  The standard LM3671 only goes down to -30 deg C.  There is a LM3671-Q1 version that the website implies has a 1.25V version available, but there is no official part number.  Is one available?  If not could one be?  Quantities for this project are 20K in 2013 and 100K in 2014. 

Thanks,

John

  • 0
    TI__Guru 71526 points

    Hi John,

      Seems the part numbering designations have not yet been assigned, not even for the adjustable version.  While I'm investigating this, you might want to look at the LM2734-Q1, as it is now available, although you will have to add the voltage divider to set VOUT: http://www.ti.com/product/lm2734-q1 .

    -Leonard

     

  • 0 in reply to LeonardEllis
    Genius 4430 points

    Hi Leonard,

    Thanks for your help.  I checked out the efficiency of the LM2734 on Webench (used the non Q version) and found that over the range 3.6 to 5.25 the LM3671 is much better so we would want the LM3671 1.25V version in indistrial temperature range.

    Thanks again for your help.

    Regards,

    John

     

     

  • 0 in reply to WhiteHorse
    TI__Guru 71526 points

    Hi John,

      How about TPS62003?  While there is not a fixed 1.25v OUT, there is an adjustable version, and it has better efficiency than the LM3671. 

    I don't have a response yet from the product group on the -Q1 version of the LM3671, so I'm giving other alternatives I hope will be helpful: http://www.ti.com/product/tps62003 . 

    As well, I'm guessing you need the -40C at the low end, 85C is acceptable for the high end, not 125C?  If you need the 125C, then the TPS62260-Q1 might be an option: http://www.ti.com/product/tps62261-q1 .  I sent you the Webench design, and I'm thinking the TPS62003 does not yet have a Webench model.  

     -Leonard  

     

       

     

  • 0 in reply to WhiteHorse
    TI__Guru 71526 points

    Hi John,

      Only the 1.2v -Q1 version is available now, the 1.8v version in 2013-Q3, no other versions are planned.  The way the VOUT is set is with an internal voltage divider to the FB pin, similar to what we would do with the adjustable version.  What the customer can do is use the 1.2v version, add a resistor externally between FB and GND to "trim" the voltage to 1.25v.

    Otherwise, one of the other devices will have to be used for the extended temp range.

    -Leonard

     

  • 0
    TI__Intellectual 1955 points

    John,

    LM3671 DS:

    OPERATING RATINGS

    nput Voltage Range   2.7V to 5.5V

    Recommended Load Current 0mA to 600 mA

    Junction Temperature (TJ) Range −40°C to +125°C

    Ambient Temperature (TA) Range (4) −40°C to +85°C

    Also it features an external adjustable version which one can set to any voltage within bount (infinite #).

    Please See DS TYPICAL APPLICATION CIRCUITS

    Figure 1. Typical Application Circuit

    Figure 2. Typical Application Circuit for ADJ version

    Regards,

    Kern

  • 0 in reply to Kern Wong
    Genius 4430 points

    Hi Kern,

    Good find.  The customer and I just looked at the temperature range on the website and ruled the LNM3671 out.  The data sheet temp range (−40°C to +125°C) is what the customer needed.  Thanks for pointing this out.  That answers my question. 

    Regards,

    John