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LM22676: Longevity and availability of LM22676TJE-5.0/NOPB

Alex Halfin
Prodigy 70 points
Part Number: LM22676
Other Parts Discussed in Thread: LMR51430, LMQ66430, LMR33630

Hello 

Currently I am using following DC-DC:

- LM22676TJE-5.0/NOPB - for 16VDC to 12VDC 3A conversion

- LM22676TJE-5.0/NOPB - for 16VDC to 5VDC 3A conversion

- LM22678TJE-ADJ/NOPB - for 16VDC to 3.3VDC 5A conversion

For proper power up sequence I need to power up first 3.3VDC and after this 5VDC. For this I am using an enable pin of LM22676TJE-5.0/NOPB from 16VDC to 5VDC connected with resistors divider to 3.3VDC.

As these parts are relatively old I am concerned about their longevity.

If I want to use a single part number for all 3 converters what you suggest?

1. To use LM22676TJE-5.0/NOPB also for 16VDC  to 3.3VDC 3A conversion (3A is enough and I am not must 5A).

2. Or to use another DC-DC with enable pin with better longevity, availability  and etc..? If you suggest this option what part number is a recommended one?

Thank you.

Alex

  • 0
    TI__Genius 13735 points

    hi, Alex,

    Thank you for reaching out to us, looking from LM22676, you prefer a 36V 3A part, without Q-grade requirement and EN function is need. I have some new part list below 

    1,  LMR51430 for easy of use and cost effective,

    2, LMQ66430 is better performance with good EMI .

    3, LMR33630 with more pin option function. and it can support 1~4A of the same pinout for this part. 

    Elena

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello 

    I think I will take: LMR33630 device.

    This device have 2 packages HSOIC and VQFN. When I compare both packages in HSOIC Junction-to-ambient thermal resistance is lower (more effective) but from other side Junction-to-case (top) thermal resistance is higher (less effective).

    I don't have a limitation in space in this project and want to select a most appropriate IC from longevity, availability, thermal and other aspects - what package you recommend?

    When was this component released (is it new enough)?

    Thank you. 

    Alex

  • 0 in reply to Alex Halfin
    TI__Genius 13735 points

    Yes this is new product but ,around 2018 first released.

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello

    And in what package and frequency is most popular and recommended: HSOIC or VQFN?

    Thank you.

    Alex

  • 0 in reply to Alex Halfin
    TI__Genius 13735 points

    I prefer the DDA package ,that is consider from thermal and cost, also for long term and large volume .But we didn't means to say QFN is not good.  :)

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello 

    And as I understand the most popular version is with 2100Khz frequency: LMR33630CDDA?

    Thank you.

    Alex

  • 0 in reply to Alex Halfin
    TI__Genius 13735 points

    Hi, Alex,

    I list the OPN table here, higher frequency means smaller size and value in inductor, notice a good layout and thermal design is required when run under max loading @high frequency.  

    Elena

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello 

    There is a following advice on page 22 of LMR33630CDDA datasheet:

    I have a long lead (even could be more than 2 meters) between voltage source and DC-DC's.

    I am concerned about lifetime of the electrolytic capacitors that is relatively short.

    1. Do you have any other recommendations: like using different types of capacitors and etc?

    2. If I will use 3 x LMR33630 as mentioned above - you think a single high capacitance (100uF) is enough for all 3 of them?

    Thank you.

    Alex

  • 0 in reply to Alex Halfin
    TI__Genius 13735 points

    hi, Alex,

    This is much related with the system power, the electrolytic capacitors is suggest to add much like a "protection" , based the 16V DC voltage ,the ring may 2 or 3 times higher than it. That's will exceed the IC ABSMAX, 

    For other way do you consider like TVS or efuse or a diode in input side, or do you consider to use much high voltage rate Buck IC, like 60V or 100V.

    Elena

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello

    I want to have an option to regulate all DC-DC's to all needed voltages (12VDC, 5VDC and 3.3VDC) also from 24VDC nominal voltage and not only 16VDC.

    When trying to create a design with WEBENCH Power designer based on LMR33630CDDA 24VDC -> 12VDC, 3A with ambient temperature of 45 deg Celsius, the design fails with message that maximum junction temperature exceeded.

    Now I think what is better to leave my current design based on LM22676TJE-5.0/NOPB for 12VDC regulation only and to use LMR33630CDDA only for 5VDC and 3.3VD regulation or to select another TI component (not LMR33630CDDA) for all 3 voltages that can work from nominal VIN of 16VDC and 24VDC with higher ambient temperature?

    1. Can you suggest another component?

    2. As LM22676TJE-5.0/NOPB quite old component - do you know when it will be end of life?

    Thank you.

    Alex

  • 0 in reply to Alex Halfin
    TI__Genius 13735 points

    hi, Alex

    Could you accept frequency like 400K, A version or B version for a better thermal @3A.

    LM22676 can still be order now, I am not sure the end time, but suggest to move to new product when new design, 

    Elena

  • 0 in reply to Elena Gao
    Prodigy 70 points

    Hello

    Yes, I will use a B version - LMR33630BDDA.

    And also use electrolytic capacitor with 10000 HRS @ 105°C rating (that should work for > 15 years in our environmental conditions).

    Thank you.

    Alex