TM4C129 128-TQFP Package

SourceTwo said:

can someone who has actually laid eyes on a TM4C129 in TQFP please comment?

Suspect this is Source 2's "friendly/diplomatic way" of discouraging "swags" - from those who (very sporadically) so indulge.

While this reporter can "marry" couples (while at sea) - has achieved documented cures (by the "laying on" of hands) (and solder) and has taught sea-going parrot to "swear" (several languages) - he'll maintain "radio-thread" silence in accord w/poster's directive.   (but that ain't no fun...)

cb1- said:

Suspect this is Source 2's "friendly/diplomatic way" of discouraging "swags" - from those who (very sporadically) so indulge.

 Hi CB1, my way can also be to try another way and stop project again and definitively change to a more professional way as we need to our jobs.

 The image on Mouser and Digikey too report a disclaimer "image is just for reference", on proper document from TI all tqfp layout is quoted and that is the only reference can be read by who normally read and learn by reading I think we tend lo lend alone my friend.....

 I soldered and completed a design and no thermal pad is present on TIVA part poster mentioned as from data sheet.

  Can be time when TI acquired some 100K unit sold instead of Microchip in the past and MC people previously laugh, then cryd on front of ready production one month later, nor sold processor nor other stuff,  start have some more 1K-million unit sold from TI competitor and leave them just serve one chip unit maker....

 If TI wish 1M Freescale/Altera used instead of TIVA probably can learn more from this useless forum if this touch them.

Ciao Roberto,

Having thought bit more - I'd bet that photo was of "QFN" package - not "QFP!"  Yet - as you say Roberto - MCU manual and "package section" therein - while making for dull reading - (usually) provides needed detail...

QFP usually have sufficient number and size/length of exiting "pin-leads" - to carry device's heat to a properly designed pcb.  QFN (usually) are smaller - and without those pin lead-frames - thus require that strategic (and brutal) "heat transfer pad" to keep device safe.  (sometimes - that pad ties to device ground - but user must employ caution - that's not universally true...)

@ Aquino,

As you actually have poster's device - and were quick/kind enough to respond - you provided "exactly" what he sought.  My response - based upon "indirect" experience (outlined above) did not carry as much weight as original poster (demands.)   (like that's going to stop me...)  "Laid hands on" was a, "play on words" to poster's (too restrictive) "laid eyes on."

@ Source 2,

While I've (never) seen/examined a "Unicorn" - I sure as heck "know" what one looks like.  (yet I'd avoid "up close" search for any (underside) pads or such...)

Hello,

Thank you to all who commented above.

As a clarification, there is indeed a version of the TQFP package/family that  provides a thermal pad on the bottom - sometimes known as a HTQFP.  I am vey familiar with the TI datasheet, and it unambiguously represents a standard TQFP.  In addition, I have spotted misrepresentative images on DigiKey's web site before, and have noted their disclaimer.  Nonetheless, I expect you will agree that it gives pause to see the HTQFP image on the site and begin second guessing the datasheet.  This is in light of our having >100 PCBs in the fabrication pipeline.

For the record, another manufacturer of Cortex-M4 devices uses just such a thermally-enhanced TQFP.  I feel justified in seeking the convenient and expeditious confirmation made possible by a forum such as this, and Aquino responded quickly to arrest my concerns.

Keep up the good work - and Happy New Year!

Regards,

Dave

@ Da Source,

Wondrous detail you've (just) provided.  Our small group - while reasonably active (here/elsewhere) - has yet to encounter QFP "burdened" w/bottom thermal pad.

That said - does not your finding raise concern - possibly sound an alarm bell?  My thought - as the vendor "signals" that (some) devices (may) require that thermal (heat escape) pad - how then do those devices differ from the (heat-pad free) version you've chosen?   Should that not warrant your consideration?

Perhaps the thermally augmented device runs @ higher System Clock - or has more pins, peripherals - or some other "heat-generating" baggage.  Now - if that thermally enhanced device appears in the same physical size, and peripheral mix, and System Clock speeds as it's less enhanced brother (i.e. your device) I'd have grave concern!   Might it be - that the thermally enhanced device - operates over a broader temperature range?   (such would allay many/most of my fears)

Your relaxed weekend (wondrous goal, that) may require bit more digging prior to launch...

SourceTwo said:

there could be no thermal concerns

One hopes - yet (again) if the specs & package & Peripheral inventory are identical - why issue an, "HTQFP" package? 

Heat has long been "the enemy" - vendor's creation of a more capable "heat transfer" method signals their recognition of a (potential) issue.  If you've (really) not fully compared specs & peripheral outfitting of (HTQFP vs. TQFP) such may prove unwise...  (despite another's "wishful" thinking...)

And - you've "Verified" the "hands-on" post report stating, "NO heat transfer pad was found/exists."   Yet - your own (new) "facts in evidence" state that indeed - an HTQFP package - very much does exist.   One natually wonders - just what has been verified?

SourceTwo said:

The two most recent instances of the HTQFP I've noticed were for a stepper controller/driver

 Hi Dave, yes I confirm thermal package exists but not on .3mm lead due it move on soldering phase, I confirm you again exact part is a simple package I own from early 2013 when I got samples.

 Again I can confirm running @120MHZ  it is little warmed but I use for now a 1294 instead @70MHz (network issue and safety margin) samples was not ready at design time.

 About competitor part as CB1 with his multi-vendor experience said it is better take some caution before to adopt maybe some error exists.

 More than chip carrier it is better take some information from distribution channel stock, see from here the selection of tqfp128 and just only tm4c1294ncpdt has large availability, this is not so important on first check your dealer close to you, 1290 has better price target, the one I choosed is available in large qty now.

http://www.ti.com/lsds/ti/microcontrollers_16-bit_32-bit/c2000_performance/control_automation/tm4c12x/products.page#p2955=128TQFP

TM4C129ENPDT doesn't exists.

http://www.ebv.com/search/?keyword=tm4c129&category=0&L=

 Stock from distributor

http://www.digikey.com/product-search/en?FV=fff40027%2Cfff800cd%2C40341d&k=tm4c129&mnonly=0&newproducts=0&ColumnSort=-1000009&page=1&stock=1&pbfree=0&rohs=0&quantity=&ptm=0&fid=0&pageSize=25

 About images, this is exact as is but not a photo:

http://www.digikey.com/product-detail/en/LMR24220TL%2FNOPB/LMR24220TL%2FNOPBTR-ND/2762081

 Here an image similar but appropriate to case you mention not needed for thermal issue but exposed:

http://www.digikey.com/product-detail/en/5M160ZE64I5N/544-2970-ND/2660745

 This seems a photographic reproduction of real device and you accepted as real

 http://www.digikey.com/product-detail/en/TM4C1290NCPDTT3/296-37941-ND/4915510

 Here the text under the image scared you:

Image shown is a representation only. Exact specifications should be obtained from the product data sheet.

Roberto congratulations won an award. LOLOLOL

An informative only to complement. observations:

I have 100 pieces of TM4C129ENCPDTI3, and no bottom has large thermal pad, Sorry Dave, did not put the "C". We have to be precise! ;-)

Show, lost time with all the conclusions ...!

Best Regards.
Aquino

May one here attempt to, "Put this dead/dying horse" out of its misery?

Da Source (invited) "eyes on" only response - and poster Aquino supplied just that.  Yet - perhaps - went "bit too far" when suggesting, "thermal pads do not exist - that part, that family."   Both Da Source and now Roberto prove otherwise. 

Appears that "eyes or hands on" has (some) yet not (perfect) value.   Thorough investigation of all available data sources - and vendor Sales/Tech staff - likely proves superior to "eyes/hands on."  

Yet another lesson learned, "be careful when framing your request."   Imperfect request is most likely to yield imperfect response - no matter, "how well responders' intend..."

OK:

http://www.ti.com/lit/an/spma056/spma056.pdf           (page 19,20,21,22)

http://www.ti.com/lit/ds/symlink/tm4c1294ncpdt.pdf        (page 1887)

http://www.ti.com/lit/df/spmr239/spmr239.pdf

None of them exists "large bottom thermal pad!".

Best Regards
Aquino

Roberto, is forgiven, I have nothing against you. Simply have to also respect the responses of others. This is an open forum to discuss issues about TIVA. Both children and adults as the gifted can comment about of the issues. If you do not like, patience.

If I offended you, sorry. It was never my intention.

You are wasting your precious time with me, I am sorry.

The forum is open to all!

Best Regards.
Aquino