Author Topic: In need to replace a JRC or STMicro 317 Voltage Regulator. Which brand is best?  (Read 459 times)

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Offline zdelarosa00

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Which brand is best? In my knowledge, the big names that make the part are JRC, TI and STMicroelectronics.

I don't know with facts, but my personal ranking in terms of quality/performance(?) would be:
1.-JRC
2.-Texas Instruments
3.-STMicroelectronics

In terms of brand name, reputation, quality, known facts, numbers, performance of the parts, scope of the usual equipment that has them (demands of the application). But I really don't know what can change from brand to brand talking about exactly the same part, apart from volume and packaging plastic.

I really don't see JRC around much though. So maybe I'm biased by popularity.
Space landfill waste consultants say: "If you think you can or if you think you can't you're right" - Always on my way to be a better electronic wizard
 

Online blueskull

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Who cares? It's a jellybean part, so I'll go with a random one that Arrow has for cheapest this day, and I chose Arrow only for free shipping.
 

Offline floobydust

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I find a difference between brands, some makes of LM317 and 78xx are very noisy. Fairchild is shit, LT the best but very expensive.
If it's a noise critical application, like audio or metrology, measure it with a scope and be prepared for huge differences in quality.


 

Online blueskull

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LT the best but very expensive.

Then why not a cheap OPAMP and a pass element? With SMT parts, you can get smaller, cheaper and higher performance solution than using a good LM317.

I've been doing designs based on common collector direct drive designs and common emitter plus common base level shifter designs for many space constrained audio applications, and my solutions constantly beat so called high PSRR, low noise LDOs at 1/4 the cost and 1/4 the space (using advanced packages, compared with TSSOP), just at the cost of 50x higher quiescent current (5mA vs 100uA, which doesn't matter for audio, since the load, audio OPAMP supply and bias current, is quite higher).
 

Offline floobydust

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Some 1-lot Digikey $USD prices:
LT317AT(LT) $4.85
LM317BT (ST) $0.64 "single gauge" thin tab TO-220, absolute garbage
LM317T-DG (ST) $0.64 "double gauge"
LM317T (On-Semi) $0.71 "single gauge" thin tab TO-220, absolute garbage

The limitation is a 3-pin package can't have a bypass cap across the reference. But these IC's spoiled us they are so convenient.

The low noise Super Regulators from Walt Jung's work uses low noise op-amps AD825, AD848, AD797 etc. - all expensive.
I haven't tried using a cheapo NE5534 or similar with discrete pass transistor.
« Last Edit: October 13, 2019, 10:22:46 pm by floobydust »
 

Offline wraper

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LM317T (On-Semi) $0.71 "single gauge" thin tab TO-220, absolute garbage
Performance wise it does not matter. And it's not ON semi only who does this. ST does exactly the same thing. Though you probably should avoid mounting it with a screw and use spring clip instead.
 

Offline floobydust

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There's a thermal performance hit - try it. You won't find thermal data on this cornball package it's that bad.
Isn't it strange that the single gauge tab saves 55% on copper but isn't used on anything else but these voltage reg IC's LM317, 78xx. No thin tab DPAK or D2PAK out there. Hmmm.
I find the thin tab warps if you aren't very careful with torque tightening the screw. Single gauge it's just garbage all round and the rants on EDN concur.
 

Offline wraper

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There's a thermal performance hit - try it. You won't find thermal data on this cornball package it's that bad.
Nope, single gauge has the same thermal resistance as usual TO-220 and they are not distinguished in datasheets separately. Also Vreg such as 78xx and LM317 have too low maximum power dissipation for it to matter.
Quote
No thin tab DPAK or D2PAK out there.
DPAK is already about as thin as single gauge TO-220. Also SMD packages use less metal than TO-220 to begin with. As of D2PAK, there is single gauge.
https://www.onsemi.com/pub/Collateral/936-03.PDF
Quote
6. SINGLE GAUGE DESIGN WILL BE SHIPPED AFTER FPCN EXPIRATION IN OCTOBER 2011.
Also tab and center lead is a single piece of metal, side leads are too while in leadframe. In single gauge package they have the same thickness which certainly makes leadframe production easier and cheaper besides simply saving metal.

« Last Edit: October 13, 2019, 10:59:19 pm by wraper »
 

Offline floobydust

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The thermal research is purely academic FEA sims, some using a laughable 2W power. I'll remain a skeptic. https://nazrulanuar.files.wordpress.com/2008/11/b26_s0060p171-1751.pdf

"... Reducing the copper heatsink thickness to form a single gauge leadframe, a thinner version of the dual gauge leadframe, was perceived to present various electrical, thermal and reliability failure mode and mechanisms, specifically die cracking. This study presents an in-depth simulation and analysis to determine whether the thinner heatsink leadframe version is capable of achieving the defined customer product requirements on their electrical, thermal and reliability performances in a DPAK package."

" Results revealed that the safest leadframe thickness range is within 0.5 - 1.0mm. The original diepad thickness falls within the safe range. Selecting the 0.5mm as the new diepad thickness for the single gauge leadframe design was as straightforward as referring from the leads thickness of the original dual gauge design. Assembly, ambient electrical, and reliability testing were carried out for the carrier devices (non-auto and automotive types) in DPAK production line. Zero-hour electrical and reliability test results revealed that products satisfied all test specification requirements for both automotive and non-automotive devices."
https://ieeexplore.ieee.org/document/7365171

If the thickness limit is only about die cracking, no mention of thermals- they might have forgotten higher power dissipation >20W?

For TO-220 single gauge, I find the thin tab warps and doesn't contact a heatsink well, becasue of the bolt shoulder/insulator bushing contact area. This is why I hate the sneaky cheap package.

I think JEDEC should have issued a new package part number, they did for all the old parts such as TO-3, TO-92 creating more chaos when it was totally unnecessary.
 


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