2008.03.17, 03:17 PM
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#31
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Registered User
Join Date: Mar 2004
Location: Northwest
Posts: 550
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Edit: woops, too late and too long
Quote:
Originally Posted by Felix2010
...I did a search for the 8958A Fets and there were three versions listed. One was listed as "obsolete", but the other two were In-Stock: One FET was listed as manufacturer part#512-FDS8958A_Q and the other was listed as manufacturer part#512-FDS8958A . The prices for these FETs are different: The 512-FDS8958A_Q version costs $1.57 per Fet; The 512-FDS8958A version costs $3.03 per Fet. I am thinking about ordering a few of these 8958A Fets to try when I order the 8858CZ Fets - Could you tell me which one is the "correct" 8958A Fet that I should purchase? ...
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They are both the same mosfet, the only difference is that the $3.03 version is guaranteed meet the following criteria:
RoHS (EU Directive 2002/95/EC) the maximum concentration values of the restricted substances by weight in any homogenous materials are:
• Cadmium/Cadmium Compounds 0.01%
• Hexavalent Chromium/ Hexavalent Chromium Compounds 0.10%
• Lead/Lead Compounds 0.10%
• Mercury/Mercury Compounds 0.10%
• Polybrominated Biphenyls (PBBs) 0.10%
• Polybrominated Biphenylethers (PBDEs)0.10%
While the $1.57 may still not contain any of the above listed materials in the prohibited quantities but has no guarantee.
I'd go for the $1.57.
Quote:
Originally Posted by Felix2010
LBRC & pinoyboy - Are there any other Fets that you recommend I should look at buying to try on Mini-Zs while I'm here placing an order?
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If you are experimenting with different FETs IMO you need a bench mark and that’s the Vishay SI4562DY since it set the standard, but unfortunately is becoming hard to find.
Then there’s the IRF 7389 it’s the odd FET, gets a bum wrap because the peeps want max current and lowest resistance on a data sheet to tell the whole story.
Haven’t’ tried any but the Rohm SP8M4 looks interesting.
BTW
Awhile back a put a 1x1 set of the 8858’s in an old MR-01 along with an Atomic T2 and 6 tooth pinion, and left it by the track for anyone to drive since I haven’t had much time to play lately, the good news is that surprisingly the FETs are still in good shape, the bad is that no servo saver and a T2 on a relatively small track for anyone to drive…ouch not sure how much use it got before the servo baught the farm.
__________________
Jungle Outlaw Micro Racing
If the track is wet, then the tent is leaking.
Last edited by LBRC; 2008.03.17 at 03:32 PM.
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2008.03.18, 06:27 AM
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#32
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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Quote:
Originally Posted by kja812
I checked mouser's site for you.
The _Q parts are non-lead free while the other parts are newer lead-free production parts. Save the couple bucks and order the _Q parts.
Looks like they have stock of the ever popular Vishay SI4562DY.
They also have stock of a few other Fairchild parts that aren't quite as good as the two you're looking at: FDS4897/FDS8960/FDS8962/FDS4885.
Hope this helps.
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kja812 - Thank you, this info helps a lot. Out of the four other Fairchid parts you listed, the one that I know a good friend of mine had good experience with was the FDS8962. I will probably grab some of these. I have some Si4562DY's hanging around, but they're good to have - I'll check them out on mouser. Thanks again
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2008.03.18, 06:57 AM
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#33
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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Quote:
Originally Posted by LBRC
Edit: woops, too late and too long
They are both the same mosfet, the only difference is that the $3.03 version is guaranteed meet the following criteria:
RoHS (EU Directive 2002/95/EC) the maximum concentration values of the restricted substances by weight in any homogenous materials are:
• Cadmium/Cadmium Compounds 0.01%
• Hexavalent Chromium/ Hexavalent Chromium Compounds 0.10%
• Lead/Lead Compounds 0.10%
• Mercury/Mercury Compounds 0.10%
• Polybrominated Biphenyls (PBBs) 0.10%
• Polybrominated Biphenylethers (PBDEs)0.10%
While the $1.57 may still not contain any of the above listed materials in the prohibited quantities but has no guarantee.
I'd go for the $1.57.
If you are experimenting with different FETs IMO you need a bench mark and that’s the Vishay SI4562DY since it set the standard, but unfortunately is becoming hard to find.
Then there’s the IRF 7389 it’s the odd FET, gets a bum wrap because the peeps want max current and lowest resistance on a data sheet to tell the whole story.
Haven’t’ tried any but the Rohm SP8M4 looks interesting.
BTW
Awhile back a put a 1x1 set of the 8858’s in an old MR-01 along with an Atomic T2 and 6 tooth pinion, and left it by the track for anyone to drive since I haven’t had much time to play lately, the good news is that surprisingly the FETs are still in good shape, the bad is that no servo saver and a T2 on a relatively small track for anyone to drive…ouch not sure how much use it got before the servo baught the farm.
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LBRC - Excellent write-up, as always. I appreciate the detail you go into, I am a believer you can never have too much good info.
I had a 2x2 4562 stack put on an AD-PCB for me by a good friend who is a soldering master... The boards come back to me looking like they came from the factory made especially for me. I liked the 4562's a lot, no problems/negatives whatsoever IMO. I just recently had this same friend replace the 2x2 4562 stack with a 2x3 SP8M4 stack on the AD-PCB, and my initial testing has been excellent. For a while now I have been trying different hand pattern-wound motors made by Top Secret Motor's proprietor Flashsp-2 - (Just a lil' TSM plug - Really, really good stuff ). Sometimes the motors I run go beyond the Anima/Chili/T2 current flow and I upgraded so I could handle basically any motor I want in my AD-MA010.
But an FET-expert I am not, so all the info you provide is very much appreciated. I read the beginning of this thread about your 8858-Fetted MR-01 with the T2, and now that you've mentioned it still is up and running, the 8858CZ's I will have to try. I like how you said the 8858CZ's have a snappy-but-linear throttle feel also.
The Vishay 4562's I should grab since you wrote they are becoming harder to find.
I have not tried the IRF 7389 because of the popularity of the 4562. I haven't been in the Mini-Z arena for that long and I never investigated into the 7389. With the other Fets like the 8858CZ I am looking at and trying, I don't know if I'll have time for the 7389 - Maybe if they make a comeback .
So many Fets, so little time...
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2008.03.18, 08:25 AM
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#34
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motor guru
Join Date: May 2006
Location: In front of you...
Posts: 487
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Quote:
Originally Posted by Felix2010
I had a 2x2 4562 stack put on an AD-PCB for me by a good friend who is a soldering master... The boards come back to me looking like they came from the factory made especially for me. ... For a while now I have been trying different hand pattern-wound motors made by Top Secret Motor's proprietor Flashsp-2 - (Just a lil' TSM plug - Really, really good stuff ).
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Aww thanks bro
I haven't tried the 8858, but I did try the 8962 (2x2) for bit, as well as running stacked 3010s. The 8962 were actually quite good, the throttle was pretty linear, which is my primary concern when upgrading boards. I think the general consensus on the 3010 is great in terms of driveability, so I won't beat that horse anymore. I currently have a 2x3 SP8M4 on my AD mr02, and I love them. The throttle feel is excellent, and the power is very broad, no matter where you get on it, the car has go-juice. Even with the 2x3 it isn't switchy feeling at all, which was a big concern with changing from the 2x2 3010 of the AD. I would really like to see someone review both the 8858 and the SP8M4 back-to-back, I think that would be very interesting to see.
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2008.03.18, 10:13 AM
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#35
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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Quote:
Originally Posted by Flashsp-2
Aww thanks bro
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You're welcome.
Quote:
...I would really like to see someone review both the 8858 and the SP8M4 back-to-back, I think that would be very interesting to see.
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Sounds like a nice future project, maybe?
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2008.05.25, 10:20 PM
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#36
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Registered User
Join Date: Jan 2007
Posts: 365
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LBRC,
Thanks for the writeups, and just like to share with you my findings on these fets:
I have recently stacked 2x2 forward, 2x2 backward FDS8858CZ fets (total of 8) to my ASF 2.4G for testing. But the result is rather mysterious. The car will have a slight delay of less than a sec, when under acceleration, then it will just 'shoot off'.
Original plan is simply to have a 2x2 forward and 2x1 for backwards. But the car is behaving as said, and I wonder whether the imbalance of fet numbers is the cause. But even adding two extra to backward, the same problem persist.
Local experts, though not familiar with this fet, has told me that sometimes a fet will behave differently during acceleration/top speed/deceleration, and what looks good on paper doesn't always translate to real-life application. (which I think is genuinely true).
Have you observed any performance suffering after heavy usage of these fets? And any side effect of stacking them more than 3?
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2008.05.25, 11:47 PM
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#37
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EMUracing
Join Date: Oct 2004
Location: NYC
Posts: 7,417
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Have you tried a single layer on the forward and reverse (4 fets total)?
__________________
EMUracing
Micro RC Syndicate /DG Designs /GSR /Reflex Racing /Fast By Faqish /MurderTown Racing
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2008.05.26, 09:51 AM
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#38
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Registered User
Join Date: Mar 2008
Posts: 184
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Quote:
Originally Posted by Aurora
LBRC,
Thanks for the writeups, and just like to share with you my findings on these fets:
I have recently stacked 2x2 forward, 2x2 backward FDS8858CZ fets (total of 8) to my ASF 2.4G for testing. But the result is rather mysterious. The car will have a slight delay of less than a sec, when under acceleration, then it will just 'shoot off'.
Original plan is simply to have a 2x2 forward and 2x1 for backwards. But the car is behaving as said, and I wonder whether the imbalance of fet numbers is the cause. But even adding two extra to backward, the same problem persist.
Local experts, though not familiar with this fet, has told me that sometimes a fet will behave differently during acceleration/top speed/deceleration, and what looks good on paper doesn't always translate to real-life application. (which I think is genuinely true).
Have you observed any performance suffering after heavy usage of these fets? And any side effect of stacking them more than 3?
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Do as Emu suggested, as I m having no delay problem with mine in two of my ASF cars fitted with 8858CZ.
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2008.11.04, 03:04 PM
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#39
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hilldebrandt's hobby
Join Date: Dec 2006
Location: Reading, PA
Posts: 316
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Quote:
Originally Posted by pinoyboy
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I just looked at the Mouser site. None available, they are on backorder :
Quote:
Mouser Part #: 512-FDS8858CZ
Mfr.'s Part #: FDS8858CZ
Description: MOSFETs 30V Dual N & P-Ch PowerTrench MOSFET
Mouser Product Availability
No Stock
4,866 On Order
Estimated Ship Date
2,366 12/2/2008
2,500 12/22/2008
Factory Lead Time
11 Weeks
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2008.11.06, 10:01 PM
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#40
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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I was on mouser's website the other day, I did a search for 4562's - They're out-of-stock, but mouser listed 4511 as a possible replacement. There's an old thread from 2003 or something where someone aksed about 4511's, but no one replied.
Any FET guys have any thoughts on Vishay Si4511DY FETs?
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2008.11.11, 01:09 AM
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#41
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leo
Join Date: Apr 2006
Location: California
Posts: 70
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I have a question for the MR02 ASF. Since the 8858 and 4562 are both sold out ... I just wonder if the 8962 mentioned by Flashsp is a good temporary replacement?
Thanks.
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2008.11.11, 01:20 AM
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#42
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Registered User
Join Date: Dec 2006
Location: Southern NH
Posts: 987
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Flash knows his stuff, and I know he said the 8962 fets performed well for him. You can trust his opinion. I have heard the 8962's are similar in spec to the 4562's; I believe Flash verified this, he runs some hot motors sometimes (He winds his own custom motors, excellent stuff - Look up "Top Secret Motors").
If you find them, a better Fet still would be the SP8M4 by Rohm. They are for sale at a few places, try googling them. Flash and I both agree that the SP8M4 Fets are among the best Fets out right now. Also, I believe the 8858's can be found in-stock at Reflex Racing. The 8858's and SP8M4 Fets are considered very close in performance, so either would be a solid choice.
Hope this helps
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2008.11.11, 02:21 AM
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#43
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leo
Join Date: Apr 2006
Location: California
Posts: 70
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Thanks Felix. Perfect timing ... I just finished reading about the 8962 FETs thread by Flash, CT and a few others ... very interesting. Seems like 8962 is better than 3010 (in some people's opinion) and not as great as 8858 and 4562 ... thanks again
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2008.11.27, 06:28 PM
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#44
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hilldebrandt's hobby
Join Date: Dec 2006
Location: Reading, PA
Posts: 316
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2008.11.29, 01:00 PM
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#45
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The Galliant Dude
Join Date: Mar 2008
Location: Northern VA
Posts: 920
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Quote:
Originally Posted by hilldebrandt
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True, I ordered some last week. Now my car has 8858 FETs on it!
__________________
In need of a FET upgrade? PM me!
Concerned about sending off your precious Mini-Z? Don't be!
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