Does the SX52 NEED a heatsink??
cbmeeks
Posts: 634
The XGS I have (which is powered by an SX52) has a heatsink. I have heard people say it really isn't needed.
I know the SX52 protoboards don't have them.
So, should I worry about it? I plan on running these things a LOT at up to 80MIPS (50, most of the time).
thanks
cbmeeks
I know the SX52 protoboards don't have them.
So, should I worry about it? I plan on running these things a LOT at up to 80MIPS (50, most of the time).
thanks
cbmeeks
Comments
Like any overclocking situation, more efficient dissipation of heat is good. If you plan to use it at 80MHz, leave it on. It's cheap insurance.
-dave
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This is not a sig. This is a duck. Quack.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"What's the difference between ignorance and apathy ?"
"I don't know, and I don't care."
·
We've seen a variety of applications with the SX at different frequencies, both from our customers and our from our own products. Above 50 MIPS the SX truly runs pretty warm-to-hot and a heat sink is necessary. At 80 MIPS it will be hot enough that you can't hold your finger on it very long. Andre' LaMothe's XGS has shown that the SX runs reliably at 75+ MIPS even though you can cook eggs on it if the heatsink were removed.
Ken Gracey
Parallax, Inc.
cbmeeks
Unless your doing color, 50 MHz should be plenty fast. I have successful ran my sx-video board at 20MHz. Of course if I add one more instruction...It dies (not enough cycles to complete the interrupt). So I have settled on 25Mhz. For color your going to want a multiple of the color burst frequency.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"What's the difference between ignorance and apathy ?"
"I don't know, and I don't care."
·
I have also created a B/W video circuit using a PIC16F84 (20 Mhz), SX28 (50Mhz), and a SX52 (80Mhz). In fact, my current video circuit uses a 4bit gray scale for 16 shades of gray.
I haven't decided how I am going to do color (vga or NTSC). I would like both but I want to master one before I move to the other. VGA is easy except for those darn timing problems I am having...lol
If I use NTSC, I am going to try and figure out how to get some external help like the xgs does. I know color can be done purely in software but I want some speed too.
So what is the compromise:
The SX will not perform the same at these elevated operating temperatures as it will at room temperature. So you must be sure to validate the performance at operating temperature extremes (hot day and 80 Mhz with no breezes). Know that your operating the chip at these elevated temperatures will increase the defect activation rate. How long your chip will last depends upon many factors related to die defects, it could be seconds or years. The higher temperature just compresses the life expectancy of your specific chip. If it was destined to last 20 years running at 50 Mhz it may only last 6 years at the elevated temperature. If it had some infant mortality issue its life of say 5 months @ 50 Mhz could become a week at 80 Mhz.
Recommendations:
Use your SX chip and relax. The cost of the SX chips and boards is not prohibitive. If you have repeated failures or damage occurs with the raw chip, use a heatsink and or impose air flow using a fan.
If you decide to throw caution to the wind, please post your findings (good or bad) on this discussion forum to help others.
JT
What I probably will do is just run the chip with no heat sink while I am developing...because it will be in an AC contolled room outisde a case and just put a heat sink on when it goes to production
I don't know if you are using SX/B for your VGA code, but the newest version allows fraction microsecond delays like "PAUSEUS 6.7" which is great for us video freaks.
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"What's the difference between ignorance and apathy ?"
"I don't know, and I don't care."
·
How accurate is the SX/B for timing?
I mean, if I code this:
at 50MIPS, does that generate 51 clocks?
I thought this was for personal use. The way your going about it sounds like the right way to go. If these are going into production you should heatsink if you want to guarantee the end user of a durable and robust product. A hotter running chip will have a shortened life and statistically this may result in higher returns. Also if you decide to use the chip alone, burns could result. Excuse the pun, but this would be uncool! A heatsink would reduce the operating temperature, and as such, the burn hazard would be greatly mitigated. If you intend on using an enclosure be sure to include vent holes/slats, preferably the ones that are aimed downward to help reduce liquid or solid contamination.
JT
Post Edited (Miner_with_a_PIC) : 7/5/2005 8:33:27 PM GMT
The "HIGH" command has alot of overhead to keep track of the pin direction.
Instead use "RC.1=1" this will translate to "SETB RC.1" which is 1 instruction. Of course you must use "OUTPUT RC.1" before using RC.1=1
Bean.
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"SX-Video·Module" Now available from Parallax for only $28.95
http://www.parallax.com/detail.asp?product_id=30012
Product web site: www.sxvm.com
"What's the difference between ignorance and apathy ?"
"I don't know, and I don't care."
·
Well, by "production", I mean getting a PCB made for me. hehehe
Seriously, I am building/designing my own computer and I want it to be as professional as possible. I will add the heatsink when it's done.
Bean:
Thanks for the tip. I honestly might just use ASM for everything. I am pretty good at it and about the only thing SX/B gives "ME" that I can't easily do in ASM is SOUND, FREQOUT, etc.
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http://www.analog.com/en/prod/0,2877,AD725,00.html
Brad
If I could just figure out how to solder the darn things!!
cbmeeks
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http://metroidclassic.com
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That looks like an SOIC chip. For soldering, have you considered an adapter? With a little bit of liquid solder flux, a magnifying lamp (circular flour with magnifying glass in center) and a resonable soldering iron, these work quite well.
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=291514
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John J. Couture
San Diego Miramar College
I have ran the SX52 protoboard WITHOUT a heatsink at 80 MIPS and it gets HOT. Too hot to hold your finger on for long. I only ran it for about 45 seconds.
I am going to back it down to about 50 MIPS and try that (until I can get a heatsink because I do want to run close to 80 MIPS)
Anyway, just an update!
cbmeeks
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
{And can the SX-Key really handle that? I would get just as hot I assume}
Actually, I have been wondering -- How exactly might I attach a heatsink to the little guy?
Americans alway want to stretch the limits. Right?
~~~~
REGARDING Soldering.
Consider the concept of 'reflux'. Actually the board is coated with a special solder paste, the componet is placed in the proper position, and then the whole think is popped into a 'toaster oven' for a few minutes. The viscosity of the paste beads the solder as it melts. The paste seems to provide both stickyness and the appropriate amount of solder [noparse][[/noparse]a very thin layer].
Digikey has the solder, but the bad news is that it is shipped refrigerated as it apparently is chemically active at room temperature. A little tube goes a long way - but it is something like $50USD plus having a courier deliver it directly to you. Hmmmm.
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G. Herzog in Taiwan
There are ready made heatsink kits for several different size ic applications, once you apply the heatsink, it is on to stay.
Try these links:
www.thermaflo.com/index.shtml?type=GoogleAdwordsSearch
www.digikey.com/scripts/dksearch/dksus.dll?Criteria?Ref=243094&Site=US&Cat=32113433
Bob N9LVU
Another way I have solder SMT parts is with solder flux purchased at RS. I swabbed some on the surface, put the IC on, and ran an iron gently across the pins. Worked great. In fact, just for grins, I tried to pry it off and couldn't without using a pry-bar (screw driver) and a lot of force.
So, I think my method is good for prototyping. Only time will tell how well it does in the future.
cbmeeks
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http://metroidclassic.com
=========
DMCA Sucks
RIAA Sucks
On the SX-Key, there is a programmable clock generator allowing for a large range of frequencies (even above 110 MHz), and I don't think it will get hot. Exceeding the clock frequencies above the specs of 50 or 75 MHz is on your own risk. It may work fine, or not.
A heat sink is definitely an additional safety measure. You should keep in mind though, that the SX packages have no specific provisions for reduced thermal resistance, as you can find it on other components, like on microprocessors for PCs. You should also apply some heat-conductive paste, or heat-conductive glue between the chip package and the heat sink to reduce the thermal resistance.
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Greetings from Germany,
G
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·1+1=10
I am quite wary of this because I am a guest in a foreign country and they might think I am CIA or something.
If you are going to try it, be sure to have it fully enclosed in a shielded box to prevent RFI. The box might keep you from collecting scrapnell too.
[noparse][[/noparse]I read a story about a guy with a defective TV being visited by the FBI, FCC, and the FAA becuase he was transmiting on the crashed airplane transponder frequency.]
In other words, Saftey First and avoid unfriendly visits.
Regarding innovative cooling.
The Peltier junction draws quite a bit of power, doesn't it?
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G. Herzog in Taiwan