Re: TI-H: SPinTerface 82 & 7805/78L05 regulators
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Re: TI-H: SPinTerface 82 & 7805/78L05 regulators
Richard Piotter wrote:
> the SPinTerface yourself, make sure to use the 78L05, not the 7805 from
> Radio Shack. You can use either one, but if you intend to build the
> speaker cart or a cart with sensitive circuits that require 5v+ exactly,
> I would go with the 78L05. It has been pointed out to me that the 7805
> has a higher dropout voltage, so if your batteries are low, you may not
> get the full 5v power supply, only 4.4 or so. It works with most stuff,
> but I am going to bulk order the 78L05 which works better and is smaller
> and uses less power. I will use those from now on in my instalations.
> I'm ordering them tommorow.
No! I have not consulted the 78L05 datasheet, however I think it is
safe to assume that the 78L05 has the same drop out as its bigger TO-220
7805 cousin. The regulator will be smaller, however the dropout will
probably
be the same and you will run into the same problems!
I would take a look at National's site... I ordered TO-263 versions of
a regulator that would work perfectly in the SPinTerface (The TO-92
versions, which are what you will want, were not availible as samples)
It has an extremely low dropout and can supply the same amount of
current as a 78L05 or non-heatsinked 7805.
So, do NOT order the 78L05. I have a few on hand and I will test them
out later... however, I think you will have the EXACT same problems
you had with the 7805 with the smaller 78L05. Since you need to
mail order them anyway, check out one of the newer, more "tolerant"
NatSemi parts (LM2931 I believe was the part number... its a 3 pin
low dropout TO-92 package regulator which should be a dropin replacement
for the 78L05)
Good luck,
Bryan Rittmeyer
bryanr@flash.net
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