Good idea to use less power integrated circuit chips and allow to use 1.5A regulator. But my past experience taught me to limit the current at 1A and use 1.5A regulator. This allow "safe range" in case if current may unexpected raise near or over 1.5A will lead failure and may damage the board components. That is why, I play safe to use expensive 3A regulator as considered as "Heavy Duty".
Hmm, I guess it may better idea for future boards to allow builder to select either TO-3 or TO-220 on same board. The heat sink for TO-220 will cover TO-3 on the board. It is very important to use fish paper between PCB and TO-220 heat sink to avoid short circuit. The fibroid fish paper electrical insulation available from GC Electronics #560, Newark sells this for $9.98 each and perhaps other vendors may provide material for less cost.
http://www.newark.com/gc-electronics/560/fibroid-fish-paper-electrical-insulation/dp/94F4073
or use TO-220 heat sinks insulation bushing and film, check at:
http://www.ebay.com/itm/10-Units-Black-Heat-Sinks-Insulation-Bushing-And-Film-TO-220-/370642657866?pt=LH_DefaultDomain_0&hash=item564c06224a
I use fish paper often on my past projects as learned about it since old days with Heathkit. They use it a lot and never have any problem. :-)
On Tuesday, November 12, 2013 3:30:46 PM UTC-5, Vince Mulhollon wrote:
On Tuesday, November 12, 2013 1:21:05 PM UTC-6, monahanz wrote:
Good point Steven, for new boards I will use LM323T’s. Mouser has them at $1.56 each!
Mouser has them at 4 cents less than Digikey, but Mouser is out of stock until December while Digikey has over a thousand ready to ship today.
Some power measurements are in order; folks who use HCT vs ALS vs LS might be able to save some dough and use the 1.5 amp TO-220 same pinout that only cost fifty cents or so.