Just a curiosity question About the 7805

I've noticed on almost all Arduino's or clones and verities thereof all use a LDO ps like the MC33269

Why never the DPAK type of the various 7805's?

Reliability, space, price, precision?

I think people are trying to become more energy efficient (being able to feed in about 6.5 volts instead of 8-9).

It seems to be the way everyone is swinging, but I still prefer the 7805 :).

It strikes me that there's a bit of a catch-22 if you need lots of current. The MC33269 can run off a lower input voltage so it'll drop less and make less heat, but the 7805 has a higher ceiling in terms of output current limit.

Also strikes me that the 7805 has "worse" voltage tolerances (.25v seems typical?)

It really sucks that they're not pin-compatible, because that would mean you could design a universal circuit and let the end user pick.

Reliability, space, price, precision?

I would say price. For the performance the MC33269 is a good value.
Unfortunately the pinout is different. There is also a unusual ESR
requirement that does require caps that are a little more expensive.

Another factor may be age. A lot of people are familiar with the
part. The datasheet I have is dated 2006 and is Rev 22 :wink:

(* jcl *)


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