Why

[eo32]

In virtualy every design ive seen for portable snes' people have replaced the 7805 voltage regulator with a LF50CV and after checking the tech specs for them there seems to be very little difference (besides a slightly lower quiescent current draw) between them, could someone please enlighten me?

Also, has anyone got any estimates for play time on 8 AA's using the original 7805? (assuming good 2000mAh batteries are used)

Many Thanks
Eo

[SNESguy]

They replace the SNES's regulator because it is finicky, and often won't power the screen or won't run if they are hacked.

Switching regulators are best because they need no heatsink.

Ben gave that explanation in his book.

[electromaster64]

It has nothing to do with hacked screens, sorry. The reason the 7805 is replaced is because the LF50CV is a Low Drop Out (LDO) voltage regulator and continues to put out the power needed to power the SNES even when the power supplied by the batteries is extremely low. The 7805 is not LDO and will quit working as the voltage drops in your batteries this results in little or no play time with the 7805 (this also waste your batteries). The LF50CV allows the SNES to run on 4AA's and run longer than the 7805. See my SNES how-to on www.doomportables.org for more info on replacing the 7805.