Lane Kiffin -- Don't Compare USC to Penn State

USC head football coach Lane Kiffin knows what it's like to run a program that's been hit with major NCAA sanctions ... but the leader of Troy tells TMZ ya just can't compare SC to Penn State.

Lane -- along with his star QB Matt Barkley -- was leaving Pac-12 Media Day at the Gibson Amphitheater at Universal CityWalk yesterday when we asked how he felt about the Penn State punishment.

Here's why Lane's opinion matters ... the SC football team was hit with a 2-YEAR postseason ban in 2010 ... after the NCAA uncovered violations surrounding illegal compensation to USC running back Reggie Bush.

SC was also stripped of its 2004 national championship victory, vacated all wins from the 2005 season and lost several scholarships.

The Penn State football program -- which covered up a CHILD RAPE SCANDAL FOR A DECADE -- was only banned from postseason play for 4 YEARS ... plus, a $60 million fine, scholarship reductions ... and of course, the Nittany Lions had to vacate 111 wins.

"The situations are different," Kiffin said ... noting, "It's impossible to compare the penalties in the situations."