A U.S. judge slashed the penalty levied by a jury against a Boston Ph.D. student found guilty in 2009 of illegally downloading and sharing songs published by some of the world's biggest recording companies.

Judge Nancy Gertner of the U.S. District Court in Boston ruled on Friday that it would violate the constitutional rights of defendant Joel Tenenbaum to require him to pay the full $675,000 in penalties a jury awarded to the five record companies that sued him, saying the sum was excessive.

Instead she ordered him to pay $67,500 in damages to the companies -- Sony BMG Music Entertainment, Warner Bros. Records Inc, Atlantic Recording Corp Arista Records LLC and UMG Recordings Inc.

This award is far greater than necessary to serve the government's legitimate interests in compensating copyright owners and deterring infringement, she said in a 62-page decision.

Tenenbaum admitted he illegally downloaded and shared hundreds of songs from 1999 to at least 2007.

(Reporting by Jim Finkle; editing by Andre Grenon)