Hannah Montana Star Facing Jail Time

Law enforcement sources tells TMZ ... the Burbank City Attorney has charged Musso with driving under the influence of alcohol and driving with a blood alcohol level of .08 or higher -- both misdemeanors.

If convicted on both counts, 20-year-old Musso faces a maximum of 6 months in jail and a $1,000 fine.

TMZ broke the story ... Musso was pulled over at 3:43 AM Sunday ... after he allegedly failed to slow down for cops who were directing traffic for an unrelated accident. Cops suspected he was hammered and placed him under arrest.