DTTX Died From Desert Heat

Rapper DTTX was killed by the blazing Las Vegas sun ... TMZ has learned.

Bobby Ramirez, best known as DTTX from A Lighter Shade of Brown -- died in July from heatstroke, with exposure as a contributing factor ... according to the Clark County Coroner, which also ruled the death accidental.

As we reported, Ramirez was on life support for 11 days after he was found laid out on the Vegas strip. His body temperature was 107 degrees.