Eldritch Burst (3.5e Alternate Class Feature)
From D&D Wiki
 Eldritch Burst
Your Eldritch Blast changes to a burst of power.
Replaces: Eldritch Blast
Benefit: Your Eldritch Blast changes to a burst with a radius of 10 feet at first level, 20 feet at third level, 25 feet at fifth level, 30 feet at seventh level, 40 feet at ninth level, 45 feet at eleventh level, 50 feet at thirteenth, and 60 feet at fifteenth level. The damage stays the same.
Penalty: Also, the burst gains Reflex save to halve the damage. (6d6=3d6) The Reflex is equal to 10+1/2 Warlock level+Cahrisma modifier.