a 255-Ball Chip Scale Package Ball Grid Array [CS_PBGA] (BC-255-1) Dimensions shown in millimeters A1 CORNER INDEX AREA 17.20 17.00 SQ 16.80 BALL A1 CORNER 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 A B C D E F G H J K L M N P R T 15.00 BSC SQ 1.00 BSC TOP VIEW BOTTOM VIEW DETAIL A DETAIL A 3.50 3.00 MAX 0.25 MIN SEATING PLANE 0.70 COPLANARITY 0.60 0.20 0.50 BALL DIAMETER COMPLIANT TO JEDEC STANDARDS MS-034-AAF-1. 012006-0 0.30 MIN