297-Ball Plastic Ball Grid Array [PBGA] (B-297) Dimensions shown in millimeters a 27.20 27.00 SQ 26.80 A1 CORNER INDEX AREA 26 24 22 20 18 16 14 12 10 8 6 4 2 9 3 5 25 23 21 19 17 15 13 11 7 1 A B C D E F G H J K L M N P R T U V W Y AA AB AC AD AE AF A1 BALL PAD CORNER BOTTOM VIEW 24.20 24.00 SQ 23.80 TOP VIEW 25.00 BSC SQ 1.00 BSC 2.43 2.23 2.03 8.00 BSC SQ DETAIL A 1.22 1.17 1.12 DETAIL A 0.61 0.56 0.51 0.50 NOM 0.40 MIN 0.70 0.60 0.50 BALL DIAMETER COMPLIANT TO JEDEC STANDARDS MS-034-AAL-1 COPLANARITY 0.20 MAX SEATING PLANE