View mb81c4256-10psz datasheet:

MB81C4256-10PSZ IL00 ********** ( )-BIT DYNAMIC RAM C-MOS 1M 262, 144 X 4 -SIDE VIEW- VDD (+5V) GND NC *10 1 2 3 4 5 6 7 8 9 11 12 13 14 15 16 17 18 19 20 OE CAS D3 D4 D1 D2 WE RAS A0 A1 A2 A3 A4 A5 A6 A7 A8 *NOTE ; PIN 10 OF MSM514256B/BL SERIES IS NO LEAD. 11 A0 12 A1 13 A0 - A8 ; ADDRESS INPUT A2 CAS ; COLUMN ADDRESS STROBE 14 A3 D1 - D4 ; DATA INPUTS/OUTPUTS 16 6 A4 D1 OE ; OUTPUT ENABLE 17 7 A5 D2 RAS ; ROW ADDRESS STROBE 18 3 WE ; WRITE ENABLE A6 D3 19 4 A7 D4 20 A8 CAS RAS OE WE 2 9 1 8 8 WE 2 CAS 9 RAS REF. CONT. ADDRESS RAS CLOCK CAS CLOCK WRITE CLK COUNTER GEN. GEN. GEN. 9 DATA COLUMN 9 44 IN DECODER 6, 7, 1, 3 BUF. SENSE 4 4 D1 - D4 AMP. 11 - 14, 16 - 20 99 DATA A0 - A8 512 X 4 4 OUT 4