View mb81c4256a-80pj datasheet:

MB81C4256A-80PJ IL08 ********** C-MOS 1M (262,144x4)-BIT DYNAMIC RAM - TOP VIEW - 9 DQ1 1 GND 26 A0 10 A1 11 1 DQ2 2 25 DQ4 A2 DQ1 12 2 A3 DQ2 14 24 WE 3 24 DQ3 A4 DQ3 15 25 A5 DQ4 16 RAS 4 23 CAS A6 17 A7 18 5 NC 22 OE A8 4 23 3 22 A0 9 18 A8 A0-8 ; ADDRESS INPUTS CAS ; COLUMN ADDRESS STROBE A1 10 17 A7 DQ1-4 ; DATA INPUTS/OUTPUTS OE ; OUTPUT ENABLE A2 11 16 A6 RAS ; ROW ADDRESS STROBE WE ; WRITE ENABLE A3 12 15 A5 13 VDD (+5V) 14 A4 SUBSTRATE BIAS 4 GEN. RAS CLOCK GEN. No1 23 WRITE 3 CAS CLOCK CLOCK WE GEN. No2 GEN. MODE CONTROL DATA INPUT BUFFER ADDRESS COLUMN BUFFER DECODER 9-12, 14-18 1, 2, 24, 25 SENSE AMP. A0-A8 DQ1-DQ4 I/O GATE PRE- DECODER DATA OUTPUT 1,048,576-BIT BUFFER MEMORY REFRESH CELL ADDRESS COUNTER 2