DRAM 256k x 4

Cross-Reference

BRAND	TAG	NUMBER	PIN COUNT	OUTPUT	MARKINGS
OKI	MSM	514256	DIP20-300mil SOJ26/20-300mil ZIP20	.	M514256 M514256C MSM514256A
Samsung	KM	44C256	DIP20-300mil SOJ20 ZIP20	.	KM44C256 KM44C256CP
Samsung	KM	44C258	DIP20-300mil SOJ20 ZIP20	.	KM44C258
Siemens	HYB	514256	DIP20-300mil SOJ26/20-300mil	.	HYB514256 HYB514256B
Toshiba	TC	514256	DIP20-300mil SOJ26/20-300mil ZIP20	.	TC514256 TC514256A
Note: 256= Fast page mode 258= Static column mode

Dynamic Random-Access Memory 256K x 4

Size

bit	Byte (padded 0000xxxx)	Byte (unpadded)	Hex
1Mb	256KB	128KB	100000hex

Pinout

         DIP20 SOJ20
         +---\/---+
     DQ1 | 1    20| Vss
     DQ2 | 2    19| DQ4
      *W | 3    18| DQ3
    *RAS | 4    17| *CAS
      NC | 5    16| *G
      A0 | 6    15| A8
      A1 | 7    14| A7
      A2 | 8    13| A6
      A3 | 9    12| A5
     Vcc |10    11| A4
         +--------+

        ZIP20
          ^
    *G  1 |
          |  2 *CAS
   DQ3  3 |
          |  4 DQ4
   Vss  5 |
          |  6 DQ1
   DQ2  7 |
          |  8 *W
  *RAS  9 |
          | 10 NC
    A0 11 |
          | 12 A1
    A2 13 |
          | 14 A3
   Vcc 15 |
          | 16 A4
    A5 17 |
          | 18 A6
    A7 19 |
          | 20 A8
          -

       SOJ26/20-300mil
         +---\/---+
     DQ1 | 1    26| Vss
     DQ2 | 2    25| DQ4
     *WE | 3    24| DQ3
    *RAS | 4    23| *CAS
      NC | 5    22| *OE
         | 6    21|   
         | 7    20|   
         | 8    19|   
      A0 | 9    18| A8
      A1 |10    17| A7
      A2 |11    16| A6
      A3 |12    15| A5
     Vcc |13    14| A4
         +--------+

External links

DRAM page on wikipedia

Files

• 
  KM44C256 KM44C258 Datasheet
• 
  HYB514256 Datasheet
• 
  MSM514256A Datasheet
• 
  TC514256 Datasheet