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Examples of 41256 class RAM chips

256K by 1 bit, in a particular pin configuration ('pinout').
256K by 1 bit = 262,144 bits

These chips have a 9-bit address (row address is 9 bits, and column address is 9 bits).  If we assume a square shaped cell matrix, that corresponds to a cell matrix of 512 rows by 512 columns.  But you will see below that they use '256cycle' refresh, indicating only 256 rows.  The explanation is that the cell matrix is rectangular, 256 rows by 1024 columns. For more information, see the 'Rectangular cell matrices' section of here.

Note that some makers did not use "41256" in their part number.  That is because makers did not need to adhere to a common naming standard.  Some makers may have even purposely not used 41256 to avoid possible litigation action.

DIP packages (of plastic and ceramic) listed only - LCC and SIP and ZIP packages are omitted.

Japanese makers tend not to print prefixes on ICs and transistors.  In photos below, it is seen that at least NEC and Oki are in that category for the 41256.



IMPORTANT:  The table below does not show all of the chip's characteristics/specifications (that is what a data sheet is for).
Apart from major differences (such as access time), there can be differences (some subtle) that result in a particular 41256 chip not being suitable for your purpose.
Sometimes, a device maker will produce a list of RAM chips known to be compatible with their device (example).


Make Part Number Access
Time		 NMOS/
CMOS		 Refresh
Cycles		 Photo Source Source Source Source Data Sheet   Comment
Austin AS4C1259-10 100 ns CMOS 256cycle/4ms           datasheet Clone of MT1259?  (Austin acquired Micron - see page 4)
Austin AS4C1259-12 120 ns CMOS 256cycle/4ms           datasheet Clone of MT1259?  (Austin acquired Micron - see page 4)
Austin AS4C1259-15 150 ns CMOS 256cycle/4ms           datasheet Clone of MT1259?  (Austin acquired Micron - see page 4)
                       
Fujitsu MB81256-10 100 ns NMOS 256cycle/4ms photo     41256 list 4 41256 list 5 datasheet  
Fujitsu MB81256-12 120 ns NMOS 256cycle/4ms photo     41256 list 4 41256 list 5 datasheet  
Fujitsu MB81256-15 150 ns NMOS 256cycle/4ms photo     41256 list 4 41256 list 5 datasheet  
Fujitsu MB81256-80 80 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4 41256 list 5    
                       
GoldStar GM71256-10 100 ns NMOS 256cycle/4ms           datasheet  
GoldStar GM71256-12 120 ns NMOS 256cycle/4ms           datasheet  
GoldStar GM71256-15 150 ns NMOS 256cycle/4ms photo         datasheet  
GoldStar GM71C256A-10 100 ns CMOS 256cycle/4ms       41256 list 4 41256 list 5 datasheet Datasheet contains "All inputs and output TTL compatible"
GoldStar GM71C256A-70 70 ns CMOS 256cycle/4ms       41256 list 4 41256 list 5 datasheet Datasheet contains "All inputs and output TTL compatible"
GoldStar GM71C256A-80 80 ns CMOS 256cycle/4ms       41256 list 4 41256 list 5 datasheet Datasheet contains "All inputs and output TTL compatible"
                       
Hitachi     HM50256-12 120 ns NMOS 256cycle/4ms           datasheet Ceramic case.
Hitachi     HM50256-15 150 ns NMOS 256cycle/4ms           datasheet Ceramic case.
Hitachi     HM50256-20 200 ns NMOS 256cycle/4ms           datasheet Ceramic case.
Hitachi     HM50256P-12 120 ns NMOS 256cycle/4ms photo 41256 list 1       datasheet Plastic case.
Hitachi     HM50256P-15 150 ns NMOS 256cycle/4ms photo 41256 list 1 41256 list 2     datasheet Plastic case.
Hitachi     HM50256P-20 200 ns NMOS 256cycle/4ms   41256 list 1       datasheet Plastic case.
                       
Hitachi     HM51256LP-8 85 ns CMOS 256cycle/32ms     41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256LP-10 100 ns CMOS 256cycle/32ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256LP-12 120 ns CMOS 256cycle/32ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256LP-15 150 ns CMOS 256cycle/32ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256P-8 85 ns CMOS 256cycle/4ms photo   41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256P-10 100 ns CMOS 256cycle/4ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256P-12 120 ns CMOS 256cycle/4ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
Hitachi     HM51256P-15 150 ns CMOS 256cycle/4ms   41256 list 1 41256 list 4 41256 list 5 41256 list 6 datasheet Datasheet contains "Input and output: TTL compatible"
                       
Hyundai HY53C256L-10 100 ns CMOS 256cycle/4ms     41256 list 3 41256 list 4   datasheet "L" on rear page of datasheet
Hyundai HY53C256L-70 70 ns CMOS 256cycle/4ms     41256 list 3 41256 list 4   datasheet "L" on rear page of datasheet
Hyundai HY53C256L-80 80 ns CMOS 256cycle/4ms     41256 list 3 41256 list 4   datasheet "L" on rear page of datasheet
Hyundai   HY53C256LS-10 100 ns CMOS 256cycle/4ms photo     41256 list 4   datasheet "LS" on rear page of datasheet
Hyundai   HY53C256LS-70 70 ns CMOS 256cycle/4ms photo     41256 list 4   datasheet "LS" on rear page of datasheet
Hyundai   HY53C256LS-80 80 ns CMOS 256cycle/4ms       41256 list 4   datasheet "LS" on rear page of datasheet
                       
Intel P21256-06 60 ns NMOS 256cycle/4ms           datasheet 1991 datasheet.  "-06" referred to in final page of datasheet
Intel P21256-07 70 ns NMOS 256cycle/4ms           datasheet 1991 datasheet.  "-07" referred to in final page of datasheet
Intel P21256-08 80 ns NMOS 256cycle/4ms photo         datasheet 1991 datasheet.   
Intel P21256-10 100 ns NMOS 256cycle/4ms           datasheet 1991 datasheet.  "-10" referred to in final page of datasheet
                       
Intel P51C256H-10 100 ns CMOS 256cycle/4ms           datasheet 1985 datasheet.  "Ripplemode"
Intel P51C256H-12 120 ns CMOS 256cycle/4ms           datasheet 1985 datasheet.  "Ripplemode"
Intel P51C256H-15 150 ns CMOS 256cycle/4ms           datasheet 1985 datasheet.  "Ripplemode"
Intel P51C256H-20 200 ns CMOS 256cycle/4ms photo         datasheet 1985 datasheet.  "Ripplemode"
                       
Micron MT1256-10 100 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Micron MT1256-12 120 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Micron MT1256-15 150 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
                       
Micron MT1259-10 100 ns CMOS 256cycle/4ms photo   41256 list 3     datasheet Datasheet contains "All inputs, ... are fully TTL compatible"
Micron MT1259-12 120 ns CMOS 256cycle/4ms     41256 list 3     datasheet Datasheet contains "All inputs, ... are fully TTL compatible"
Micron MT1259-15 150 ns CMOS 256cycle/4ms     41256 list 3     datasheet Datasheet contains "All inputs, ... are fully TTL compatible"
                       
Mitsubishi     M5M4256AP-10 100 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4 41256 list 5 datasheet  
Mitsubishi     M5M4256AP-12 120 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4 41256 list 5 datasheet  
Mitsubishi     M5M4256AP-15 150 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4 41256 list 5 datasheet  
Mitsubishi     M5M4256AP-85 85 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4 41256 list 5 datasheet  
Mitsubishi     M5M4256P-10 100 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Mitsubishi     M5M4256P-12 120 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Mitsubishi     M5M4256P-15 150 ns NMOS 256cycle/4ms photo   41256 list 3 41256 list 4      
Mitsubishi     M5M4256P-20 200 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Mitsubishi     M5M4256S-12 120 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Mitsubishi     M5M4256S-15 150 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Mitsubishi     M5M4256S-20 200 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
                       
Mosel MS51256-10 100 ns ? 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Mosel MS51256-12 120 ns ? 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Mosel MS51256-15 150 ns ? 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
                       
Mostek                     Thomson acquired Mostek in 1985
                       
Motorola     MCM6256-10 100 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Motorola     MCM6256-12 120 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Motorola     MCM6256-15 150 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Motorola     MCM6256BP-10 100 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4   datasheet  
Motorola     MCM6256BP-12 120 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4   datasheet  
Motorola     MCM6256BP-15 150 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4   datasheet  
                       
National Semiconductor NMC41256 ? ? ?     NMC41256        
                       
NEC µPD41256C-10 100 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4 41256 list 5 datasheet As shown in photo, the prefix of "µP" is not printed.
NEC µPD41256C-12 120 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4 41256 list 5 datasheet As shown in photo, the prefix of "µP" is not printed.
NEC µPD41256C-15 150 ns NMOS 256cycle/4ms photo 41256 list 1   41256 list 4 41256 list 5 datasheet As shown in photo, the prefix of "µP" is not printed.
NEC µPD41256D-10 100 ns NMOS ?   41256 list 1   41256 list 4 41256 list 5    
NEC µPD41256D-12 120 ns NMOS ?   41256 list 1   41256 list 4 41256 list 5    
NEC µPD41256D-15 150 ns NMOS ?   41256 list 1   41256 list 4 41256 list 5    
                       
Oki    MSM41256-15 150 ns NMOS ? photo     41256 list 4     As shown in photo, the prefix of "MS" is not printed.
Oki    MSM41256A-10 100 ns NMOS 256cycle/4ms photo     41256 list 4   datasheet As shown in photo, the prefix of "MS" is not printed.
Oki    MSM41256A-12 120 ns NMOS 256cycle/4ms       41256 list 4   datasheet  
Oki    MSM41256A-15 150 ns NMOS 256cycle/4ms       41256 list 4   datasheet  
                       
Oki     MSM51C256-10 100 ns CMOS 256cycle/4ms         41256 list 6 datasheet Datasheet contains "its I/O pins are TTL compatible"
Oki     MSM51C256-80 80 ns CMOS 256cycle/4ms         41256 list 6 datasheet Datasheet contains "its I/O pins are TTL compatible"
                       
Panasonic / Matsushita     MN41256-12 120 ns NMOS 256cycle/4ms photo   41256 list 3     datasheet  
Panasonic / Matsushita     MN41256-15 150 ns NMOS 256cycle/4ms     41256 list 3     datasheet  
Panasonic / Matsushita     MN41256A-08 80 ns NMOS 256cycle/4ms photo 41256 list 1 41256 list 3        
Panasonic / Matsushita     MN41256A-10 100 ns NMOS 256cycle/4ms   41256 list 1 41256 list 3        
Panasonic / Matsushita     MN41256A-12 120 ns NMOS 256cycle/4ms   41256 list 1 41256 list 3        
                       
Samsung     KM41256-10 100 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Samsung     KM41256-12 120 ns NMOS 256cycle/4ms     41256 list 3 41256 list 4      
Samsung     KM41256-15 150 ns NMOS 256cycle/4ms photo   41256 list 3 41256 list 4      
Samsung     KM41256AP-10 100 ns NMOS 256cycle/4ms   41256 list 1 41256 list 3 41256 list 4   datasheet  
Samsung     KM41256AP-12 120 ns NMOS 256cycle/4ms   41256 list 1 41256 list 3 41256 list 4   datasheet  
Samsung     KM41256AP-15 150 ns NMOS 256cycle/4ms photo 41256 list 1 41256 list 3 41256 list 4   datasheet  
                       
Samsung     KM41C256P-7 70 ns CMOS 256cycle/4ms photo       41256 list 6 datasheet Datasheet contains "TTL compatible inputs and output"
Samsung     KM41C256P-8 80 ns CMOS 256cycle/4ms photo       41256 list 6 datasheet Datasheet contains "TTL compatible inputs and output"
Samsung     KM41C256P-10 100 ns CMOS 256cycle/4ms photo       41256 list 6 datasheet Datasheet contains "TTL compatible inputs and output"
                       
Sanyo LM33256G-12 120 ns NMOS ? photo           Photo of Commodore PC 20-III motherboard
Sanyo LM33256G-15 150 ns NMOS ? photo           Photo of Commodore Amiga 2000 motherboard
Sanyo LM33256K-15 150 ns NMOS ?           datasheet  
Sanyo LM33256N-15 150 ns NMOS ? photo         datasheet  
                       
Sharp LH21256-10 100 ns NMOS 256cycle/4ms     41256 list 3     datasheet  
Sharp LH21256-12 120 ns NMOS 256cycle/4ms photo   41256 list 3     datasheet  
Sharp LH21256-15 150 ns NMOS 256cycle/4ms     41256 list 3     datasheet  
                       
Siemens HYB41256-10 100 ns NMOS 256cycle/4ms   41256 list 1       datasheet  
Siemens HYB41256-12 120 ns NMOS 256cycle/4ms photo 41256 list 1       datasheet  
Siemens HYB41256-15 150 ns NMOS 256cycle/4ms   41256 list 1       datasheet  
                       
Texas Instruments SMJ4256-12 JD 120 ns NMOS 256cycle/4ms   41256 list 1       datasheet SMJ=military
Texas Instruments SMJ4256-15 JD 150 ns NMOS 256cycle/4ms   41256 list 1       datasheet SMJ=military
Texas Instruments SMJ4256-20 JD 200 ns NMOS 256cycle/4ms   41256 list 1       datasheet SMJ=military
Texas Instruments     TMS4256-8 80 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4 41256 list 5 datasheet  
Texas Instruments     TMS4256-10 100 ns NMOS 256cycle/4ms photo 41256 list 1 41256 list 3 41256 list 4 41256 list 5 datasheet  
Texas Instruments     TMS4256-12 120 ns NMOS 256cycle/4ms   41256 list 1 41256 list 3 41256 list 4 41256 list 5 datasheet  
Texas Instruments     TMS4256-15 150 ns NMOS 256cycle/4ms photo 41256 list 1 41256 list 3 41256 list 4 41256 list 5 datasheet Also 41256 list 2
Texas Instruments     TMS4256-20 200 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4 41256 list 5 datasheet  
                       
Thomson MKB45F56P-80 100 ns NMOS ?   41256 list 1         MKB=military         Thomson acquired Mostek in 1985
Thomson MKB45F56P-81 120 ns NMOS ?   41256 list 1         MKB=military         Thomson acquired Mostek in 1985
Thomson MKB45F56P-82 150 ns NMOS ?   41256 list 1         MKB=military         Thomson acquired Mostek in 1985
                       
Toshiba    TMM41256AP-10 100 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4   datasheet  
Toshiba    TMM41256AP-12 120 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4   datasheet  
Toshiba    TMM41256AP-15 150 ns NMOS 256cycle/4ms   41256 list 1   41256 list 4   datasheet  
Toshiba    TMM41256P-15 150 ns NMOS ? photo     41256 list 4      
                       
Toshiba TC51256P-60 60 ns CMOS 256cycle/4ms     41256 list 3   41256 list 5 datasheet Probably TTL compatible
Toshiba TC51256P-70 70 ns CMOS 256cycle/4ms     41256 list 3   41256 list 5 datasheet Probably TTL compatible
Toshiba TC51256P-80 80 ns CMOS 256cycle/4ms     41256 list 3   41256 list 5 datasheet Probably TTL compatible
                       
Vitelic     V53C256-10 100 ns CMOS 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256-12 120 ns CMOS 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256-70 70 ns CMOS 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256-80 80 ns CMOS 256cycle/4ms     41256 list 3       In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256AP10 100 ns CMOS 256cycle/4ms           datasheet In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256AP60 60 ns CMOS 256cycle/4ms           datasheet In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256AP70 70 ns CMOS 256cycle/4ms           datasheet In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256AP80 80 ns CMOS 256cycle/4ms           datasheet In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
Vitelic     V53C256P80 80 ns CMOS 256cycle/4ms photo           In 1991, Mosel and Vitelic merged to form Mosel Vitelic Inc.
                       
Western Electric WCM41256FX-20 200 ns ? ?     41256 list 2       Western Electric supplied AT&T
                       
ZMD U61256C ? ? ? photo           ZMD = Zentrum Mikroelektronik Dresden