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Examples of 41128 class RAM chips

128K by 1 bit, in a particular pin configuration ('pinout').
128K by 1 bit = 131,072 bits

The 41128 consists of two stacked (piggybacked) chips.  The top chip is slighly different to the bottom chip; RAS is pin 3 on one chip, pin 4 on the other chip.

The 41128 is by no means the first and only stacked chip arrangement.  As an example, click here to see a 4132 RAM chip, dated 1981.

Japanese makers tend not to print prefixes on ICs and transistors.  In photos below, it is seen that Oki is in that category for the 41128.


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 41128 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		 Refresh
Cycles		 Photo Source Data Sheet *   Comment
Hitachi HM48128P-2 150 ns ? photo     Yes Hitachi appear to use -2 for 150 ns (e.g. see their 4116 and 4164 chips).
                 
Micron MT1128-15 150 ns ? photo     ? I do not have this chip.
Micron MT1128-20 200 ns ? photo     N/S May not be suitable for the IBM 5170.  See here.
                 
Mostek MK4128N-15 150 ns ? photo     Yes  
Mostek MK4128N-20 200 ns ? photo     N/S May not be suitable for the IBM 5170.  See here.
                 
Oki MSM37S64A-15 150 ns 128cycle/2ms photo   datasheet Yes  
Oki MSM37S64A-20 200 ns 128cycle/2ms     datasheet N/S May not be suitable for the IBM 5170.  See here.
                 
Samsung KM4128U-15 150 ns 256cycle/4ms photo   datasheet Yes  
Samsung KM4128U-20 200 ns 256cycle/4ms     datasheet N/S May not be suitable for the IBM 5170.  See here.
                 
Texas Instruments ZA1250NL 150 ns ? photo     Yes This is the most common RAM chip found on an IBM 5170 motherboard of type 1
Texas Instruments TMS41128A-15NL 150 ns 256cycle/4ms photo     Yes  
Texas Instruments TMS41128B-15NL 150 ns 256cycle/4ms   41128 list 1 datasheet Yes  


* Test on a 5170 motherboard of type 1
  Yes = Tested successfully by me.
  N/S = May not be suitable for the IBM 5170.  See here.