My Apple 1 replica uses MK4027N-1 RAMs so I'm wondering if an MK4027N-3 will also work?
..
Here are some differences I noticed from the datasheet.
MK4027N-1 - 120ns access time, 320ns cycle
MK4027N-3 - 200ns access time, 375ns cycle
My Apple 1 replica uses MK4027N-1 RAMs so I'm wondering if an MK4027N-3 will also work?
..
Here are some differences I noticed from the datasheet.
MK4027N-1 - 120ns access time, 320ns cycle
MK4027N-3 - 200ns access time, 375ns cycle
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I'm currently using Motorola MCM4027AC3s in mine. They match the specs you list and they work perfect so you should be fine. I think the 4027s are a bit more forgiving than the 4096s but that's just me.
Maximum Access Time = 200 ns - MCM4027AC3
Maximum Read and Write Cycle Time = 375 ns - MCM4027AC3
Should still work.
[quote=PROMetheus]
I'm currently using Motorola MCM4027AC3s in mine. They match the specs you list and they work perfect so you should be fine. I think the 4027s are a bit more forgiving than the 4096s but that's just me.
Maximum Access Time = 200 ns - MCM4027AC3
Maximum Read and Write Cycle Time = 375 ns - MCM4027AC3
[/quote]
Do you find the Motorola chips draw more current than the MK4027? I tried them in my Mimeo to free up some authentic ram and it made LM340-12 regulator run hot where it needed a heat sink. Same with Intel ceramic RAM. They worked fine, just drew more current. Didn't have that problem with MK4096 chips which was how I went on that Mimeo.
Cheers,
Corey
That's a really good question. The data sheets show an IDD1 of 35mA on MCM4027 and MK4027 vs. 25 mA for the 4096-11 but I don't know what they are really drawing in use. I'll have to check. Now, where did I put my IR thermometer...
To the OP, the MK4096N-11 that I see used on original boards show an access time of 350 ns. Your 200 ns RAMs should be no problem.
[quote=PROMetheus]
I'm currently using Motorola MCM4027AC3s in mine. They match the specs you list and they work perfect so you should be fine. I think the 4027s are a bit more forgiving than the 4096s but that's just me.
Maximum Access Time = 200 ns - MCM4027AC3
Maximum Read and Write Cycle Time = 375 ns - MCM4027AC3
[/quote]
That's great, thank you!