uPD2114LC / 2114
The 2114 is a 4096-bit static random access memory (RAM) with 1024 words by 4-bit organisation. The NEC version is uPD2114LC, and Motorola version MCM2114.
Compatible Intel Version
Intel also made compatible ICs and here is some information I managed to find from my 1983 Intel Memory Components Handbook about the 2114AL.
- Low power and High Speed
- Identical Cycle and Access Times
- Single +5 V Supply
- High-Density 18-pin Package
- No Clock or Timing Strobe Required
- Directly TTL Compatible
- Common Data I/O using tri-state outputs
Access Times
Device | Access Time (ns) | Current (mA) |
2114AL-1 | 100 | 40 |
2114AL-2 | 120 | 40 |
2114AL-3 | 150 | 40 |
2114AL-4 | 200 | 40 |
2114A-4 | 200 | 70 |
2114A-5 | 250 | 70 |
2148 | ||
D2148H-3 | 55 | 180 |
D2148H | 70 | 180 |
D2148HL | 70 | 125 |
2149 | ||
D2149H-2 | 45 | 180 |
D2149H-3 | 55 | 180 |
D2149H | 70 | 180 |
D2149HL | 70 | 125 |
Intel's D2148 is also compatible with the industry standard 2114A. Based on HMOS II technology, it has the same memory configuration of 1024 × 4-bit, 18 pin package, tri-state outputs, and requires a single +5 V power supply. As you can see from the table above, it has much faster memory access time, which is a good thing. I have not used this on the ZX80 but it has a good chance of working and there is always some old stock available on eBay.
The D2148H is for power critical applications and has an automatic power down function; however, Intel also created a non-power down version, D2149H, which is also pinout compatible with the 2114A and has a 1024 × 4-bit organisation. The D2149H-2 version is even faster with an address access time of 45 ns. The ceramic package version of this chip is the 21L14. If you can afford the ceramic package with gold pins then it is even better for your vintage ZX80 computer.