M48Z02 (16Kbit ZEROPOWER SRAM) is TTL compatible?
As Eugene Sh. said, TTL/CMOS problem is about logic level.

If fact the two different technologies use different voltage level to send logic high signal (1) or low signal (0).

Here an image (from allaboutcircuits.com) that can explain this concept:



In the M48Z02 datasheet  it is written:

|      Parameter      |  Min  |   Max   | Unit |
------------------------------------------------
| Input low voltage   | –0.3  |   0.8   |  V   |
| Input high voltage  |  2.2  | Vcc+0.3 |  V   |
| Output low voltage  |       |   0.4   |  V   |
| Output high voltage |  2.4  |         |  V   |


Putting data together, during communication from a TTL chip to M48Z02:


TTL -> M48Z02:


Logic 0: communication ok, 0 > –0.3 and 0.5 &lt; 0.8
Logic 1: communication ok, 2.7 > 2.2 and 5 &lt; Vcc+0.3



During communication from M48Z02 to TTL:


M48Z02 -> TTL:


Logic 0: communication ok, 0.4 &lt; 0.8
Logic 1: communication ok, 2.4 > 2



In conclusion, they can communicate correctly.