I wrote all "1"s into a 28C64 EEPROM from address 0 to 15 (the rest address lines tied to GND).
Then I use a 4-bit counter (10HZ clock) to drive the address lines from 0 to 15 to read the 28C64. I noticed that there is a short voltage drop (output goes from high to nearly zero and back up to high, last about 160ns) when the address changes.
It happens somewhat randomly: the voltage drops may happen when address changes from 1 to 2, or from 5 to 6, etc. Then I tried two another same 28C64 chips, one does not have this voltage drop, and one does.
The data sheet used cross marks during address change. http://www.jameco.com/Jameco/Products/ProdDS/74827.pdf
I am quite confused, it is normal for the output to drop during address transition? thanks!
Here is the scope captured the voltage drop. The total time is about 240ns, the chip is -25.