512 Mbit parallel NOR flash — what you are getting
The Cypress S29GL512T12DHN020 is a 512 Mbit parallel NOR flash from the GL-T family, organized as 64M x 8 bits. The 120 ns access time is the number to watch when matching it to your memory controller's timing budget — it is the slowest read cycle the part guarantees.
At 120 ns, this part is on the slower side of the GL-T family. The sibling S29GL512T11TFIV20 clocks 110 ns access, which buys 10 ns of margin on a fast controller but costs a narrower temperature range (85°C vs 125°C). If your system already runs at 120 ns or slower, this part fits without retiming; if you are pushing a 100 MHz bus, you will hit wait states.
The 125°C ceiling is the key differentiator from the 85°C sibling — if your ambient hits 105°C, the 85°C part derates or fails; this one keeps running.
Lifecycle and sourcing posture
No LTB risk for current production.