Active 256Kbit SRAM for 5V legacy bus designs
The CY62256LL-70ZI: The 70 ns access time sets the read/write cycle ceiling — this is the window the bus controller must respect for valid data at the outputs. For a system clocked at 10 MHz (100 ns period), the 70 ns access leaves 30 ns for address setup and hold, which is workable with careful PCB trace length matching.
The CY62256LL-70ZI is supplied in a 28-TSSOP package with a body width of 0.465 inches (11.80 mm) and is designated as 28-TSOP I. This is a surface-mount, narrow-body TSOP footprint common for parallel SRAMs in the 256 Kbit to 1 Mbit density range. The 0.65 mm typical lead pitch (standard for 28-pin TSOP I) requires a PCB with fine-pitch soldering capability but is routable on two-layer boards with proper trace spacing. The package is supplied in Bulk. The 28-TSOP I footprint is shared with other industry-standard 256Kbit SRAMs, so the board layout is not unique to this part.
Compliance and lifecycle posture
This part is RoHS non-compliant. The terminations use lead-bearing solder, which is exempt under certain RoHS categories (e.g., Annex III exemptions for high-reliability applications) but requires documentation for EU-market shipments.