1 Mbit EPROM, 70 ns — the firmware store for legacy 8-bit buses
The Cypress CY27C010-70ZC is a 1 Mbit parallel EPROM organized as 128K x 8, with a 70 ns access time and a 4.5 V supply rail. It sits in a 32-pin TSOP surface-mount package and is rated for commercial temperature (0°C to 70°C). This part is a non-volatile memory for boot code, lookup tables, or configuration data in systems that use an 8-bit data bus and a byte-wide address map — think embedded controllers, test equipment, or legacy telecom line cards where the firmware is programmed once and never field-updated.
The parallel interface uses /CE, /OE, and /PGM control lines with a standard 8-bit data bus.
EPROM, not EEPROM or Flash — no field updates
This is a UV-erasable EPROM (the windowed package variant) or OTP EPROM (the non-windowed version). The memory format is EPROM, meaning the device is programmed once with a standard EPROM programmer and cannot be electrically erased in-system.
Commercial temperature grade — indoor use only
It is not specified for automotive under-hood, outdoor industrial, or military applications. If your BOM calls for an extended-temperature EPROM, look for a -70ZI or -70ZC variant with the industrial suffix.
Active lifecycle — no LTB, but plan for supply continuity
For a design that depends on this part, a second-source or a lifetime buy of the expected production volume is prudent.