The CY7C109B/CY7C1009B is a high-performance CMOS static RAM organized as 131,072 words by eight bits. Easy memory expansion is provided by an active LOW Chip Enable (/CE1 ), an active HIGH Chip Enable (CE2 ), an active LOW Output Enable (/OE), and three-state drivers. Writing to the device is accomplished by taking Chip Enable One (/CE1 ) and Write Enable (/WE) inputs LOW and Chip Enable Two (CE2 ) input HIGH. Data on the eight I/O pins (I/O 0 through I/O 7 ) is then written into the location specified on the address pins (A 0 through A 16 ).

Reading from the device is accomplished by taking Chip Enable One (/CE1 ) and Output Enable (/OE) LOW while forcing Write Enable (/WE) and Chip Enable Two (CE2 ) HIGH. Under these conditions, the contents of the memory location specified by the address pins will appear on the I/O pins. The eight input/output pins (I/O 0 through I/O 7 ) are placed in a high-impedance state when the device is deselected (/CE1 HIGH or CE2 LOW), the outputs are disabled (/OE HIGH), or during a write operation (/CE1 LOW, CE2 HIGH, and /WE LOW).

The CY7C109B is available in standard 400-mil-wide SOJ and 32-pin TSOP type I packages. The CY7C1009B is available in a 300-mil-wide SOJ package. The CY7C1009B and CY7C109B are functionally equivalent in all other respects.