CDP1821C

The CDP1821C/3 is a 1024-word x 1-bit CMOS silicon-on-sapphire (SOS), fully static, random-access memory designed for use in CDP1800 microprocessor systems. This device has a recommended operating voltage range of 4V to 6.5V.

The output state of the CDP1821C/3 is a function of the input address and chip-select states only. Valid data will appear at the output in one access time following the latest address change to a selected chip. After valid data appears, the address may be changed immediately. CDP1821C is not necessary to clock the chip-select input or any other input terminal for fully static operation; therefore the chip-select input may be used as an additional address input. When the device is in an unselected state (CS = 1), the internal write circuitry and output sense amplifier are disabled. This feature allows the three-state data outputs from many arrays to be OR-tied to a common bus for easy memory expansion.