AS9C25256M2018L

device, organized as 524,288/262,144 * 18 bits. AS9C25256M2018L incorporates a selectable Flow-Through/Pipeline output feature for user flexibility. Clockto-data valid time is 2.8ns at 250 MHz for "Pipeline output" mode of operation.

Each port contains a 19/18 bit linear burst counter on the input address register that can loop through the whole address sequence. After externally loading the counter with the initial address, AS9C25256M2018L can be Incremented or Held for the next cycle. A new address of AS9C25256M2018L can also be Loaded or the "Previous Loaded" address can be re-accessed (Repeated) using counter controls (More description to follow). The Registers on control, data, and address inputs provide minimal setup and hold times.

The memory array of AS9C25256M2018L utilizes Dual-Port memory cells to allow simultaneous access of any address from both ports. A particular port can write to a certain location while another port is reading from the same location, but the validity of read data is not guaranteed. However, the reading port of AS9C25256M2018L is informed about the possible collision through its collision alert signal. The result of writing to the same location by more than one port at the same time is undefined.

The Asynchronous Output Enable input pin of AS9C25256M2018L allows asynchronous disabling of output buffers at any given time. The Byte Enable inputs allow individual byte read/write operations (refer Byte Control Truth Table). An automatic power down feature, AS9C25256M2018L controlled by CE0 and CE1, permits the on-chip circuitry of each port to enter a very low standby power mode.

AS9C25512M2018L/AS9C25256M2018L can support an operating voltage of either 3.3V or 2.5V on either or both ports, which is controlled by the OPT pins. The power supply for the core of the device (VDD) is at 2.5V. AS9C25256M2018L is available in 256-pin Ball Grid Array (BGA), 208-pin fine pitch Ball Grid Array (fpBGA) and 144-pin Thin Quad Flatpack (TQFP)