IDT723641

The IDT723641 is a monolithic highspeed, low-power, CMOS clocked FIFO memory. It supports clock frequencies up to 67 MHz and has read access times as fast as 12ns. The 512/1024/2048 x 36 dual-port SRAM FIFO buffers data from port A to Port B. The FIFO memory has retransmit capability, which allows previously read data to be accessed again. The FIFO has flags to indicate empty and full conditions and two programmable flags (almost full and almost empty) to indicate when a selected number of words is stored in memory. Communication between each port may take place with two 36-bit mailbox registers. Each mailbox register has a flag to signal when new mail has been stored. Two or more devices of the IDT723641 may be used in parallel to create wider data paths. Expansion is also possible in word depth.

The IDT723641 is a clocked FIFO, which means each port employs a synchronous interface. All data transfers through a port are gated to the LOW-to-HIGH transition of a continuous (free-running) port clock by enable signals. The continuous clocks for each port are independent of one another and can be asynchronous or coincident. he enables for each port are arranged to provide a simple interface between microprocessors and/or buses with synchronous control.

The input-ready (IR) flag and almost-full (AF) flag of the FIFO are two-stage synchronized to CLKA. The output-ready (OR) flag and almost-empty (AE) flag of the FIFO are twostage synchronized to CLKB. Offset values for the almost-full and almost empty flags of the FIFO can be programmed from port A or through a serial input.