SN74ABT3612

Supply voltage range, V_CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 0.5 V to 7 V
Input voltage range, V_I (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 V to V_CC + 0.5 V
Output voltage range, V_O (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . 0.5 V to V_CC + 0.5 V
Input clamp current, I_IK (V_I < 0 or V_I > V_CC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
Output clamp current, IO_K (V_O < 0 or V_O > V_CC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Continuous output current, I_O (V_O = 0 to V_CC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Continuous current through V_CC or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±500 mA
Package thermal impedance, _JA (see Note 2): PCB package . . . . . . . . .. . . . . . . . . 28°C/W
                                                                           PQ package . . . . . . . . . . . . . . . . . . 46°C/W
Storage temperature range, T_stg . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 65°C to 150°C

† Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTES: 1. The input and output voltage ratings may be exceeded provided the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51.

The SN74ABT3612 is a high-speed, low-power BiCMOS bidirectional clocked FIFO memory. It supports clock frequencies up to 67 MHz and has read access times as fast as 10 ns. Two independent 64 × 36 dual-port SRAM FIFOs in this device buffer data in opposite directions. Each 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 can bypass the FIFOs via two 36-bit mailbox registers. Each mailbox register has a flag to signal when new mail has been stored. Parity is checked passively on each port and can be ignored if not desired. Parity generation can be selected for data read from each port. Two or more devices can be used in parallel to create wider datapaths.

The SN74ABT3612 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 port clock by enable signals. The clocks for each port are independent of one another and can be asynchronous or coincident. The enables for each port are arranged to provide a simple bidirectional interface between microprocessors and/or buses with synchronous control.The full flag (FFA,FFB) and almost-full (AFA, AFB) flag of a FIFO are two-stage synchronized to the port clock that writes data to its array. The empty flag (EFA, EFB) and almost-empty (AEA, AEB) flag of a FIFO are two-stage synchronized to the port clock that reads data from its array.

The SN74ABT3612 is characterized for operation from 0°C to 70°C.

For more information on SN74ABT3612 , see the following application reports:
· FIFO Mailbox-Bypass Registers: Using Bypass Registers to Initialize DMA Control (literature number SCAA007)
· Parity-Generate and Parity-Check Features for High-Bandwidth-Computing FIFO Applications (literature number SCAA015)
· Metastability Performance of Clocked FIFOs (literature number SCZA004)