SN74BCT648

• State-of-the-Art BiCMOS Design Significantly Reduces I_CCZ
• Independent Registers for A and B Buses
• Multiplexed Real-Time and Stored Data
• Inverting Data Paths
• Power-Up High-Impedance Mode
• Package Options Include Plastic Small-Outline (DW) Packages, Ceramic Chip Carriers (FK) and Flatpacks (W), and Standard Plastic and Ceramic 300-mil DIPS (JT, NT)

These SN74BCT648 devices consist of bus transceiver circuits with 3-state outputs, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the input bus or from the internal registers. Data on the A or B bus will be clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental busmanagement functions that can be performed with the 4BCT648.

SN74BCT648 Output-enable (OE) and direction-control (DIR) inputs are provided to control the transceiver functions. In the transceiver mode, data present at the high-impedance port may be stored in either register or in both. The select control (SAB and SBA) can multiplex stored and real-time (transparent mode) data. The direction control determines which bus will receive data when OE is active (low). In the isolation mode (OE high), A data may be stored in one register and/or B data may be stored in the other register.

When an SN74BCT648 output function is disabled, the input function is still enabled and may be used to store and transmit data. Only one of the two buses, A or B, may be driven at a time.

The SN54BCT648 is characterized for operation over the full military temperature range of 55°C to 125°C. The SN74BCT648 is characterized for operation from 0°C to 70°C.