SN74FB2033A

    The SN74FB2033A is an  8-bit transceiver featuring a split input (AI) and output (AO) bus on the TTL-level A port. The common-I/O, open-collector B port operates at backplane transceiver logic (BTL) signal levels.

    The logic element for data flow in each direction is configured by two mode inputs (IMODE1 and IMODE0 for B-to-A, OMODE1 and OMODE0 for A-to-B) as a buffer, a D-type flip-flop, or a D-type latch. When configured in the buffer mode, the inverted input data appears at the output port. In the SN74FB2033A flip-flop mode, data is stored on the rising edge of the appropriate clock input (CLKAB/LEAB or CLKBA/LEBA). In the latch mode, the clock inputs serve as active-high transparent latch enables.

    Data flow in the B-to-A direction, regardless of the logic element selected, is further controlled by the LOOPBACK input. When LOOPBACK is low, B-port data is the B-to-A input. When SN74FB2033A LOOPBACK is high, the output of the selected A to-B logic element (prior to inversion) is the B-to-A input.

    The SN74FB2033A AO port-enable/-disable control is provided by OEA. When OEA is low or when V_CC is less than 2.5 V, the AO port is in the high-impedance state. When OEA is high, the AO port is active (high or low logic levels).

    The SN74FB2033A B port is controlled by OEB and  OEB. If OEB is low, OEB is high, or V_CC is less than 2.5 V, the B port is inactive. If  OEB is high and  OEB is low, the B port is active.

   SN74FB2033A  BG V_CC and BG GND are the bias-generator reference inputs.

    The SN74FB2033A A-to-B and B-to-A logic elements are active, regardless of the state of their associated outputs. The logic elements can enter new data (in flip-flop and latch modes) or retain previously stored data while the associated outputs are in the high-impedance (AO port) or inactive (B port) states.
    
    SN74FB2033A Output clamps are provided on the BTL outputs to reduce switching noise. One clamp reduces inductive ringing effects on V_OH during a low-to-high transition. The other clamps out ringing below the BTL V_OL voltage of 0.75 V. Both clamps are active only during ac switching and do not affect the BTL outputs during steady-state conditions.

    The SN74FB2033A is characterized for operation from 0°C to 70°C.