18-bit universal bus transceivers with 3-state outputs

These 18-bit universal bus transceivers combine D-type latches and D-type flip-flops to allow data flow in transparent, latched, and clocked modes.

Data flow in each direction is controlled by output-enable (OEAB\ and OEBA\), latch-enable (LEAB and LEBA), and clock (CLKAB and CLKBA) inputs. The clock can be controlled by the clock-enable (CLKENAB\ and CLKENBA\) inputs.

For A-to-B data flow, the device operates in the transparent mode when LEAB is high. When LEAB is low, the A data is latched if CLKAB is held at a high or low logic level. If LEAB is low, the A data is stored in the latch/flip-flop on the low-to-high transition of CLKAB. Output-enable OEAB\ is active-low. When OEAB\ is low, the outputs are active. When OEAB\ is high, the outputs are in the high-impedance state. Data flow for B to A is similar to that of A to B but uses OEBA\, LEBA, CLKBA, and CLKENBA\.

The B-port outputs, which are designed to source or sink up to 12 mA, include equivalent 25- series resistors to reduce overshoot and undershoot.

When VCC is between 0 and 2.1 V, the device is in the high-impedance state during power up or power down. However, to ensure the high-impedance state above 2.1 V, OE\ should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The SN54ABT162601 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT162601 is characterized for operation from -40°C to 85°C.