These devices can be used as four 8-bit flip-flops, two 16-bit flip-flops, or one 32-bit flip-flop. On the positive transition of the clock (CLK), the Q outputs of the flip-flops take on the logic levels set up at the data (D) inputs. A buffered output-enable (OE) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines without interface or pullup components. OE does not affect internal operations of the flip-flop. Old data can be retained or new data can be entered while the outputs are in the high-impedance state. When VCC is between 0 and 1.2 V, the device is in the high-impedance state during power up or power down. However, to ensure the high-impedance state above 1.2 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. These devices are fully specified for hot-insertion applications using Ioff and power-up 3-state. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when they are powered down. The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down, which prevents driver conflict. Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level. The SN54ALVTH32374 is characterized for operation over the full military temperature range of 55C to 125C. The SN74ALVTH32374 is characterized for operation from 40C to 85C. |