●The SN54LVC646A octal bus transceiver and register is designed for 2.7-V to 3.6-V VCC operation, and the SN74LVC646A octal bus transceiver and register is designed for 1.65-V to 3.6-V VCC operation.
●These devices consist of bus-transceiver circuits, 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 is clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental bus-management functions that are performed with the LVC646A devices.
●Output-enable (OE)\ and direction-control (DIR) inputs control the transceiver functions. In the transceiver mode, data present at thehigh-impedance port is stored in either register or in both.
●The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. DIR determines which bus receives data when OE\ is low. In the isolation mode (OE\ high), A data is stored in one register and B data can be stored in the other register.
●When an output function is disabled, the input function is still enabled and can be used to store and transmit data. Only one of the two buses, A or B, can be driven at a time.
●Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of these devices as translators in a mixed 3.3-V/5-V system environment.
●These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.
●To ensure the high-impedance state during power up or power down, 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.
● Operate From 1.65 V to 3.6 V
● Inputs Accept Voltages to 5.5 V
● Max tpd of 7.4 ns at 3.3 V
● Typical VOLP(Output Ground Bounce)
● <0.8 V at VCC = 3.3 V, TA = 25°C
● Typical VOHV (Output VOH Undershoot)
● >2 V at VCC = 3.3 V, TA = 25°C
● Supports Mixed-Mode Signal Operation on All Ports (5-V Input/Output Voltage With 3.3-V VCC)
● Ioff Supports Partial-Power-Down Mode Operation
● Latch-Up Performance Exceeds 250 mA Per JESD 17
● ESD Protection Exceeds JESD 22
● 2000-V Human-Body Model (A114-A)
● 200-V Machine Model (A115-A)
● 1000-V Charged-Device Model (C101)
