ET74AVCH4T245

General Description

The ET74AVCH4T245 is an 4-bit, dual supply transceiver that enables bidirectional level translation. It features two 4-bit input-output ports (nAn and nBn), a direction control input (DIR), an output enable input () and dual supply pins (VCC(A) and VCC(B)). Both VCC(A) and VCC(B) can be supplied at any voltage between 0.8V and 3.6V making the device suitable for translating between any of the low voltage nodes (0.8V, 1.2V, 1.8V and 3.3V). Pins nAn, OE and DIR are referenced to VCC(A) and pins nBn are referenced to VCC(B). A HIGH on DIR allows transmission from nAn to nBn and a LOW on DIR allows transmission from nBn to nAn. The output enable input () can be used to disable the outputs so the buses are effectively isolated. The device is fully specified for partial power-down applications using IOFF. The IOFF circuitry disables the output, preventing any damaging backflow current through the device when it is powered down. In suspend mode when either VCC(A) or VCC(B) are at GND level, both An and Bn outputs are in the high-impedance OFF-state. The bus-hold circuitry on the powered-up side always stays active. The ET74AVCH4T245 has active bus hold circuitry which is provided to hold unused or floating data inputs at a valid logic level. This feature eliminates the need for external pull-up or pull-down resistors.