The SN74AXC1T45 of Texas Instruments is a unit non inverting bus transceiver, which uses two independent configurable power rails. The equipment can work under V (CCA) and V (CCB) power supply as low as 0.65 V. The A port is designed to track V (CCA) and accepts any supply voltage from 0.65 V to 3.6 V. The B port is designed to track V (CCB) and also accepts any supply voltage from 0.65 V to 3.6 V.
5 Pin Configuration
The DIR pin determines the direction of signal propagation. When the DIR pin is configured as high, switch from port A to port B; When DIR is configured as low, switch from port B to port A. The DIR pin references V (CCA), which means that its logic high threshold and logic low threshold track V (CCA).
Thermal Information
These devices are fully designated for partial power off applications using I (off) current. The I (off) protection circuit ensures that when the equipment is powered off, there is no excessive current from the bias to the input, output or combined I/O of specific voltage. The V (CC) isolation feature ensures that if V (CCA) or V (CCB) is less than 100 mV, the two I/O ports enter a high impedance state by disabling their outputs.
The fault free power supply sequence allows the power rail to be opened or closed in any order without data fault (i.e. the output waveform is temporarily switched from logic low level to logic high level).
Simplified Schematic
