SN74AXC1T45/SN74AXC1T45-Q1 Bus Transceivers Texas Instruments SN74AXC1T45/SN74AXC1T45-Q1 Single-Bit Dual-Supply Bus Transceivers use two single configurable power-supply rails and are operational using both VCCA and VCCB supplies. The A port tracks VCCA, and the B port tracks VCCB, both accepting supply voltages from 0.65V to 3.6V. The DIR pin determines the direction of signal propagation. When the DIR pin is configured in HIGH mode, translation is from Port A to Port B. Translation is from Port B to Port A when configured in LOW mode. The DIR pin tracks logic-high and logic-low thresholds with VCCA.