Texas Instruments SN74AXCH1T45DRYR

The SN74AXCH1T45 is a single-bit noninverting bus transceiver that uses two individually configurable power-supply rails. The device is operational with both V_CCA and V_CCB supplies as low as 0.65 V. The A port is designed to track V_CCA, which accepts any supply voltage from 0.65 V to 3.6 V. The B port is designed to track V_CCB, which also accepts any supply voltage from 0.65 V to 3.6 V. Additionally the SN74AXCH1T45 is compatible with a single-supply system.

The DIR pin determines the direction of signal propagation. With the DIR pin configured HIGH, translation is from Port A to Port B. With DIR configured LOW, translation is from Port B to Port A. The DIR pin is referenced to V_CCA, meaning that its logic-high and logic-low thresholds track with V_CCA.

Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended. If a supply is present for V_CCA or V_CCB, the bus-hold circuitry always remains active on the A or B inputs respectively, independent of the state of the direction control pin.

This device is fully specified for partial-power-down applications using the I_off current. The I_off protection circuitry ensures that no excessive current is drawn from or to an input, output, or combined I/O that is biased to a specific voltage while the device is powered down.

The V_CC isolation feature ensures that if either V_CCA or V_CCB is less than 100 mV, both I/O ports enter a high-impedance state by disabling their outputs.

Glitch-free power supply sequencing allows either supply rail to be powered on or off in any order while providing robust power sequencing performance.