Single-bit dual-supply bus transceiver

The SN74AXC1T45 is a single-bit noninverting bus transceiver that uses two

separate configurable power-supply rails. The device is operational with both

VCCA and VCCB supplies as low as 0.65 V. The A port is

designed to track VCCA, which accepts any supply voltage from 0.65 V to

3.6V. The B port is designed to track VCCB, which also accepts any

supply voltage from 0.65 V to 3.6V.

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 VCCA, meaning that its logic-high and logic-low

thresholds track with VCCA.

This device is fully specified for

partial-power-down applications using the Ioff current. The

Ioff 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 VCC isolation feature

ensures that if either VCCA or VCCB is less than 100mV, both

I/O ports enter a high-impedance state by disabling their outputs.

The glitch suppression circuitry

enables either supply rail to be powered on or off in any order, providing robust

power sequencing performance.