1 Features

• Control inputs (DIR and OE) VIH and VIL levels are

referenced to VCCA voltage

• Bus hold on data inputs eliminates the need for

external pullup or pulldown resistors

• VCC isolation feature

• Fully configurable dual-rail design

• I/Os are 4.6-V tolerant

• Ioff supports partial-power-down mode operation

• Maximum data rates:

– 320Mbps (VCCA ≥ 1.8V and VCCB ≥ 1.8V)

– 170Mbps (VCCA ≤ 1.8V or VCCB ≤ 1.8V)

• Latch-up performance exceeds 100mA per JESD

78, class II

• ESD protection exceeds JESD 22:

– 8000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

2 Applications

• Personal electronics

• Industrial

• Enterprise

• Telecommunications

3 Description

The SN74AVCH8T245 is an 8-bit noninverting bus

transceiver that uses two separate configurable

power-supply rails. The A port is designed to track

VCCA, which accepts any supply voltage from 1.2V

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

also accepts any supply voltage from 1.2V to 3.6V.

This allows for universal low-voltage bidirectional

translation between any of the 1.2-V, 1.5-V, 1.8-V, 2.5-

V, and 3.3-V voltage nodes.

The SN74AVCH8T245 is designed for asynchronous

communication between data buses. The device

transmits data from either the A bus to the B bus, or

from the B bus to the A bus, depending on the logic

level at the direction-control (DIR) input. The outputenable

(OE) input can be used to disable the outputs

so the buses are effectively isolated.

The design of SN74AVCH8T245 references the

control pins (DIR and OE) to VCCA.

Active bus-hold circuitry holds unused or undriven

inputs at a valid logic state. It is not recommended

to use pullup or pulldown resistors with the bus-hold

circuitry.

This device is fully specified for partial-power-down

applications using Ioff. The Ioff circuitry disables

the outputs, preventing damaging current backflow

through the device.

The VCC isolation feature allows the outputs to be in

the high-impedance state when either VCCA or VCCB

is at GND. The bus-hold circuitry on the powered-up

side always stays active.

The SN74AVCH8T245 solution is compatible with a

single-supply system and can be replaced later with

a '245 function, with minimal printed circuit board

redesign.

To put the device in the high-impedance state during

power up or power down, OE must be tied to VCCA

through a pullup resistor; the current-sinking capability

of the driver determines the minimum value of the

resistor.