SN74LVCH8T245PW.B中文资料德州仪器数据手册PDF规格书

1 Features

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

referenced to VCCA

• Bus hold on data inputs eliminates the need for

external pullup and pulldown resistors

• VCC isolation

• Fully configurable dual-rail design

• Ioff supports Partial-Power-Down node operation

• Latch-up performance exceeds 100 mA per JESD

78, class II

• ESD protection exceeds JESD 22

2 Applications

• Personal electronics

• Industrial

• Enterprise

• Telecommunications

3 Description

The SN74LVCH8T245 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 1.65 V

to 5.5 V. The B port is designed to track VCCB, which

also accepts any supply voltage from 1.65 V to 5.5

V. This allows for universal low-voltage bidirectional

translation between any of the 1.8-V, 2.5-V, 3.3-V, and

5.5-V voltage nodes.

The SN74LVCH8T245 is designed for asynchronous

communication between two data buses. The logic

levels of the direction-control (DIR) input and the

output-enable (OE) input activate either the B-port

outputs, the A-port outputs, or place both output ports

into a high-impedance state. The device transmits

data from the A bus to the B bus when the B-port

outputs are activated, and from the B bus to the A

bus when the A-port outputs are activated. The input

circuitry on both A and B ports are always active.

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. 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 ensures that if either VCCA or VCCB is

at GND, then the outputs are in the high-impedance

state. To ensure the high-impedance state during

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

through a pullup resistor; the minimum value of the

resistor is determined by the current-sinking capability

of the driver.

The SN74LVCH8T245 is designed so that the control

pins (DIR and OE) are referenced to VCCA.