7 Detailed Description

7.1 Overview

The SN74LVC1T45 is a single-bit, dual-supply, noninverting voltage level transceiver. Pin A and the direction

control pin (DIR) are supported by VCCA and pin B is supported by VCCB. The A port is able to accept I/O

voltages ranging from 1.65V to 5.5V, while the B port can accept I/O voltages from 1.65V to 5.5V. The high on

the DIR allows data transmissions from A to B and a low on the DIR allows data transmissions from B to A.

7.2 Functional Block Diagram

B

DIR

5

4

A

3

VCCA

VCCB

Figure 7-1. Logic Diagram (Positive Logic)

7.3 Feature Description

7.3.1 Fully Configurable Dual-Rail Design Allows Each Port to Operate Over the Full 1.65V to 5.5V

Power-Supply Range

Both VCCA and VCCB can be supplied at any voltage between 1.65V and 5.5V, making the device suitable for

translating between any of the voltage nodes (1.8V, 2.5V, 3.3V, and 5V).

7.3.2 Support High Speed Translation

The SN74LVC1T45 device supports high data rate applications. The translated signal data rate can be up to

420Mbps when the signal is translated from 3.3V to 5V.

7.3.3 Ioff Supports Partial Power-Down Mode Operation

The inputs and outputs for this device enter a high-impedance state when the device is powered down, inhibiting

current backflow into the device. The maximum leakage into or out of any input or output pin on the device is

specified by Ioff in the Electrical Charateristics.

7.3.4 Balanced High-Drive CMOS Push-Pull Outputs

A balanced output allows the device to sink and source similar currents. The high drive capability of this device

creates fast edges into light loads so impedance matching and load conditions should be considered to prevent

ringing. Additionally, the outputs of this device are capable of driving larger currents than the device can sustain

without being damaged. Two outputs can be connected together for a stronger output drive strength. The

electrical and thermal limits defined in the Absolute Maximum Ratings must be followed at all times.

7.3.5 Glitch-Free Power Supply Sequencing

Either supply rail may be powered on or off in any order without producing a glitch on the I/Os (that is, where

the output erroneously transitions to VCC when it should be held low or vice versa). Glitches of this nature can

be misinterpreted by a peripheral as a valid data bit, which could trigger a false device reset of the peripheral, a

false device configuration of the peripheral, or even a false data initialization by the peripheral.

www.ti.com

SN74LVC1T45

SCES515N – DECEMBER 2003 – REVISED JUNE 2024

Copyright © 2024 Texas Instruments Incorporated

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