7 Detailed Description

7.1 Overview

The SN74LVC2T45-Q1 is a dual-bit, dual-supply noninverting voltage level translation device. VCCA supports

pin Ax and the direction control pin, and VCCB supports pin Bx. The A port can 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 DIR allows data

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

7.2 Functional Block Diagram

B1

DIR

5

7

A1

2

VCCA

VCCB

B2

6

A2

3

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

SN74LVC2T45-Q1 can support high data rate applications. The translated signal data rate can be up to

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

7.3.3 Ioff Supports Partial-Power-Down Mode Operation

Ioff will prevent backflow current by disabling I/O output circuits when the device is in Partial-Power-Down mode.

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 Characteristics.

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

SN74LVC2T45-Q1

SCES818C – SEPTEMBER 2010 – REVISED JULY 2024

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