Texas Instruments SN74AVC1T45DBVT

Overview

SN74AVC1T45 from Texas Instruments is a single-bit dual-supply bus transceiver enabling bidirectional voltage translation between 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. It features independent VCCA (1.2–3.6V) and VCCB (1.2–3.6V) rails, ±12mA drive at 3.3V, 4.6V I/O tolerance, and 500Mbps max data rate (1.8V→3.3V), used in low-voltage interconnects between SoCs and peripherals.

For engineers reviewing the SN74AVC1T45 datasheet, SN74AVC1T45 pinout, SN74AVC1T45 application, or SN74AVC1T45 equivalent, key selection criteria include dual-rail configurability, VCC isolation behavior, Ioff partial-power-down support, DIR-referenced control logic, and NanoFree™ SOT-23 package compatibility with high-density PCB layouts.

Technical Context

The SN74AVC1T45 implements asynchronous bidirectional level translation via a direction-controlled transceiver architecture: DIR referenced to VCCA enables A→B (DIR=H) or B→A (DIR=L) data flow. Both ports remain active regardless of DIR state, requiring defined logic levels on all I/Os to avoid excess ICC/ICCZ.

VCC isolation ensures both ports enter high-impedance when either VCCA or VCCB = GND; Ioff circuitry disables outputs during partial power-down to prevent backflow current. Propagation delays range from 2.4ns (A→B, VCCA=1.2V/VCCB=3.3V) to 6.9ns (DIR→A, VCCA=1.5V/VCCB=3.3V), with enable/disable times derived from cascaded switching parameters.

Key Specifications

Pinout & Package

SN74AVC1T45 DBVT uses the DBV (SOT-23-6) package: 2.9mm × 2.8mm footprint, 0.95mm height, lead pitch 0.95mm, compatible with standard pick-and-place and reflow processes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus transceiver applications.

Compared with TXB0101DBVR and SN74LVC1T45DBVR, the SN74AVC1T45 uniquely supports deterministic DIR-controlled bidirectional translation across the full 1.2V–3.6V range with VCC isolation - essential for power-sequenced systems and mixed-voltage SoC interconnects.

Availability

SN74AVC1T45 is available at Aetrix Electronics and suitable for mobile baseband interfaces, industrial sensor hubs, enterprise SSD controllers, and automotive infotainment gateways requiring stable component supply across extended temperature and mixed-voltage operating conditions.

Supply support for SN74AVC1T45 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company delivering analog and embedded processing solutions, with leadership in precision analog, power management, and interface technologies.

The SN74AVC1T45 belongs to TI's AVC (Advanced Very-Low-Voltage CMOS) logic family, designed specifically for ultra-low-voltage bidirectional level translation in space-constrained, multi-rail portable and industrial systems.

FAQ

What is the minimum operating voltage for SN74AVC1T45 on VCCA and VCCB?

The SN74AVC1T45 supports operation down to 1.2V on both VCCA and VCCB rails independently. This enables direct interfacing with advanced low-power processors and memory subsystems operating at 1.2V nominal supply, while maintaining full functionality including Ioff and VCC isolation features.

Does SN74AVC1T45 require external pull-up or pull-down resistors on the DIR pin?

Yes, the SN74AVC1T45 DIR input has no internal pull-up or pull-down. An external resistor (typically 10kΩ to VCCA or GND) is required to ensure a defined logic state during power-up, reset, or high-impedance control conditions - otherwise undefined DIR states may cause bus contention.

Can SN74AVC1T45 translate between 1.2V and 5V logic levels?

No. While the I/O pins tolerate up to 4.6V, SN74AVC1T45 is rated for VCCA and VCCB operation only between 1.2V and 3.6V. Applying 5V to VCCA or VCCB exceeds absolute maximum ratings and risks permanent damage; use a 5V-tolerant translator like SN74AVCH series for 5V interfaces.

How does VCC isolation behave during power sequencing in SN74AVC1T45?

When either VCCA or VCCB is driven to GND (0V), the SN74AVC1T45 automatically places both A and B ports into high-impedance state - preventing signal leakage, contention, or backdrive current during staggered power-up/down sequences common in multi-rail systems.

Is SN74AVC1T45 compatible with I²C or SMBus bidirectional protocols?

The SN74AVC1T45 supports bidirectional data flow but lacks built-in bus arbitration or slew-rate control required for standard I²C/SMBus compliance. It can be used for point-to-point level shifting in non-standard implementations where external pull-ups and timing margins accommodate its propagation delay and lack of open-drain emulation.