Texas Instruments SN74AVC1T45DRLRG4

Overview

SN74AVC1T45 from Texas Instruments is a single-bit dual-supply bus transceiver enabling bidirectional voltage-level translation between 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V 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 for 1.8V→3.3V translation. It is used in low-voltage interconnects between SoCs and peripherals in portable electronics.

For engineers reviewing the SN74AVC1T45 datasheet, SN74AVC1T45 pinout, SN74AVC1T45 application, or SN74AVC1T45 equivalent, key selection criteria include dual-rail supply flexibility, VCC isolation behavior, Ioff-enabled partial-power-down support, DIR-input referencing to VCCA, and SOT-5X3 (DRL) package compatibility with high-density PCB layouts.

Technical Context

The SN74AVC1T45 implements a noninverting, direction-controlled bus transceiver architecture where DIR input-referenced solely to VCCA-gates signal flow between A and B ports. Each port tracks its dedicated supply rail, enabling asynchronous translation without shared reference constraints.

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 2.2ns (A→B, VCCA=3.3V/VCCB=2.5V) to 6.9ns (DIR→A, VCCA=1.5V/VCCB=3.3V), supporting timing-critical interfaces up to 500Mbps.

Key Specifications

Pinout & Package

The SN74AVC1T45 is packaged in a 6-pin SOT-5X3 (DRL) package measuring 1.6mm × 1.6mm, optimized for space-constrained portable designs. Its NanoFree™ construction uses the die as the package, eliminating bond wires and reducing parasitic inductance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXS0101DRLR and SN74LVC1T45DRLR, the SN74AVC1T45 uniquely delivers configurable dual-rail operation with VCC isolation and 4.6V I/O tolerance - essential for robust, mixed-voltage embedded systems requiring guaranteed high-Z behavior during power transitions.

Availability

SN74AVC1T45 is available at Aetrix Electronics and suitable for mobile processor interconnect, industrial sensor hub, enterprise SSD controller, and telecom baseband module applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, personal electronics, and communications markets.

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- and power-constrained portable and IoT devices.

FAQ

What is the minimum operating voltage for SN74AVC1T45 on each supply rail?

The SN74AVC1T45 supports VCCA and VCCB independently from 1.2V to 3.6V. Both rails may operate at 1.2V simultaneously, enabling translation between two 1.2V domains. Operation below 1.2V is not characterized or guaranteed - attempting to power either rail below this threshold risks undefined logic behavior and increased ICCZ leakage.

How does the VCC isolation feature behave when VCCA = 0V and VCCB = 3.3V?

When VCCA = 0V (GND), the SN74AVC1T45 forces both A and B ports into high-impedance state regardless of VCCB voltage or DIR input state. This prevents back-driving of the A port and eliminates contention on the B bus. The same behavior occurs if VCCB = 0V while VCCA is active - confirming true bidirectional rail isolation per JESD78 Class II latch-up immunity requirements.

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

No. While the SN74AVC1T45 I/O pins tolerate up to 4.6V, its output swing is strictly limited to the VCCB (for B port) or VCCA (for A port) supply voltage. Driving a true 5V load requires an external buffer or a different device such as the TXB0104. Using SN74AVC1T45 with a 5V pullup will result in ~3.3V high-level output when VCCB = 3.3V - insufficient for TTL or 5V CMOS input thresholds.

Is a pullup or pulldown resistor required on the DIR pin of SN74AVC1T45?

Yes. The DIR input has no internal pullup or pulldown; it must be actively driven to a valid logic HIGH or LOW referenced to VCCA. Leaving DIR floating causes undefined direction control, leading to bus contention or excessive ICC. A 10kΩ pullup to VCCA is recommended for default-A→B operation; a pulldown achieves default-B→A behavior.

What thermal derating applies to SN74AVC1T45 in the DRL (SOT-5X3) package at 85°C ambient?

In the DRL package, SN74AVC1T45 has RθJA = 236.2°C/W. At TA = 85°C and maximum power dissipation (Pd ≈ 15mW), junction temperature rise is ΔTj = Pd × RθJA ≈ 3.5°C - well within the 150°C absolute max rating. No derating is required up to 85°C ambient; however, sustained 500Mbps operation at 3.3V should verify local board copper area meets TI's recommended 25mm² thermal pad layout.