Texas Instruments SN74AVC4T245DYYR

Overview

SN74AVC4T245 from Texas Instruments is a 4-bit dual-supply noninverting 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, 4.6V I/O tolerance, Ioff partial-power-down support, and up to 380Mbps data rate (1.8V→3.3V). It serves as a level-shifting interface in mixed-voltage SoC-to-peripheral communication.

For engineers reviewing the SN74AVC4T245 datasheet, SN74AVC4T245 pinout, SN74AVC4T245 application, or SN74AVC4T245 equivalent, key selection criteria include dual-rail configurability, 3-state output control per channel, VCCA-referenced DIR/OE inputs, thermal performance in SOT-16 (DYY), and compatibility with low-voltage industrial and embedded interconnects requiring robust isolation during power sequencing.

Technical Context

The SN74AVC4T245 implements two independent 2-bit bidirectional channels, each with dedicated DIR and OE controls referenced to VCCA. Its dual-rail architecture decouples A-port (VCCA-tracked) and B-port (VCCB-tracked) logic thresholds, enabling asynchronous translation without clocking or direction latching.

Functional modes are defined by OE (global 3-state enable) and DIR (per-channel direction select): OE = L + DIR = L enables B→A data flow; OE = L + DIR = H enables A→B; OE = H forces both ports into high-impedance regardless of DIR. Ioff circuitry disables outputs when either VCCA or VCCB = 0V, preventing backflow current.

Key Specifications

Pinout & Package

SN74AVC4T245DYYR uses a 16-pin SOT package (4.2mm × 2.0mm), optimized for space-constrained PCB layouts in portable and IoT edge devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC4T245PWR and TXS0104EPWR, the SN74AVC4T245 provides wider voltage range (1.2–3.6V), higher speed (380Mbps), and essential Ioff/VCC isolation for modern low-power, mixed-voltage system architectures - making it the optimal choice for demanding industrial, automotive, and portable designs.

Availability

SN74AVC4T245DYYR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, portable device memory interface, automotive infotainment gateways, and enterprise SSD controller bridges requiring stable component supply across extended temperature and mixed-voltage environments.

Supply support for SN74AVC4T245DYYR 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 for industrial, automotive, personal electronics, and enterprise applications.

The SN74AVC4T245 belongs to TI's AVC (Advanced Very-Low-Voltage CMOS) logic family, designed specifically for high-speed, low-voltage bidirectional level translation in next-generation mixed-signal systems with aggressive power and space constraints.

FAQ

What voltage ranges does the SN74AVC4T245 support on its A and B ports?

The SN74AVC4T245 supports independent 1.2V to 3.6V operation on both VCCA (A-port supply) and VCCB (B-port supply). This enables translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. The SN74AVC4T245 datasheet specifies absolute maximum ratings up to 4.6V on all I/O pins, ensuring robustness against overvoltage transients during system integration.

How does the SN74AVC4T245 handle power sequencing when VCCA and VCCB ramp at different rates?

The SN74AVC4T245 incorporates VCC isolation: if either VCCA or VCCB is at GND, both A and B ports automatically enter high-impedance mode. This prevents false signaling or latch-up during asymmetric power-up/down. For reliable operation, OE should be tied to VCCA via a pullup resistor to ensure outputs remain disabled until both supplies stabilize - a behavior explicitly validated in the SN74AVC4T245 design guidelines.

Can the SN74AVC4T245 replace the SN74LVC4T245 in an existing design?

The SN74AVC4T245 is not a drop-in replacement for the SN74LVC4T245 due to fundamental architectural differences: SN74AVC4T245 requires dual supplies (VCCA/VCCB) and has VCCA-referenced controls, whereas SN74LVC4T245 uses a single supply. Direct substitution would require PCB modifications to separate power rails and re-route OE/DIR references. The SN74AVC4T245 offers superior voltage flexibility and Ioff but demands updated layout and power architecture.

What is the maximum data rate achievable with the SN74AVC4T245, and under what conditions?

The SN74AVC4T245 achieves a maximum data rate of 380Mbps when translating from 1.8V to 3.3V (VCCA = 1.8V, VCCB = 3.3V), as specified in the official SN74AVC4T245 datasheet. Performance degrades at lower voltage combinations: 200Mbps for <1.8V→3.3V or ↔2.5V/1.8V, 150Mbps for ↔1.5V, and 100Mbps for ↔1.2V. These values reflect guaranteed AC switching characteristics under recommended operating conditions.

Does the SN74AVC4T245 support hot-swap or partial-power-down operation?

Yes, the SN74AVC4T245 supports partial-power-down via its Ioff feature. When either VCCA or VCCB is at 0V, the Ioff circuitry disables all I/O outputs, limiting off-state current to ±1μA maximum and preventing damaging backflow current. This capability is explicitly tested per JESD78 Class II latch-up standards and is integral to the SN74AVC4T245's design for hot-plug, battery-backed, and energy-efficient subsystems.