Texas Instruments SN74AVCH4T245DT

Overview

SN74AVCH4T245DT from Texas Instruments is a 4-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, 4.6V I/O tolerance, bus-hold circuitry, and Ioff partial-power-down support. It is used in mixed-voltage interconnects between processors and peripherals in portable electronics and industrial controllers.

For engineers reviewing the SN74AVCH4T245DT datasheet, SN74AVCH4T245DT pinout, SN74AVCH4T245DT application, or SN74AVCH4T245DT equivalent, key selection criteria include configurable dual-rail operation, 380Mbps max data rate (1.8V→3.3V), 3-state output control via DIR/OE, Ioff-enabled isolation, and SOIC-16 package compatibility with legacy 74-series footprints.

Technical Context

The SN74AVCH4T245DT implements a fully asynchronous, direction-controlled bidirectional translation architecture. Its two independent 2-bit sections each use separate DIR and OE inputs referenced to VCCA, allowing independent control of A↔B data flow per channel pair. The device operates without internal clocking or state machines - logic propagation is purely combinatorial and rail-to-rail.

VCC isolation ensures both ports enter high-impedance when either VCCA or VCCB falls below ~0.4V, preventing bus contention during power sequencing. Bus-hold circuitry actively maintains valid logic states on undriven A/B port inputs without external resistors, reducing BOM count and layout complexity in floating-bus scenarios.

Key Specifications

Pinout & Package

SN74AVCH4T245DT is packaged in a 16-pin SOIC (D package), 9.9mm × 6mm body size, with standard 1.27mm pitch. Pin 1 is VCCA; pins 8 and 9 are GND; pin 16 is VCCB. All control inputs (1DIR, 2DIR, 1OE, 2OE) and A-port I/Os (1A1–2A2) are VCCA-referenced; B-port I/Os (1B1–2B2) are VCCB-referenced.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC4T245PW and TXS0104EPWR, the SN74AVCH4T245DT uniquely supports independent 1.2–3.6V rails per port, delivers highest data rate (380Mbps), and provides push-pull drive on both sides - making it optimal for high-fidelity, mixed-voltage parallel bus interfaces requiring deterministic direction control.

Availability

SN74AVCH4T245DT is available at Aetrix Electronics and suitable for mobile processor interface, industrial PLC backplane, enterprise SSD controller, and telecom baseband FPGA interface applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74AVCH4T245DT 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 logic ICs.

The SN74AVCH4T245DT belongs to TI's AVC family of advanced voltage-translating logic devices, engineered specifically for robust, low-voltage bidirectional communication between heterogeneous SoCs, FPGAs, and peripheral ICs in portable and industrial systems.

FAQ

What voltage ranges does the SN74AVCH4T245DT support on its A and B ports?

The SN74AVCH4T245DT supports 1.2V to 3.6V independently on both VCCA (A port) and VCCB (B port). This enables translation between any pair of low-voltage nodes - including 1.2V↔1.5V, 1.8V↔2.5V, and 1.8V↔3.3V - without external components. Each port's I/Os are tolerant up to 4.6V regardless of rail voltage, enhancing system robustness.

How does the SN74AVCH4T245DT handle power sequencing when VCCA and VCCB ramp at different times?

The SN74AVCH4T245DT incorporates VCC isolation: if either VCCA or VCCB falls below ~0.4V, both A and B ports automatically enter high-impedance mode. This prevents false logic states or bus contention during asymmetric power-up/down. Additionally, Ioff limits backflow current to ±5µA when one rail is unpowered, supporting hot-swap and partial-power-down modes in the SN74AVCH4T245DT design.

Can the SN74AVCH4T245DT replace traditional 74-series transceivers like the 74LS245 in legacy designs?

Yes - the SN74AVCH4T245DT uses the same SOIC-16 (D) package and pinout as industry-standard 74-series transceivers, enabling drop-in replacement in many cases. However, unlike 74LS245, the SN74AVCH4T245DT requires dual supplies (VCCA/VCCB) and offers voltage translation, bus-hold, and Ioff. Designers must verify supply rail assignments and update OE/DIR logic levels to match VCCA referencing.

What is the maximum data rate supported by the SN74AVCH4T245DT, and under what conditions?

The SN74AVCH4T245DT supports up to 380Mbps, but only when translating from 1.8V to 3.3V (VCCA = 1.8V, VCCB = 3.3V). Rates decrease with lower-voltage combinations: 200Mbps for <1.8V→3.3V or 1.8V→2.5V, 150Mbps for 1.8V→1.5V, and 100Mbps for 1.2V→1.2V. These values are measured under specified load and transition conditions per TI's SCES577F datasheet for the SN74AVCH4T245DT.

Does the SN74AVCH4T245DT require external pull-up or pull-down resistors on its data lines?

No - the SN74AVCH4T245DT integrates active bus-hold circuitry on all A- and B-port inputs, which maintains valid logic states on undriven or floating lines without external resistors. TI explicitly advises against using pull-up/pull-down resistors with bus-hold enabled, as they may conflict with the internal sustaining current (±25µA to ±100µA). Unused inputs can be left floating safely in the SN74AVCH4T245DT implementation.