Texas Instruments SN74AVCH4T245D

Overview

SN74AVCH4T245D 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 system interconnects such as SoC-to-peripheral communication in portable electronics.

For engineers reviewing the SN74AVCH4T245D datasheet, SN74AVCH4T245D pinout, SN74AVCH4T245D application, or SN74AVCH4T245D equivalent, key selection criteria include configurable dual-rail operation, 380Mbps max data rate (1.8V→3.3V), 16-pin SOIC package compatibility, 3-state output control via DIR/OE, and VCC isolation behavior during power sequencing.

Technical Context

The SN74AVCH4T245D implements asynchronous bidirectional level translation using two independent supply domains: A-port I/Os and control inputs (DIR, OE) are referenced to VCCA; B-port I/Os are referenced to VCCB. Direction is controlled per 2-bit channel by dedicated DIR pins, while OE enables/disables outputs independently for each channel.

Its logic-level translation relies on input thresholds tied to VCCA (VIH/VIL = VCCA × 0.65/0.35 in 1.2–1.95V range), ensuring robust switching across supply combinations. The device enters high-impedance state when either VCCA or VCCB falls below ~0.4V (VCC isolation), and supports hot-insertion via Ioff current limiting (<5µA at 0V supply).

Key Specifications

Pinout & Package

SN74AVCH4T245D uses a 16-pin SOIC (D) package measuring 9.9mm × 6mm, with standard 1.27mm pitch and gull-wing leads. Pin 1 is marked with a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC4T245D and TXS0104ED, the SN74AVCH4T245D uniquely supports true dual-rail independence, VCC isolation, and Ioff-making it the only option among the three for robust mixed-voltage system interconnects with dynamic power sequencing.

Availability

SN74AVCH4T245D is available at Aetrix Electronics and suitable for mobile device interface bridges, industrial sensor hubs, enterprise SSD controller links, and telecom baseband interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74AVCH4T245D 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 leader delivering analog and embedded processing solutions for industrial, automotive, personal electronics, and communications markets.

The SN74AVCH4T245D belongs to TI's AVC logic family, designed specifically for low-voltage bidirectional level translation in power-constrained, mixed-supply systems where supply sequencing, bus integrity, and ESD robustness are critical.

FAQ

What voltage ranges does the SN74AVCH4T245D support on its A and B ports?

The SN74AVCH4T245D supports 1.2V to 3.6V on both VCCA (A-port supply) and VCCB (B-port supply), enabling translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V logic domains. Input thresholds scale with VCCA, and B-port I/Os tolerate up to 4.6V regardless of VCCB setting. This flexibility makes the SN74AVCH4T245D ideal for heterogeneous voltage system integration.

How does the SN74AVCH4T245D handle power sequencing when VCCA and VCCB ramp at different times?

The SN74AVCH4T245D incorporates VCC isolation: if either VCCA or VCCB falls below ~0.4V, both A and B ports automatically enter high-impedance state. This prevents false logic levels or back-driving during asymmetric power-up/down. Additionally, Ioff limits leakage to <0.1µA when one supply is off, protecting powered subsystems. These features make the SN74AVCH4T245D robust in real-world power sequencing scenarios.

Does the SN74AVCH4T245D require external pull-up or pull-down resistors on its data lines?

No, the SN74AVCH4T245D includes active bus-hold circuitry on all A- and B-port I/Os, which maintains valid logic states on undriven or floating inputs. TI explicitly advises against using external pull resistors with bus-hold enabled, as they interfere with the internal sustaining current (±25µA to ±100µA). This eliminates BOM items and routing overhead, simplifying design for the SN74AVCH4T245D in space-constrained applications.

What is the maximum data rate supported by the SN74AVCH4T245D, and under what conditions?

The SN74AVCH4T245D supports up to 380Mbps when translating from 1.8V (VCCA) to 3.3V (VCCB), with typical propagation delays as low as 2.6ns. Performance degrades slightly at lower voltage combinations: 200Mbps for <1.8V→3.3V or translation to 2.5V/1.8V, 150Mbps to 1.5V, and 100Mbps to 1.2V. These values are measured under recommended operating conditions and reflect actual achievable throughput in properly terminated systems using the SN74AVCH4T245D.

Can the SN74AVCH4T245D be used in hot-swap or partial-power-down applications?

Yes, the SN74AVCH4T245D is explicitly designed for partial-power-down operation via its Ioff feature. When either VCCA or VCCB is at 0V, the Ioff circuitry disables output drivers, limiting leakage current to ±0.1µA typical. This prevents damaging back-current into powered rails and ensures safe hot-swap capability. The VCC isolation feature further guarantees high-impedance state during power transitions, making the SN74AVCH4T245D suitable for modular, field-replaceable systems.