Texas Instruments SN74AVCH4T245RGYR

Overview

SN74AVCH4T245 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, bus-hold on all data inputs, and supports up to 380Mbps data rate (1.8V→3.3V). It is used in mixed-voltage system interconnects such as SoC-to-peripheral communication in portable electronics.

For engineers reviewing the SN74AVCH4T245 datasheet, SN74AVCH4T245 pinout, SN74AVCH4T245 application, or SN74AVCH4T245 equivalent, key selection criteria include dual-rail level-shifting capability, Ioff partial-power-down support, 3-state output control per channel, bus-hold elimination of external resistors, and VQFN-16 (RGY) package thermal performance (RθJA = 68.8°C/W).

Technical Context

The SN74AVCH4T245 implements a fully configurable dual-rail architecture where A-port I/Os and control pins (1DIR, 2DIR, 1OE, 2OE) are referenced to VCCA, while B-port I/Os track VCCB - enabling asynchronous bidirectional translation without direction latching. Its logic-level thresholds (VIH/VIL) scale with VCCA, ensuring robust operation across supply combinations.

Each of the two 2-bit sections operates independently: DIR controls data flow direction (A↔B), OE places corresponding outputs in high-impedance state, and bus-hold circuitry maintains valid logic states on undriven inputs. The device enters full high-Z when either VCCA or VCCB falls below ~0.4V, preventing false signaling during power sequencing.

Key Specifications

Pinout & Package

SN74AVCH4T245RGYR is packaged in a 4mm × 3.5mm VQFN-16 (RGY) with exposed thermal pad, optimized for low-inductance routing and efficient heat dissipation (RθJA = 68.8°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional level-shifting applications.

Compared with SN74LVC4T245RTER and TXB0104RGYR, the SN74AVCH4T245RGYR uniquely delivers independent dual-rail control, Ioff-enabled safe power-down, and integrated bus-hold - making it optimal for complex, multi-voltage, hot-pluggable embedded systems requiring deterministic behavior under fault conditions.

Availability

SN74AVCH4T245RGYR is available at Aetrix Electronics and suitable for mobile baseband interfaces, industrial PLC I/O modules, enterprise SSD controllers, and telecom FPGA interconnects requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74AVCH4T245RGYR 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 logic, interface, and power management technologies.

The SN74AVCH4T245 belongs to TI's AVC family of advanced voltage-translating transceivers, designed specifically for low-voltage, high-speed bidirectional communication between heterogeneous logic domains in portable, industrial, and communications equipment.

FAQ

What voltage ranges does the SN74AVCH4T245RGYR support on its A and B ports?

The SN74AVCH4T245RGYR supports VCCA and VCCB supply voltages independently from 1.2V to 3.6V. This allows translation between any standard low-voltage nodes - including 1.2V↔1.5V, 1.8V↔2.5V, 1.2V↔3.3V, and 1.8V↔3.3V - with guaranteed functionality across the full operating temperature range (–40°C to +85°C). Both rails must be within specification for normal operation.

How does the bus-hold feature on the SN74AVCH4T245RGYR eliminate external resistors?

The SN74AVCH4T245RGYR integrates active bus-hold circuitry on all eight data I/Os (1A1–2A2, 1B1–2B2), which sustains valid logic states (±25µA to ±100µA depending on VCCA) on undriven or floating inputs. This eliminates the need for external pull-up or pull-down resistors, reducing BOM cost, PCB area, and potential signal integrity degradation caused by resistor parasitics.

Can the SN74AVCH4T245RGYR operate with VCCA = 1.2V and VCCB = 3.3V simultaneously?

Yes, the SN74AVCH4T245RGYR is fully specified for simultaneous operation with VCCA = 1.2V and VCCB = 3.3V. In this configuration, it supports bidirectional translation at up to 100Mbps (per TI SCES577F Rev FEBRUARY 2025), with VOH ≥ 3.1V and VOL ≤ 0.3V on the B port, and VIH/VIL thresholds scaled to VCCA for reliable control input recognition.

What is the purpose of the Ioff feature in the SN74AVCH4T245RGYR?

The Ioff feature in the SN74AVCH4T245RGYR disables output drivers when either VCCA or VCCB is at 0V, limiting Ioff current to ±0.1µA max. This prevents damaging backflow current from a powered rail into a powered-down subsystem - a critical safety function in hot-swap, partial-power-down, or battery-backed systems where supply sequencing is uncontrolled.

Does the SN74AVCH4T245RGYR require external pull-up resistors on its OE pins?

Yes - to ensure the SN74AVCH4T245RGYR outputs remain in high-impedance state during power-up or power-down, TI recommends tying 1OE and 2OE to VCCA via pull-up resistors. The minimum resistance value depends on the current-sinking capability of the driving controller; typical values range from 4.7kΩ to 10kΩ for 3.3V VCCA, ensuring OE remains high until both VCCA and VCCB are stable.