Texas Instruments 74LVCH8T245NSRG4

Overview

74LVCH8T245NSRG4 from Texas Instruments is an 8-bit dual-supply noninverting bus transceiver enabling bidirectional voltage-level translation between 1.65V–5.5V domains (e.g., 1.8V ↔ 3.3V, 3.3V ↔ 5V). It features independent VCCA and VCCB rails, bus-hold on all data I/Os, Ioff partial-power-down protection, and VCC isolation-used in industrial communication interfaces requiring robust supply sequencing and glitch-free operation.

For engineers reviewing the 74LVCH8T245NSRG4 datasheet, 74LVCH8T245NSRG4 pinout, 74LVCH8T245NSRG4 application, or 74LVCH8T245NSRG4 equivalent, key selection criteria include dual-rail level-shifting capability, 3-state control referenced to VCCA, bus-hold elimination of external resistors, and compatibility with mixed-voltage system interconnects in wired networking and smart metering.

Technical Context

The device implements a fully configurable dual-rail architecture where A-port I/Os and control inputs (DIR, OE) are referenced to VCCA (1.65V–5.5V), while B-port I/Os track VCCB (1.65V–5.5V). Directional data flow is controlled by DIR: high enables A→B transmission, low enables B→A transmission.

Glitch-free power sequencing ensures safe operation during asymmetric power-up/down of VCCA and VCCB. The VCC isolation feature forces all outputs into high-impedance when either supply drops below 100 mV or floats, and Ioff limits backflow current during partial-power-down states.

Key Specifications

Pinout & Package

74LVCH8T245NSRG4 is packaged in a 24-pin SSOP (DB) package measuring 8.2 mm × 7.8 mm, with gull-wing leads and 0.635 mm pitch. Pin assignment follows TI's standard DB footprint for 24-pin transceivers.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC8T245RHLR and TXB0108PWR, the 74LVCH8T245NSRG4 provides guaranteed 5V-tolerant I/Os, explicit DIR control for deterministic bidirectional protocols, and SSOP packaging optimized for automated optical inspection and rework accessibility in industrial assembly.

Availability

74LVCH8T245NSRG4 is available at Aetrix Electronics and suitable for industrial smart metering, wired networking infrastructure, medical diagnostic equipment, and grid monitoring systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for 74LVCH8T245NSRG4 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, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74LVCH8T245 product line delivers robust, dual-rail level-shifting transceivers designed for mixed-voltage system interconnects in harsh environments where supply sequencing integrity and I/O protection are critical.

FAQ

What voltage ranges does the 74LVCH8T245NSRG4 support on its A and B ports?

The 74LVCH8T245NSRG4 supports 1.65V to 5.5V on both VCCA and VCCB rails independently. This allows it to translate between any pair of common logic voltages-including 1.8V ↔ 2.5V, 2.5V ↔ 3.3V, 3.3V ↔ 5V, and 1.8V ↔ 5V-without external components. Each port's I/Os and associated control signals are referenced strictly to their respective supply, ensuring correct threshold tracking across the full range.

How does the 74LVCH8T245NSRG4 handle power sequencing when VCCA and VCCB are powered up at different times?

The 74LVCH8T245NSRG4 guarantees glitch-free operation during asymmetric power sequencing: either VCCA or VCCB may be applied or removed in any order without causing spurious output transitions. Its internal design prevents false logic states on A/B I/Os during ramp-up or brown-out, avoiding miscommunication with connected peripherals-a key requirement in modular power architectures used in smart meters and grid equipment.

Does the 74LVCH8T245NSRG4 require external pullup or pulldown resistors on its data lines?

No, the 74LVCH8T245NSRG4 integrates active bus-hold circuitry on all A1–A8 and B1–B8 I/Os. This feature maintains undriven or floating inputs at valid logic levels, eliminating the need for external pullup or pulldown resistors. Using external resistors with enabled bus-hold is not recommended, as it degrades noise margin and defeats the purpose of the integrated function.

What is the role of the DIR and OE pins, and how are they referenced?

DIR (direction control) and OE (output enable) are both referenced to VCCA-not VCCB. DIR high enables data flow from A to B; DIR low enables B to A. OE low enables transceiver operation; OE high places all A and B outputs in high-impedance state. Because both control inputs track VCCA, their VIH/VIL thresholds scale with VCCA voltage, ensuring reliable operation across the full 1.65V–5.5V supply range.

Can the 74LVCH8T245NSRG4 be used in partial-power-down applications?

Yes-the 74LVCH8T245NSRG4 includes Ioff circuitry that disables outputs and limits leakage current to ±2 μA when either VCCA or VCCB is at 0 V. This prevents damaging back-current flow through powered-down sections of a system, making it suitable for subsystem power gating in battery-operated or energy-efficient designs such as portable medical monitors and remote telemetry units.