Texas Instruments 74LVCH8T245DWRG4

Overview

74LVCH8T245DWRG4 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 bus-hold on all data I/Os, VCCA-referenced DIR/OE controls, Ioff partial-power-down protection, and VCC isolation-used in industrial backplanes, smart meter interfaces, and video surveillance interconnects.

For engineers reviewing the 74LVCH8T245DWRG4 datasheet, 74LVCH8T245DWRG4 pinout, 74LVCH8T245DWRG4 application, or 74LVCH8T245DWRG4 equivalent, key selection criteria include configurable dual-rail operation, guaranteed glitch-free power sequencing, 3-state output timing (tPHZ ≤ 29.6 ns), ±32 mA drive strength at 5V, and compatibility with SSOP-24 packaging for legacy board layouts.

Technical Context

The 74LVCH8T245DWRG4 implements a fully asynchronous 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 level relative to VCCA, and 3-state output enable is governed solely by OE referenced to VCCA-not VCCB.

Its active bus-hold circuitry eliminates external pull resistors on undriven A/B pins, and VCC isolation ensures high-impedance outputs when either VCCA or VCCB falls below 100 mV or floats. Ioff leakage is limited to ±2 µA per port during partial-power-down, meeting JESD78 Class II latch-up immunity (>100 mA).

Key Specifications

Pinout & Package

74LVCH8T245DWRG4 is packaged in a 24-pin SSOP (DB) with dimensions 8.2 mm × 7.8 mm and standard 0.635 mm lead pitch. The package supports surface-mount reflow and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC8T245RHLR and TXS0108EJRGR, the 74LVCH8T245DWRG4 uniquely delivers SSOP-24 compatibility, explicit DIR control for deterministic parallel bus timing, and highest drive strength (±32 mA) among TI's 8-bit translators-making it optimal for industrial backplane and metering applications demanding layout continuity and robust signal integrity.

Availability

74LVCH8T245DWRG4 is available at Aetrix Electronics and suitable for industrial backplane interconnect, smart meter communication interface, and video surveillance data link applications requiring stable component supply across extended temperature and long product lifecycles.

Supply support for 74LVCH8T245DWRG4 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 specializing in analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The SN74LVCH8T245 product line delivers robust, dual-supply bus transceivers designed for voltage translation and interoperability across mixed-voltage systems in infrastructure and measurement equipment.

FAQ

What voltage ranges does the 74LVCH8T245DWRG4 support on its A and B ports?

The 74LVCH8T245DWRG4 supports independent supply voltages from 1.65V to 5.5V on both VCCA and VCCB. This allows reliable bidirectional level translation between common logic families-including 1.8V, 2.5V, 3.3V, and 5V domains-without external components. Each port's I/Os and associated bus-hold circuitry operate within their respective supply range, and control inputs (DIR, OE) are referenced exclusively to VCCA.

How does the VCC isolation feature function in the 74LVCH8T245DWRG4?

The VCC isolation feature in the 74LVCH8T245DWRG4 forces all A- and B-port outputs into a high-impedance state when either VCCA or VCCB falls below 100 mV or is left floating. This prevents bus contention during power-up, power-down, or fault conditions. The behavior is intrinsic to the silicon design and requires no external circuitry-ensuring safe operation in hot-swap or partial-power-down scenarios typical in smart meter and grid infrastructure systems.

Can the 74LVCH8T245DWRG4 replace the SN74LVC8T245 in existing SSOP-24 designs?

Yes-the 74LVCH8T245DWRG4 is pin-compatible and functionally equivalent to SN74LVC8T245 in SSOP-24 packaging. Both share identical pinout, electrical specifications, and functional modes. The 'H' suffix denotes enhanced bus-hold strength and improved Ioff performance, making 74LVCH8T245DWRG4 a direct upgrade path with no PCB or firmware changes required for most industrial applications.

What is the maximum data rate supported by the 74LVCH8T245DWRG4 in a 3.3V-to-5V translation setup?

In a 3.3V-to-5V configuration (VCCA = 3.3V, VCCB = 5V), the 74LVCH8T245DWRG4 achieves tPLH/tPHL ≤ 6.2 ns and tPHZ/tPLZ ≤ 8.2 ns. These timings support reliable operation up to ~80 MHz for parallel data buses under typical load conditions (CL ≤ 15 pF). For sustained high-speed use, layout best practices-including matched trace lengths and local decoupling-are recommended to maintain signal integrity.

Does the 74LVCH8T245DWRG4 require external pull-up resistors on its data lines?

No-external pull-up or pull-down resistors are not required on A1–A8 or B1–B8 due to integrated active bus-hold circuitry. This feature maintains valid logic states on undriven or floating inputs, reducing BOM count and PCB area. Adding external resistors defeats the bus-hold function and may cause contention or increased power consumption, so TI explicitly advises against their use with the 74LVCH8T245DWRG4.