Texas Instruments 74LVCH8T245DBQRG4

Overview

74LVCH8T245DBQRG4 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 I/Os, Ioff partial-power-down protection, and VCC isolation - deployed in industrial data buses requiring robust level-shifting without external resistors.

For engineers reviewing the 74LVCH8T245DBQRG4 datasheet, 74LVCH8T245DBQRG4 pinout, 74LVCH8T245DBQRG4 application, or 74LVCH8T245DBQRG4 equivalent, key selection criteria include dual-rail operating range (1.65V–5.5V per rail), guaranteed 32mA output drive at 5V, bus-hold current specs (±100μA), glitch-free power sequencing, and SSOP-24 package compatibility with 8.2mm × 7.8mm footprint.

Technical Context

The 74LVCH8T245DBQRG4 implements a fully configurable dual-rail architecture where A-port I/Os and control inputs (DIR, OE) reference VCCA, while B-port I/Os reference VCCB - enabling asynchronous bidirectional translation without direction-control timing constraints. Its logic-level translation is decoupled from supply sequencing order, eliminating glitches during power-up/down transitions.

Active bus-hold circuitry sustains valid logic states on undriven A/B inputs (IBHL up to 100μA, IBHH down to –100μA), eliminating external pull resistors. The Ioff feature limits leakage to ±2μA when either VCCA or VCCB is at 0V, supporting safe partial-power-down operation in modular systems.

Key Specifications

Pinout & Package

74LVCH8T245DBQRG4 uses a 24-pin SSOP (Shrink Small Outline Package) with 0.635mm pitch and 8.2mm × 7.8mm body size. Pin 1 is VCCA; pins 11, 12, 13 are GND; pins 23–24 are VCCB; DIR (pin 2) and OE (pin 22) are referenced to VCCA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC8T245RHLR, 74LVCH8T245DBQRG4 offers proven SSOP manufacturability and wider VCCA/VCCB overlap (1.65–5.5V vs. 1.2–3.6V/1.65–5.5V), while TXB0108PWR trades manual direction control for automatic sensing - making 74LVCH8T245DBQRG4 optimal for deterministic, protocol-aware level translation.

Availability

74LVCH8T245DBQRG4 is available at Aetrix Electronics and suitable for industrial data acquisition, smart energy metering, medical diagnostic equipment, and wired industrial networking requiring stable component supply across extended product lifecycles.

Supply support for 74LVCH8T245DBQRG4 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 communications markets.

The SN74LVCH8T245 belongs to TI's LVCH logic family, engineered for low-voltage bidirectional translation with integrated bus-hold and robust power sequencing - targeting industrial and infrastructure systems demanding reliability across mixed-voltage interfaces.

FAQ

What voltage ranges does the 74LVCH8T245DBQRG4 support on its VCCA and VCCB rails?

The 74LVCH8T245DBQRG4 supports 1.65V to 5.5V independently on both VCCA and VCCB rails. This allows translation between common logic families including 1.8V, 2.5V, 3.3V, and 5V domains - for example, 1.8V microcontroller to 5V peripheral communication. Operation outside this range risks damage or undefined behavior.

Does the 74LVCH8T245DBQRG4 require external pull-up or pull-down resistors on its I/O pins?

No. The 74LVCH8T245DBQRG4 integrates active bus-hold circuitry on all A1–A8 and B1–B8 pins, sustaining valid logic states without external resistors. Using pull-up or pull-down resistors disables the bus-hold function and is explicitly discouraged in the datasheet.

How does the 74LVCH8T245DBQRG4 behave when one supply rail is powered off?

When either VCCA or VCCB drops below 100mV or floats, the 74LVCH8T245DBQRG4 automatically places all A- and B-port outputs into high-impedance state - preventing bus contention. This VCC isolation feature is intrinsic and requires no external circuitry.

What is the maximum output drive capability of the 74LVCH8T245DBQRG4?

The 74LVCH8T245DBQRG4 delivers ±32mA output current per pin when VCCO is 4.5–5.5V. At lower voltages, drive scales down: ±24mA at 3.0–3.6V, ±8mA at 2.3–2.7V, and ±4mA at 1.65V. This enables direct driving of moderate capacitive loads or paralleling outputs for increased strength.

Is the 74LVCH8T245DBQRG4 compatible with partial-power-down systems?

Yes. The 74LVCH8T245DBQRG4 includes Ioff circuitry that limits input/output leakage to ±2μA when either VCCA or VCCB is at 0V. This protects powered sections from back-current and enables safe subsystem-level power gating - essential for energy-efficient industrial and medical designs.