Texas Instruments SN74LVCH8T245PWR

Overview

SN74LVCH8T245 from Texas Instruments is an 8-bit dual-supply noninverting bus transceiver enabling bidirectional voltage-level translation between 1.65V–5.5V domains. It features independent VCCA and VCCB rails, bus-hold on all data inputs, Ioff partial-power-down protection, and VCC isolation-used in smart meter backplanes and industrial wired networking interfaces requiring robust level shifting.

For engineers reviewing the SN74LVCH8T245 datasheet, SN74LVCH8T245 pinout, SN74LVCH8T245 application, or SN74LVCH8T245 equivalent, key selection criteria include dual-rail operating range (1.65V–5.5V per rail), 3-state control referenced to VCCA, bus-hold elimination of external resistors, and guaranteed glitch-free power sequencing across mixed-voltage subsystems.

Technical Context

The SN74LVCH8T245 implements a fully configurable dual-rail architecture where A-port I/Os and control inputs (DIR, OE) are referenced to VCCA, while B-port I/Os track VCCB-enabling asynchronous bidirectional translation without direction latching. Its active bus-hold circuitry sustains valid logic states on undriven A/B inputs, eliminating pullup/pulldown requirements.

Power integrity is ensured via VCC isolation: if either VCCA or VCCB falls below 100 mV or floats, all outputs enter high-impedance state. Ioff circuitry limits leakage to ±2 µA during partial-power-down, meeting JESD78 Class II latch-up (>100 mA) and JESD22 ESD ratings (±4 kV HBM, ±1 kV CDM).

Key Specifications

Pinout & Package

Packaged in TSSOP-24 (PW), this device measures 7.8 mm × 6.4 mm with 0.65 mm pitch. Pin 1 = VCCA, Pins 11/12/13 = GND, Pins 23/24 = VCCB, Pin 2 = DIR, Pin 22 = OE, Pins 3–10 = A1–A8, Pins 14–21 = B8–B1 (reversed order per top-view diagram).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC8T245 and TXS0108E, the SN74LVCH8T245 uniquely supports full 1.65V–5.5V translation with integrated bus-hold and VCC isolation-making it the only option for industrial 5V↔3.3V backplane bridging where reliability under uncontrolled power sequencing is mandatory.

Availability

SN74LVCH8T245 is available at Aetrix Electronics and suitable for smart meter backplanes, industrial wired networking nodes, medical imaging data acquisition, and grid infrastructure RTU communication requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for SN74LVCH8T245 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 for industrial, automotive, and personal electronics markets.

The SN74LVCH8T245 belongs to TI's LVCH logic family, engineered for robust mixed-voltage system interfacing-specifically targeting applications where power-rail independence, bus-hold, and Ioff protection are essential for field reliability.

FAQ

What voltage ranges does the SN74LVCH8T245 support on its A and B ports?

The SN74LVCH8T245 supports 1.65V to 5.5V on both VCCA and VCCB rails independently. This allows bidirectional translation between any combination of standard logic voltages-including 1.8V↔3.3V, 2.5V↔5V, and 1.8V↔5V-without external biasing or level-shifting components. The device tolerates input voltages up to 6.5V on all I/O pins regardless of rail settings.

How does the SN74LVCH8T245 handle power sequencing when VCCA and VCCB are powered independently?

The SN74LVCH8T245 features glitch-free power sequencing: either VCCA or VCCB may be powered on or off in any order without causing output glitches. If one supply drops below 100 mV or floats, VCC isolation forces all outputs into high-impedance state-preventing bus contention. This behavior is intrinsic to the silicon design and requires no external circuitry.

Does the SN74LVCH8T245 require external pullup or pulldown resistors on its data lines?

No. The SN74LVCH8T245 integrates active bus-hold circuitry on all 16 data I/Os (A1–A8, B1–B8), which maintains valid logic states on undriven or floating inputs. Using external resistors disables the bus-hold feature and is explicitly discouraged in the datasheet. This eliminates ≥16 passive components per device in typical implementations.

What is the maximum output drive strength of the SN74LVCH8T245, and how is it specified?

The SN74LVCH8T245 delivers ±32 mA output drive at VCCO = 4.5V–5.5V, with lower drive at reduced voltages (e.g., ±24 mA at 3V, ±8 mA at 2.5V). This high-drive capability enables fast edge rates into light loads. Two outputs may be paralleled for up to ±64 mA drive-provided thermal limits (RθJA = 100.6°C/W for TSSOP) and absolute maximum ratings (±50 mA continuous per pin) are observed.

Can the SN74LVCH8T245 be used in partial-power-down applications, and what protection does it provide?

Yes. The SN74LVCH8T245 includes Ioff circuitry that limits input/output leakage to ±2 µA when either VCCA or VCCB is at 0V-preventing damaging backflow current into powered subsystems. This meets JESD78 Class II latch-up immunity (>100 mA) and enables safe use in modular systems where subsections power down independently, such as in smart meter sleep modes or network node standby states.