Texas Instruments SN74LVCH8T245DBQR

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 (e.g., 1.8V ↔ 3.3V, 3.3V ↔ 5V). It features configurable VCCA/VCCB rails, bus-hold on all data I/Os, Ioff partial-power-down protection, and VCC isolation-used in industrial communications interfaces where mixed-voltage subsystems require glitch-free data exchange.

For engineers reviewing the SN74LVCH8T245 datasheet, SN74LVCH8T245 pinout, SN74LVCH8T245 application, or SN74LVCH8T245 equivalent, key selection criteria include dual-rail level-shifting capability, 3-state output control via DIR/OE referenced to VCCA, bus-hold elimination of external resistors, and robust power sequencing across wide voltage ranges.

Technical Context

The SN74LVCH8T245 implements a fully asynchronous, dual-rail CMOS 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. OE independently places both ports into high-impedance state.

Its active bus-hold circuitry sustains valid logic states on undriven A/B inputs without external components, and Ioff limits leakage to ±2 μA when either VCCA or VCCB is at 0 V-enabling safe partial-power-down operation. VCC isolation forces all outputs to high-Z if either supply drops below 100 mV or floats.

Key Specifications

Pinout & Package

SN74LVCH8T245DBQR uses a 24-pin SSOP (DB) package measuring 8.2 mm × 7.8 mm with gull-wing leads. Pin assignment is identical across DB, DGV, PW, and RHL packages per TI's mechanical documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH8T245 and TXB0108, the SN74LVCH8T245 uniquely balances wide voltage compatibility (1.65V–5.5V), explicit DIR control for deterministic bus arbitration, and integrated bus-hold-making it the only option among the three qualified for industrial mixed-voltage backplanes with floating-bus reliability requirements.

Availability

SN74LVCH8T245 is available at Aetrix Electronics and suitable for video surveillance systems, smart metering platforms, and grid infrastructure equipment requiring stable component supply across extended temperature and mixed-voltage operating 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 leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74LVCH8T245 belongs to TI's LVCH logic family-designed specifically for robust, low-power, mixed-voltage system interfacing in harsh industrial environments where power sequencing, ESD resilience, and long-term supply stability are critical.

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 (A port) and VCCB (B port), enabling translation between any combination of common logic voltages-including 1.8V, 2.5V, 3.3V, and 5V domains. This range is validated across –40°C to +85°C and applies to both input tolerance and output drive capability. The SN74LVCH8T245 does not support sub-1.65V operation or 6V+ supplies.

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 erroneous output transitions. Its internal design ensures outputs remain stable or enter high-Z during rail transitions. If either supply drops below 100 mV or floats, the SN74LVCH8T245 automatically places all I/Os in high-impedance state-preventing bus contention during brownout or hot-swap events.

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 sustains valid logic states on undriven or floating inputs without external components. Using pullup or pulldown resistors with the SN74LVCH8T245 disables the bus-hold function and is explicitly discouraged in TI's datasheet. The SN74LVCH8T245's bus-hold current ranges from ±15 μA (1.65V) to ±100 μA (4.5V).

What is the maximum output drive strength of the SN74LVCH8T245, and under what conditions is it achieved?

The SN74LVCH8T245 delivers up to ±32 mA per output when VCCO = 4.5V–5.5V, as specified in its recommended operating conditions. This drive strength is measured at VOL ≤ 0.55 V and VOH ≥ 3.8 V. At lower VCCO (e.g., 1.65V), output current is reduced to ±4 mA. The SN74LVCH8T245's balanced push-pull outputs allow paralleling two outputs for 2× drive strength-provided thermal limits (RθJA = 88.5°C/W for DB package) are observed.

Can the SN74LVCH8T245 be used in partial-power-down applications where one supply rail is inactive?

Yes. The SN74LVCH8T245 includes Ioff circuitry that limits input/output leakage to ±2 μA when either VCCA or VCCB is at 0 V-enabling safe partial-power-down operation. When VCCA = 0 V, A-port leakage is constrained; when VCCB = 0 V, B-port leakage is constrained. This feature protects powered subsystems from backflow current and is validated per JESD78 Class II latch-up standards. The SN74LVCH8T245 remains compliant across its full industrial temperature range during such conditions.