Texas Instruments SN74LVTH240PWR

Overview

SN74LVTH240PWR from Texas Instruments is a 3.3-V ABT octal buffer/driver with 3-state outputs, designed for mixed-mode signal interfacing between 3.3-V logic and 5-V systems. It features dual 4-bit channels, bus-hold on all data inputs, Ioff support for hot insertion, and operates down to 2.7 V supply. Used in backplane interface, memory address buffering, and industrial control bus isolation.

For engineers reviewing the SN74LVTH240PWR datasheet, SN74LVTH240PWR pinout, SN74LVTH240PWR application, or SN74LVTH240PWR equivalent, key selection criteria include 3-state timing (tPZH ≤ 5.6 ns), bus-hold current (±75 µA at VCC = 3 V), output drive strength (IOL = 64 mA), and TSSOP-20 thermal performance (θJA = 83°C/W).

Technical Context

This device implements two independent 4-bit noninverting buffer/driver sections, each with dedicated output-enable (OE) control. Logic operation follows positive-logic enable: low OE enables A→Y data flow; high OE forces outputs into high-impedance state. Bus-hold circuitry actively maintains valid logic levels on unused inputs without external resistors.

Hot-insertion capability is enabled by Ioff protection (±100 µA max at VCC = 0) and power-up 3-state behavior, which holds outputs high-Z during power ramping (Δt/ΔVCC ≤ 200 µs/V). Input tolerance supports 5.5-V signals at 3.3-V VCC, enabling direct connection to legacy 5-V buses.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm, 1.2 mm max height, 0.65 mm lead pitch, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal buffer applications.

Compared with SN74LVC240APWR and SN74AHCT240PW, the SN74LVTH240PWR uniquely combines 5-V-tolerant I/O, bus-hold, Ioff, and 64-mA drive in a single 3.3-V supply - making it the only option for robust mixed-voltage backplane buffering with zero external bias components.

Availability

SN74LVTH240PWR is available at Aetrix Electronics and suitable for industrial control systems, test equipment backplanes, and embedded memory interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVTH240PWR 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 logic solutions for industrial, automotive, and communications markets.

The SN74LVTH240PWR belongs to TI's ABT logic family, engineered for high-speed, mixed-voltage system interfacing with emphasis on hot-swap reliability, bus integrity, and simplified board design.

FAQ

What is the maximum operating temperature range for the SN74LVTH240PWR?

The SN74LVTH240PWR is rated for operation from −40°C to +85°C ambient temperature. This industrial temperature range is validated per the recommended operating conditions table in the official datasheet (SCBS679K), and applies specifically to the TSSOP-20 (PW) package variant. Thermal derating is required above 70°C ambient when operating at full output current.

Does the SN74LVTH240PWR require external pull-up resistors on its OE pins?

Yes - to ensure high-impedance outputs during power-up and power-down, both 1OE and 2OE pins must be tied to VCC through external pull-up resistors. The minimum resistor value depends on the current-sinking capability of the controlling driver; TI recommends verifying against the specific driver's IOH specification to avoid violating the OE input voltage threshold (VIH = 2.0 V min).

Can the SN74LVTH240PWR safely interface with 5-V microcontrollers?

Yes - the SN74LVTH240PWR supports 5-V input signals (up to 5.5 V) while operating from a 3.3-V supply, enabling direct connection to 5-V microcontroller outputs. Its 5-V-tolerant inputs eliminate level-shifting components. However, outputs remain 3.3-V logic levels and are not 5-V tolerant in the high state - they must not be connected to 5-V buses without external clamping or translation.

What is the purpose of the bus-hold circuitry in the SN74LVTH240PWR?

The bus-hold circuitry in the SN74LVTH240PWR actively maintains a valid logic state (high or low) on all eight data inputs when left floating or weakly driven. With ±75 µA hold current at VCC = 3 V, it eliminates the need for external pullup or pulldown resistors - reducing component count, PCB space, and potential noise susceptibility in high-density layouts.

Is the SN74LVTH240PWR pin-compatible with other TSSOP-20 octal buffers like the SN74LVC240A?

No - although both devices use TSSOP-20 packages and share functional similarity, the SN74LVTH240PWR has a different pinout than the SN74LVC240A. Specifically, OE pin locations and Y/A terminal assignments differ; direct replacement would require PCB layout modification. Always verify pin mapping using the respective package drawings (TI PW0020A for SN74LVTH240PWR vs. PW0020B for SN74LVC240A).