Texas Instruments SN74LVTH240NSR

Overview

SN74LVTH240NSR from Texas Instruments is a 3.3-V ABT octal buffer/driver with 3-state outputs, designed for mixed-mode signal operation (5-V inputs/outputs with 3.3-V V_CC), supporting unregulated battery operation down to 2.7 V and featuring bus-hold on all data inputs. It delivers 64 mA low-level output drive at V_CC = 3.3 V and enables hot insertion via I_off and power-up 3-state logic. This device is used in backplane interface and legacy bus bridging applications where level translation and bus contention prevention are critical.

For engineers reviewing the SN74LVTH240NSR datasheet, SN74LVTH240NSR pinout, SN74LVTH240NSR application, or SN74LVTH240NSR equivalent, key selection considerations include its 20-pin SOP-NS package, 3.3-V supply compatibility with 5-V tolerant I/O, bus-hold functionality eliminating external resistors, guaranteed 3-state during power sequencing, and support for industrial temperature range (−40°C to 85°C).

Technical Context

This device integrates two independent 4-bit noninverting buffer/driver sections, each with dedicated output-enable (OE) control. The ABT (Advanced BiCMOS Technology) architecture provides TTL-compatible input thresholds and high-current CMOS outputs while maintaining low static power consumption.

Its bus-hold circuitry actively maintains valid logic states on undriven inputs without external pullup/pulldown resistors, and the I_off protection disables outputs during power-down to prevent backflow current-critical for hot-swap systems. Power-up 3-state ensures outputs remain high-impedance until V_CC stabilizes.

Key Specifications

Pinout & Package

SOP-NS package: 20-pin small-outline plastic package, 0.65 mm lead pitch, 7.5 mm × 5.6 mm body, 2.0 mm max height, 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/driver applications.

Compared with SN74LVC240APWR and SN74AHCT240N, the SN74LVTH240NSR uniquely combines 3.3-V operation, 5-V I/O tolerance, integrated bus-hold, and hot-swap readiness-making it the sole option for robust mixed-voltage backplane interfaces requiring zero external termination and guaranteed 3-state during power transitions.

Availability

SN74LVTH240NSR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy bus bridging, hot-swappable module control, and embedded data acquisition front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVTH240NSR 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 technologies, with decades of experience in industrial-grade logic and interface solutions.

The SN74LVTH240NSR belongs to TI's ABT logic family, engineered specifically for mixed-voltage system interfacing-enabling seamless integration between newer 3.3-V logic and legacy 5-V infrastructure in harsh industrial environments.

FAQ

What is the maximum output current capability of the SN74LVTH240NSR?

The SN74LVTH240NSR supports up to 64 mA per output in the low state (I_OL) at V_CC = 3.3 V, and −32 mA in the high state (I_OH). This drive strength allows direct interfacing with multiple TTL loads or moderate-capacitance buses without external buffers. The SN74LVTH240NSR maintains these ratings across its full operating temperature range (−40°C to 85°C) and supply range (2.7 V to 3.6 V).

Does the SN74LVTH240NSR require external pullup resistors on its inputs?

No, the SN74LVTH240NSR includes active bus-hold circuitry on all eight data inputs, which maintains a valid logic state on undriven or floating inputs without external pullup or pulldown resistors. Using external resistors with the bus-hold feature is explicitly discouraged in the datasheet, as it may cause contention or excessive current draw. The SN74LVTH240NSR's bus-hold current is ±750 μA (dynamic), sufficient to override typical leakage paths.

Can the SN74LVTH240NSR be used in hot-swap applications?

Yes, the SN74LVTH240NSR is explicitly designed for hot-insertion use cases. Its I_off circuitry disables outputs when V_CC = 0 V, preventing damaging current backflow from live backplanes into unpowered modules. Additionally, the power-up 3-state function ensures outputs remain high-impedance during V_CC ramp-up, avoiding bus conflicts. These features are validated per JEDEC standards and documented in the SN74LVTH240NSR datasheet Section 6.

What is the thermal resistance (θ_JA) of the SN74LVTH240NSR in its NS package?

The SN74LVTH240NSR in the SOP-NS package has a junction-to-ambient thermal resistance (θ_JA) of 60°C/W, measured per JESD51-7 on a standard 2-layer JEDEC test board. This value enables reliable operation at full output current (64 mA per channel) without forced airflow, assuming adequate copper pour and thermal vias. The SN74LVTH240NSR's low static ICC (0.19 mA in disabled state) further reduces self-heating under quiescent conditions.

Is the SN74LVTH240NSR compatible with 5-V logic systems?

Yes, the SN74LVTH240NSR supports mixed-mode operation: it operates from a 3.3-V supply (V_CC = 2.7–3.6 V) while accepting 5-V-tolerant inputs (VI up to 7 V) and driving 5-V buses (VO up to 7 V in high-impedance or power-off states). Its output high voltage (VOH) reaches 2.0 V minimum at I_OH = −32 mA, satisfying TTL input thresholds. This makes the SN74LVTH240NSR ideal for bridging 3.3-V controllers to legacy 5-V infrastructure without level-shifter ICs.