Texas Instruments SN74LVT240ADWR

Overview

SN74LVT240ADWR from Texas Instruments is an octal buffer/line driver IC designed for 3.3-V V_CC operation with mixed-mode 5-V input/output compatibility. It features two independent 4-bit channels, dual output-enable (OE) inputs, 3.3-V supply operation down to 2.7 V, <0.8 V typical output ground bounce, and I_off/power-up 3-state support for hot insertion in backplane or modular systems.

For engineers reviewing the SN74LVT240ADWR datasheet, SN74LVT240ADWR pinout, SN74LVT240ADWR application, or SN74LVT240ADWR equivalent, this device is selected for level-shifting bus interfaces between 3.3-V logic domains and legacy 5-V TTL subsystems-particularly where hot-swap capability, low ground bounce, and guaranteed high-impedance during power sequencing are required.

Technical Context

The SN74LVT240ADWR implements noninverting buffer functionality with separate OE control per 4-bit group, enabling independent enable/disable of Y1–Y4 and Y1′–Y4′ outputs. Its I_off circuitry actively disables outputs when V_CC = 0 V, preventing current backflow during hot insertion; power-up 3-state ensures outputs remain high-impedance until V_CC exceeds 1.5 V.

It supports TTL-level inputs (V_IL ≤ 0.8 V, V_IH ≥ 2 V) while operating from a 2.7–3.6-V supply, delivering VOH ≥ 2.4 V at I_OH = −8 mA and VOL ≤ 0.5 V at I_OL = 64 mA. Propagation delay is 1.1–4.6 ns (t_PLH/t_PHL) under CL = 50 pF, with enable/disable times as fast as 1.1 ns (t_PZL).

Key Specifications

Pinout & Package

SN74LVT240ADWR is housed in a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm body, 1.27 mm pitch, 2.65 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 applications.

Compared with SN74LVT240ADWR, SN74LVC240APWR trades hot-swap safety for lower cost and smaller footprint, while 74ALVC240MTCX sacrifices 5-V input tolerance for marginal speed gain - making SN74LVT240ADWR the sole choice for mixed-voltage, hot-pluggable bus bridging.

Availability

SN74LVT240ADWR is available at Aetrix Electronics and suitable for backplane buffering, hot-swappable module interfaces, legacy system upgrades, and low-voltage bus isolation requiring stable component supply and long-term industrial availability.

Supply support for SN74LVT240ADWR 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 high-reliability logic and interface solutions.

The SN74LVT240ADWR belongs to TI's LVT (Low-Voltage BiCMOS Technology) family, engineered specifically for mixed-voltage system interfacing and hot-insertion applications in telecom, industrial control, and test equipment.

FAQ

What is the minimum V_CC required for functional operation of the SN74LVT240ADWR?

The SN74LVT240ADWR is fully specified for operation from 2.7 V to 3.6 V. Below 2.7 V, parameters such as VOL, VOH, and t_PD are not guaranteed. At V_CC < 1.5 V, outputs enter high-impedance state regardless of OE status - a feature used for power-down safety, not active operation. The SN74LVT240ADWR must be operated within its recommended 2.7–3.6-V range for reliable data transfer and timing compliance.

Does the SN74LVT240ADWR support true 5-V output swing?

No, the SN74LVT240ADWR does not generate 5-V outputs. Its VOH is specified as ≥2.4 V at I_OH = −8 mA when V_CC = 2.7 V, and ≥2.0 V at I_OH = −32 mA when V_CC = 3.0 V. It accepts 5-V inputs and drives 5-V TTL loads because those devices recognize ≥2.0 V as a valid high level - but the SN74LVT240ADWR itself operates solely from 3.3-V rail and cannot source 5 V.

Can both OE pins of the SN74LVT240ADWR be tied together?

Yes, the 1OE and 2OE pins of the SN74LVT240ADWR can be connected to a common control signal, effectively using the device as a single 8-bit buffer. This configuration is electrically valid and commonly implemented. However, doing so forfeits independent control of the two 4-bit groups - a capability that enables partial bus gating or staggered enable sequencing, which may be needed in advanced timing-critical or power-managed designs involving the SN74LVT240ADWR.

Is a pullup resistor required on OE for proper power-up behavior of the SN74LVT240ADWR?

Yes - to ensure outputs remain high-impedance above V_CC = 1.5 V during power-up, OE should be tied to V_CC via a pullup resistor. The datasheet specifies the minimum value depends on the current-sinking capability of the driving source; for standard CMOS drivers, 10 kΩ is typically sufficient. Without this pullup, OE could float or settle low during ramp-up, causing unintended output activation and potential bus contention - a key design consideration for robust deployment of the SN74LVT240ADWR.

What thermal derating applies to the SN74LVT240ADWR in SOIC (DW) package?

The SOIC (DW) package of the SN74LVT240ADWR has a θ_JA of 58°C/W under standard JEDEC test conditions. At maximum rated I_OL = 64 mA per output (all eight outputs sinking simultaneously), total power dissipation may reach ~180 mW. With ambient temperature at 85°C, junction temperature would rise to ~95°C - within the 150°C absolute max but approaching thermal limits. For sustained high-load operation, PCB copper area, airflow, or reduced output loading should be considered to maintain reliability of the SN74LVT240ADWR.