Texas Instruments SN74LV240APW

Overview

SN74LV240APW from Texas Instruments is an octal inverting buffer/driver with 3-state outputs, designed for 2V to 5.5V V_CC operation. It delivers 6.5ns max propagation delay at 5V, supports mixed-mode voltage translation (inputs tolerant to 5.5V), and features I_off for live insertion and partial power-down. It serves as a bus-oriented transceiver in memory address and clock distribution systems.

For engineers reviewing the SN74LV240APW datasheet, SN74LV240APW pinout, SN74LV240APW application, or SN74LV240APW equivalent, key selection criteria include its 20-pin TSSOP package, dual 4-bit inverted 3-state architecture, 8mA output drive at 3.3V, ground-bounce/undershoot performance, and I_off-enabled system-level hot-swap capability.

Technical Context

The SN74LV240APW implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) control. Its CMOS design enables bidirectional voltage translation: inputs accept up to 5.5V regardless of V_CC (2–5.5V), while outputs swing rail-to-rail within V_CC. The device operates across –40°C to +125°C and meets JESD17 latch-up >250mA.

Functional mode is strictly defined by OE state: when OE is low, inverted A→Y data flow occurs; when OE is high, all eight outputs enter high-impedance. No internal latching or storage is present - it is purely combinational with 3-state control.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.50mm × 6.40mm body, 0.65mm pitch, thin profile suitable for space-constrained PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.

Compared with SN74LVC240APW and 74ALVC240PW, the SN74LV240APW uniquely balances 5.5V input tolerance, industrial-grade latch-up immunity, and broad V_CC support - making it optimal for mixed-voltage, hot-swap-capable infrastructure applications where reliability trumps marginal speed gains.

Availability

SN74LV240APW is available at Aetrix Electronics and suitable for industrial bus transceivers, memory address buffering, smartphone baseband interfaces, and network switch control planes requiring stable component supply across extended temperature ranges.

Supply support for SN74LV240APW 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 with decades of industrial and automotive qualification expertise.

The SN74LV240APW belongs to TI's LV-A family of low-voltage, high-noise-immunity logic devices engineered for reliable 3-state bus interfacing in mixed-voltage, thermally demanding applications.

FAQ

What is the maximum propagation delay of the SN74LV240APW at 5V?

The SN74LV240APW has a maximum propagation delay (t_pd) of 6.5ns at V_CC = 5V ±0.5V, C_L = 15pF, and T_A = 25°C. This value is specified in Section 5.8 of the official datasheet and reflects worst-case timing for A→Y signal transfer under standard load conditions. The SN74LV240APW maintains consistent performance across its full operating temperature range (–40°C to +125°C).

Does the SN74LV240APW support 5V-tolerant inputs when powered from 3.3V?

Yes, the SN74LV240APW supports input voltages up to 5.5V regardless of V_CC level - including when V_CC = 3.3V. This is explicitly confirmed in Section 7.3 ("Feature Description") and Table 5.1 ("Absolute Maximum Ratings"), where V_I max is rated at 7V (with functional operation guaranteed to 5.5V). This enables direct interfacing with 5V controllers without external level-shifting circuitry.

What is the purpose of the I_off feature in the SN74LV240APW?

The I_off feature in the SN74LV240APW limits input/output leakage current to ≤5µA when V_CC = 0V, enabling safe live insertion, partial power-down operation, and back-drive protection. As documented in Section 7.3 and Table 5.5, this prevents damaging current flow during hot-swap events or system power sequencing - a critical requirement for modular industrial and telecom equipment using the SN74LV240APW.

Can the SN74LV240APW drive standard TTL loads?

The SN74LV240APW is not designed to directly drive standard TTL loads due to its CMOS output structure and VOL/VOH specifications optimized for CMOS thresholds. At V_CC = 5V, it delivers VOH ≥ V_CC – 0.1V and VOL ≤ 0.1V (Table 5.5), meeting CMOS but not TTL input thresholds (which require VOH ≥ 2.4V and VOL ≤ 0.4V at 5V). For TTL compatibility, the SN74LV240APW should interface through a TTL-input-compatible buffer or use appropriate termination.

What is the thermal resistance (R_θJA) of the SN74LV240APW in its TSSOP-20 package?

The junction-to-ambient thermal resistance (R_θJA) for the SN74LV240APW in the PW (TSSOP-20) package is 128.2°C/W, as specified in Table 5.4 of the datasheet (Revision K, May 2024). This value assumes standard JEDEC test conditions (1sqa inch 2-layer board, 1 oz copper). Designers must account for this R_θJA when calculating maximum allowable power dissipation at elevated ambient temperatures to ensure junction temperature remains below 150°C.