Diodes Incorporated 74LVC240AQ20-13

Overview

74LVC240AQ20-13 from Diodes Incorporated is an octal buffer/line driver with 3-state outputs in a 20-pin V-QFN4525 package, operating from 1.65V to 3.6V supply, supporting 5.5V-tolerant inputs and delivering ±24 mA output drive at 3.0V - used for bus driving and signal isolation in mixed-voltage embedded systems.

For engineers reviewing the 74LVC240AQ20-13 datasheet, 74LVC240AQ20-13 pinout, 74LVC240AQ20-13 application, or 74LVC240AQ20-13 equivalent, this device serves as a dual 4-bit non-inverting buffer with independent OE controls, IOFF-enabled partial power-down protection, and Schmitt-trigger inputs for noise immunity in high-density PCB layouts.

Technical Context

The 74LVC240AQ20-13 implements two independent 4-bit non-inverting buffers, each with dedicated output-enable (OE) control pins (Pin 1 and Pin 19), enabling selective tri-state operation of Y outputs while A inputs remain active. Its IOFF circuitry disables outputs during power-down to prevent backflow current.

All eight inputs feature Schmitt-trigger action for hysteresis-based noise rejection, and input voltage tolerance up to 5.5V allows direct interfacing with 5V logic while powered from 1.8V or 3.3V rails - critical for voltage translation in modern low-power computing peripherals.

Key Specifications

Pinout & Package

V-QFN4525-20 package: 2.5 mm × 4.5 mm × 0.95 mm body, 0.50 mm lead pitch, exposed thermal pad (Pin 20 not assigned - thermal pad connected to GND internally).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC240APW and 74LVC240ADTR2G, the 74LVC240AQ20-13 offers superior thermal performance (67 vs. 74/105 °C/W), smallest footprint (2.5×4.5 mm), and guaranteed 24 mA drive down to 3.0V - making it optimal for space- and power-sensitive embedded systems.

Availability

74LVC240AQ20-13 is available at Aetrix Electronics and suitable for PC motherboard bus isolation, industrial PLC I/O expansion, and notebook memory subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74LVC240AQ20-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability, low-power solutions for computing, industrial, and automotive markets.

The 74LVC240A belongs to Diodes' LVC logic family, designed specifically for low-voltage, mixed-signal interface applications demanding 5V-tolerant inputs, IOFF protection, and compact packaging in consumer and industrial electronics.

FAQ

Can 74LVC240AQ20-13 operate reliably at 1.65V supply while driving 24 mA loads?

No - the ±24 mA output drive rating is specified only at VCC = 3.0V. At 1.65V, the maximum guaranteed sink/source current is ±4 mA per output (per Recommended Operating Conditions table). Attempting 24 mA at 1.65V violates absolute maximum ratings and risks excessive VOL/VOLH deviation and thermal overstress.

Is the exposed thermal pad on the QFN-20 package electrically connected, and how should it be handled in layout?

Yes - the exposed thermal pad is internally connected to GND. It must be soldered to a solid copper GND plane on the PCB using at least nine thermal vias (0.3 mm diameter, spaced ≤1 mm apart) to achieve the rated θJA of 67 °C/W. Leaving it floating degrades thermal performance by >30% and risks parametric drift under load.

Does 74LVC240AQ20-13 support hot-plug insertion while other system rails remain active?

Yes - its IOFF circuitry actively disables outputs and limits leakage to ±10 μA when VCC = 0V and inputs are held at 5.5V, satisfying JEDEC JESD78 Class I latch-up immunity and enabling safe hot-plug operation in multi-rail backplane systems without auxiliary power sequencing.

What is the maximum clock frequency supported when using 74LVC240AQ20-13 as a data path buffer?

The device has no internal clock; its usable data rate depends on propagation delay and system timing margins. With tPD = 3.8 ns (typ.) at 3.3V, it supports clean data edges up to ~100 MHz in point-to-point configurations. For 200+ MHz applications, interconnect length, termination, and skew between channels become limiting factors - not the buffer itself.