Diodes Incorporated 74LVC540AQ20-13

Overview

74LVC540AQ20-13 from Diodes Incorporated is an octal inverting 3-state buffer/line driver in a 20-pin V-QFN4525 package, operating from 1.65V to 3.6V supply, sinking/sourcing up to 24mA at VCC = 3.0V, with 5.5V-tolerant inputs and IOFF partial power-down protection-designed for bus driving and memory address buffering in compact embedded systems.

For engineers reviewing the 74LVC540AQ20-13 datasheet, 74LVC540AQ20-13 pinout, 74LVC540AQ20-13 application, or 74LVC540AQ20-13 equivalent, key selection criteria include dual active-low output enables (OE1/OE2), Schmitt-trigger inputs for noise immunity, low propagation delay (≤6.5ns @3.3V), and thermal resistance (θJA = 67°C/W) critical for high-density PCB layouts.

Technical Context

This device implements an octal inverting buffer architecture with two independent active-low 3-state enable inputs (OE1, OE2), where either high input forces all eight outputs into high-impedance state. Its IOFF circuitry actively disables outputs during power-down to prevent backflow current, meeting JESD78 Class I latch-up robustness (>250mA).

Inputs accept voltages up to 5.5V regardless of VCC level, enabling interoperability between 3.3V logic and legacy 5V signal domains. All inputs feature Schmitt-trigger action with hysteresis ≥0.3V, ensuring reliable switching in noisy environments without external filtering.

Key Specifications

Pinout & Package

V-QFN4525-20 package: 4.5mm × 2.5mm × 0.95mm body, 0.50mm lead pitch, exposed thermal pad (pin 20), JEDEC-compliant footprint per AP02001.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC540APWRE4, the 74LVC540AQ20-13 saves 70% board area and improves thermal performance; versus 74LVC541AQ20-13, it provides inherent signal inversion useful for complementing memory address decoding without added gates.

Availability

74LVC540AQ20-13 is available at Aetrix Electronics and suitable for PC motherboard design, industrial PLC I/O expansion, and automotive infotainment subsystems requiring stable component supply and long-term lifecycle support.

Supply support for 74LVC540AQ20-13 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 components for industrial, computing, and consumer markets with ISO/TS 16949 and ISO 14001 certification.

The 74LVC logic family targets low-voltage, high-speed digital interfacing with mixed-voltage compatibility and robust ESD/latch-up performance - designed specifically for space-constrained, thermally demanding embedded systems.

FAQ

What is the function of pins OE1 and OE2?

OE1 and OE2 are independent active-low 3-state enable inputs. If either is high, all eight outputs (B1–B8) enter high-impedance state. Both must be low for normal inverting buffer operation. This dual-enable structure supports fail-safe bus arbitration and hierarchical control in multi-master systems.

Can 74LVC540AQ20-13 interface directly with 5V logic?

Yes - all inputs tolerate up to 5.5V regardless of VCC level (1.65V–3.6V). No level shifter is needed when driving from 5V microcontrollers or sensors. Outputs swing rail-to-rail (0V to VCC), so interfacing to 5V inputs requires external pull-ups or compatible receivers.

How does IOFF protect during partial power-down?

When VCC = 0V, the IOFF circuit disables output transistors, limiting leakage current to ±10μA (max). This prevents back-driving powered sections of the system - critical for hot-swap modules, battery-backed subsystems, or systems with staggered power sequencing.

Is the exposed thermal pad (pin 20) electrically connected?

No - the exposed pad is internally connected only to GND (pin 10) for thermal conduction. It must be soldered to a PCB thermal pad tied to the main ground plane. Electrical connection to GND is mandatory for both thermal performance and ESD path integrity per Diodes' AP02001 layout guidelines.