Texas Instruments SN74LV574AZQNR

Overview

SN74LV574AZQNR from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, designed for 2-V to 5.5-V operation. It features 7.1-ns maximum propagation delay at 5 V, Ioff support for partial-power-down mode, and balanced CMOS 3-state outputs enabling bus interface in LED displays and network switches.

For engineers reviewing the SN74LV574AZQNR datasheet, SN74LV574AZQNR pinout, SN74LV574AZQNR application, or SN74LV574AZQNR equivalent, this page delivers verified functional role, timing behavior under 3.3-V/5-V supply, 3-state enable control logic, and real-world implementation guidance for bus buffering and I/O expansion.

Technical Context

The SN74LV574AZQNR implements eight independent D-type latches triggered on the positive clock edge, with a shared active-low output-enable (OE) controlling all eight outputs simultaneously. Its 3-state outputs drive highly capacitive or low-impedance loads while supporting mixed-mode voltage operation across input and output ports.

It incorporates Ioff circuitry that disables outputs during power-down to prevent backflow current, and features clamping diodes on all inputs/outputs for ESD protection. The device operates across –40°C to +85°C and meets JESD17 latch-up requirements exceeding 250 mA.

Key Specifications

Pinout & Package

SN74LV574AZQNR is packaged in a 20-pin VQFN (RGY) with 4 mm × 3.5 mm body size and wettable flank leads for automated optical inspection. Thermal resistance RθJA is 37°C/W, supporting high-density PCB layouts with minimal heatsinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop applications.

Compared with SN74LV574AZQNR, SN74LVC574A offers better speed in 3.3-V domains but lacks 5-V tolerance, while 74AHC574 provides stronger drive but sacrifices Ioff safety and noise performance-making SN74LV574AZQNR optimal for mixed-voltage, hot-swap-capable, and noise-critical I/O expansion.

Availability

SN74LV574AZQNR is available at Aetrix Electronics and suitable for LED displays, telecom infrastructure, and industrial I/O expanders requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74LV574AZQNR 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 and embedded processing technologies, with over 90 years of innovation in precision logic, power management, and signal chain solutions.

The SN74LV574AZQNR belongs to TI's LV family of low-voltage, high-speed logic devices engineered for robust bus interface, I/O expansion, and mixed-signal system integration in industrial, communications, and computing applications.

FAQ

What is the function of the OE pin on the SN74LV574AZQNR?

The OE (output enable) pin on the SN74LV574AZQNR is an active-low control that places all eight Q outputs simultaneously into high-impedance state when asserted high. When OE is low, outputs reflect the latched D-input values on the next positive CLK edge. This enables bus sharing without contention, and OE does not affect internal latch states-data remains retained during high-impedance operation. For reliable power-up behavior, TI recommends tying OE to VCC via a pullup resistor.

Does the SN74LV574AZQNR support 5-V input signals when powered at 3.3 V?

Yes, the SN74LV574AZQNR supports 5-V-tolerant inputs across its full operating range (2 V to 5.5 V VCC). When powered at 3.3 V, all D inputs, CLK, and OE accept voltages up to 5.5 V without damage or level-shifting circuitry. This mixed-mode capability allows seamless interfacing between legacy 5-V peripherals and modern 3.3-V system controllers, a key advantage confirmed in TI's Electrical Characteristics table and Feature Description section.

What is the maximum clock frequency supported by the SN74LV574AZQNR?

The SN74LV574AZQNR supports a maximum clock frequency of 110 MHz at VCC = 5 V with CL = 15 pF, and 65 MHz at VCC = 3.3 V under the same load. These values derive directly from the fmax specifications in Sections 6.9–6.11 of the datasheet. Real-world achievable frequency depends on trace capacitance, termination, and output loading-TI recommends limiting total capacitive load to ≤50 pF for guaranteed timing compliance across temperature and voltage corners.

How does the Ioff feature of the SN74LV574AZQNR improve system reliability?

The Ioff feature of the SN74LV574AZQNR disables all outputs and limits leakage current to ≤5 µA when VCC = 0 V, preventing damaging backflow current from live buses into unpowered sections of a system. This is critical for hot-swap, partial-power-down, and modular backplane architectures. Unlike standard logic devices, SN74LV574AZQNR maintains safe isolation during power transitions-verified in Section 8.3.3 and Electrical Characteristics Table 6.5-making it suitable for NEBS-compliant telecom and industrial equipment.

What package type is used for the SN74LV574AZQNR, and what are its layout advantages?

The SN74LV574AZQNR uses a 20-pin VQFN (RGY) package measuring 4 mm × 3.5 mm with exposed thermal pad and wettable flank leads. Its low-profile, leadless construction enables high PCB density and superior thermal performance (RθJA = 37°C/W). The wettable flanks support automated optical inspection (AOI) of solder joints, improving manufacturing yield. Layout best practices include placing a 0.1-µF ceramic decoupling capacitor within 2 mm of the VCC pin and routing CLK/D/OE traces away from noisy power planes to minimize jitter and crosstalk.