Texas Instruments SN74LV74AD

Overview

SN74LV74AD from Texas Instruments is a dual positive-edge-triggered D-type flip-flop IC designed for 2-V to 5.5-V V_CC operation, featuring 8.5 ns maximum propagation delay at 5 V, I_off support for partial-power-down mode, and mixed-mode voltage operation on all ports. It serves as a synchronous storage element in digital control logic, clock domain interfacing, and state-holding circuits within industrial PLCs and server motherboard timing subsystems.

For engineers reviewing the SN74LV74AD datasheet, SN74LV74AD pinout, SN74LV74AD application, or SN74LV74AD equivalent, key selection considerations include its dual independent flip-flop architecture with asynchronous preset/clear, wide supply range compatibility, low ground bounce (<0.8 V at 3.3 V), and SOIC-14 package footprint - critical for legacy board reuse and mixed-voltage signal conditioning.

Technical Context

This device implements two identical, independent D-type latches triggered on the rising edge of CLK, each with active-low asynchronous PRE and CLR inputs that override clocked data transfer. Its CMOS design ensures rail-to-rail output swing, input overvoltage tolerance up to 5.5 V regardless of V_CC, and latch-up immunity exceeding 250 mA per JESD17.

The I_off circuitry actively disables outputs during power-down to prevent backflow current, while noise characteristics - including typical VOLP < 0.8 V and VOHV > 2.3 V at 3.3 V - are specified for stable operation in electrically noisy environments such as analog input modules and power supply control circuits.

Key Specifications

Pinout & Package

SN74LV74AD is supplied in a 14-pin SOIC (D) package with nominal body size 8.65 mm × 3.91 mm and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC74A and 74HC74, SN74LV74AD uniquely balances wide supply range (2–5.5 V), guaranteed I_off behavior, and industrial temperature support - making it the optimal choice for mixed-rail embedded controllers where reliability under partial power-down is mandatory.

Availability

SN74LV74AD is available at Aetrix Electronics and suitable for programmable logic controllers, server motherboards, and analog input modules requiring stable component supply across extended temperature and mixed-voltage operating conditions.

Supply support for SN74LV74AD 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 for industrial, automotive, and communications markets.

The SN74LV74A family delivers low-voltage, high-noise-immunity D-type flip-flops optimized for reliable operation in mixed-signal control systems where power sequencing, voltage translation, and ESD robustness are critical.

FAQ

What is the absolute maximum supply voltage for SN74LV74AD?

The absolute maximum V_CC rating for SN74LV74AD is 7 V, as specified in Section 6.1 of the datasheet. However, functional operation is guaranteed only within the recommended range of 2 V to 5.5 V. Exceeding 5.5 V may cause permanent damage or unpredictable behavior, even if below the 7 V absolute limit. Always operate SN74LV74AD within 2–5.5 V for reliable performance.

Does SN74LV74AD support true 5 V TTL input compatibility?

SN74LV74AD does not require 5 V TTL-compatible inputs; instead, it accepts input voltages up to 5.5 V regardless of V_CC, enabling direct interfacing with 5 V logic while powered from 3.3 V or 2.5 V supplies. This overvoltage-tolerant input structure differs from classic TTL thresholds and eliminates external level-shifting components. The SN74LV74AD datasheet confirms this capability in Section 6.3 (Recommended Operating Conditions) and Section 9.2.2.

Can SN74LV74AD be used in hot-swap applications?

Yes, SN74LV74AD supports hot-swap operation via its I_off feature, which disables outputs and blocks current backflow when V_CC is at 0 V. This prevents damage to upstream drivers during live insertion/removal. The datasheet specifies I_off ≤ 5 µA at 3.3 V (Section 6.4), confirming safe isolation. For full hot-swap compliance, pair SN74LV74AD with appropriate current-limiting and sequencing circuitry as outlined in TI Application Report SCBA004.

What is the minimum pulse width required for SN74LV74AD's clock input?

At V_CC = 5 V, the minimum clock pulse width (t_w) for SN74LV74AD is 5 ns, as defined in Section 6.10 of the datasheet. This value scales with supply voltage: 6 ns at 3.3 V and 8 ns at 2.5 V. Pulse widths shorter than these limits risk metastability or failure to capture data. These timing requirements apply to both rising and falling edges of the clock signal and must be verified under worst-case temperature and voltage conditions.

Is SN74LV74AD pin-compatible with older 74LS74 or 74HC74 devices?

SN74LV74AD shares the same 14-pin SOIC footprint and pinout as 74LS74 and 74HC74, including identical assignments for PRE, CLR, CLK, D, Q, and Q̅. However, electrical behavior differs significantly: SN74LV74AD features wider V_CC range (2–5.5 V), I_off, and overvoltage-tolerant inputs. While PCB layout is interchangeable, direct substitution requires validation of timing margins, drive strength, and power sequencing - especially in systems relying on LS-series current sinking or HC-series noise margins.