Texas Instruments SN74F74D

Overview

SN74F74D from Texas Instruments is a dual positive-edge-triggered D-type flip-flop with independent preset and clear inputs, operating at 5 V supply voltage, supporting up to 80 MHz clock frequency, with propagation delays as low as 3 ns (t_PLH), and rated for 0°C to 70°C industrial temperature range. It serves as a synchronous storage element in digital logic control, state machine sequencing, and data synchronization circuits.

For engineers reviewing the SN74F74D datasheet, SN74F74D pinout, SN74F74D application, or SN74F74D equivalent, key selection considerations include its TTL-compatible input thresholds (V_IL = 0.8 V, V_IH = 2 V), guaranteed output drive (I_OL = 20 mA), asynchronous preset/clear behavior, and SOIC-14 package compatibility with legacy 74F logic layouts.

Technical Context

This device implements two independent edge-triggered D latches with active-low asynchronous controls: PRE and CLR override clock and data on any positive clock edge. Each flip-flop features non-overlapping setup (t_su = 2–3 ns) and hold (t_th = 1–2 ns) timing relative to CLK↑, and supports direct output-to-output cascading via Q/Q̅ complementary outputs.

It uses bipolar TTL circuitry with Schottky-clamped transistors, delivering fast switching (f_max = 80 MHz at V_CC = 5 V, T_A = 25°C), defined DC output levels (V_OH ≥ 2.5 V, V_OL ≤ 0.5 V), and robust noise immunity (V_IK = –1.2 V clamp voltage).

Key Specifications

Pinout & Package

SN74F74D is housed in a 14-pin Small Outline Integrated Circuit (SOIC) package, 3.91 mm wide, 8.65 mm long, and 1.75 mm maximum height, with gull-wing leads and RoHS-compliant NiPdAu plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS74ADR and SN74AC74DR, the SN74F74D delivers optimal balance of speed, TTL compatibility, and proven reliability in legacy 5 V digital systems - making it the preferred choice for repair, upgrade, and education contexts where interface fidelity and timing predictability are essential.

Availability

SN74F74D is available at Aetrix Electronics and suitable for industrial control logic, digital test equipment, legacy system repair, and electronics education requiring stable component supply across long-lifecycle programs.

Supply support for SN74F74D 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and consumer applications.

The SN74F74D belongs to TI's 74F Fast TTL logic family, designed specifically to deliver higher-speed alternatives to 74LS while maintaining full pin and voltage compatibility with existing TTL-based digital systems.

FAQ

What is the maximum clock frequency supported by the SN74F74D?

The SN74F74D supports a maximum clock frequency of 80 MHz under recommended operating conditions (V_CC = 4.5–5.5 V, T_A = 0°C to 70°C). This value is validated across process, voltage, and temperature corners per the SDFS046A datasheet. At 25°C and 5 V, typical operation reaches 100 MHz, but 80 MHz is the guaranteed minimum across the full industrial temperature range. The SN74F74D achieves this via Schottky-clamped bipolar transistor design, distinguishing it from slower 74LS variants.

Does the SN74F74D have complementary outputs?

Yes, the SN74F74D provides true and inverted outputs (Q and Q̅) for each of its two flip-flops - pins 5/6 and 13/14 respectively. These complementary outputs are internally generated and electrically balanced, enabling direct implementation of toggle modes, JK-equivalent behavior, and differential signaling without external inverters. This feature is explicitly confirmed in the function table and logic diagram of the SN74F74D datasheet (SDFS046A, page 2–2).

Can the SN74F74D operate at 3.3 V supply voltage?

No, the SN74F74D is not rated for 3.3 V operation. Its absolute maximum supply voltage is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. At 3.3 V, input thresholds (V_IL = 0.8 V, V_IH = 2.0 V) become unreliable, propagation delays increase unpredictably, and output drive capability degrades significantly. For 3.3 V systems, consider CMOS alternatives like SN74AC74DR - but note that SN74F74D requires a 5 V rail and level-shifting if interfacing with 3.3 V logic.

Is the SN74F74D pin-compatible with the SN74LS74A?

Yes, the SN74F74D is pin-compatible with the SN74LS74A in the SOIC-14 (D) package - both share identical pin assignments for 1CLR, 1D, 1CLK, 1PRE, 1Q, 1Q̅, GND, V_CC, 2CLR, 2D, 2CLK, 2PRE, 2Q, and 2Q̅. However, SN74F74D offers faster timing (80 MHz vs. 30 MHz), higher output drive (20 mA vs. 8 mA), and improved noise immunity. No PCB changes are required for replacement, though timing-critical designs should verify setup/hold margins due to reduced t_su/t_th.

What does the "D" suffix indicate in SN74F74D?

The "D" suffix in SN74F74D denotes the SOIC (Small Outline Integrated Circuit) package - a 14-pin surface-mount outline with 1.27 mm lead pitch, 3.91 mm body width, and 1.75 mm maximum height. This is distinct from "N" (PDIP), "J" (CDIP), or "FK" (LCCC) variants. The SN74F74D is obsolete per TI's packaging addendum, but actively supported through Aetrix Electronics' extended-life program with traceable, RoHS-compliant stock.