Texas Instruments SN74AC74NG4

Overview

SN74AC74NG4 from Texas Instruments is a dual positive-edge-triggered D-type flip-flop IC with independent asynchronous clear (CLR) and preset (PRE) inputs per channel, 2V–6V supply operation, <10ns propagation delay at 5V, and complementary Q/Q̅ outputs per flip-flop - used in clock division, switch debouncing, and synchronous logic control in industrial control panels and digital instrumentation.

For engineers reviewing the SN74AC74NG4 datasheet, SN74AC74NG4 pinout, SN74AC74NG4 application, or SN74AC74NG4 equivalent, this page delivers verified functional identity, confirmed 14-pin PDIP package mapping, validated timing parameters at 3.3V/5V, real-world toggle-switch and clock-division use cases, and two technically documented alternative parts with explicit functional and application differences.

Technical Context

The SN74AC74NG4 implements two independent edge-triggered storage elements, each accepting standard CMOS-level inputs and delivering balanced push-pull outputs capable of ±24mA drive at 5V. Its asynchronous PRE/CLR inputs operate active-low and override clocked data behavior, enabling immediate state initialization without clock dependency.

Each channel features true and complement outputs (Q and Q̅), supports rail-to-rail input voltage tolerance up to 6V regardless of VCC, and maintains stable latched states only while powered within 2V–6V - with no power-on reset or default output state guaranteed.

Key Specifications

Pinout & Package

The SN74AC74NG4 is supplied in a 14-pin plastic dual in-line package (PDIP-N), body size 19.3mm × 6.35mm, with through-hole mounting and industry-standard lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC74N, SN74AC74NG4 delivers 47% faster propagation and 6× higher output drive; versus SN74AHC74N, it trades 3.5ns speed for broader voltage tolerance and proven thermal stability in extended-temperature industrial deployments.

Availability

SN74AC74NG4 is available at Aetrix Electronics and suitable for industrial control panels, digital instrumentation, embedded timing modules, and programmable logic interfaces requiring stable component supply across multi-year production cycles.

Supply support for SN74AC74NG4 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, with over 50 years of innovation in high-reliability digital ICs.

The SN74AC74NG4 belongs to TI's Advanced CMOS (AC) logic family, engineered for high-speed, low-power, mixed-voltage digital control in industrial automation, test equipment, and communications infrastructure.

FAQ

What is the maximum clock frequency supported by SN74AC74NG4 at 5V operation?

The SN74AC74NG4 supports a maximum clock frequency of 125MHz at VCC = 5V ± 0.5V, as specified in the Switching Characteristics table (Section 5.8). This value is derived from measured tPLH/tPHL delays and accounts for setup/hold timing margins under recommended operating conditions - not a theoretical limit but a guaranteed performance specification across the full commercial temperature range.

Does SN74AC74NG4 have a power-on reset function to ensure known initial output states?

No, SN74AC74NG4 does not include an internal power-on reset circuit. At power-up, the output states (Q1, Q̅1, Q2, Q̅2) are indeterminate and may vary between units or power cycles. To guarantee a known initial state, external circuitry - such as an RC-based power-on reset network applied to the PRE and CLR pins - must be used, as demonstrated in the typical application schematic (Figure 8-1).

Can SN74AC74NG4 drive a 50pF capacitive load while maintaining its specified timing parameters?

Yes, SN74AC74NG4 is characterized and guaranteed to meet all timing specifications - including propagation delay, setup/hold times, and maximum clock frequency - when driving a total capacitive load of ≤50pF, as stated in Section 8.2.1.1. Exceeding this load increases rise/fall times and may violate timing margins; for heavier loads, buffer stages or reduced clock rates are required.

Is SN74AC74NG4 compatible with 3.3V-only systems despite its 2V–6V VCC range?

Yes, SN74AC74NG4 operates fully compatibly in 3.3V systems: it meets all recommended operating conditions at VCC = 3.3V ± 0.3V, delivers 100MHz maximum clock frequency, and maintains VIH/VIL thresholds scaled to 3.3V levels (VIH = 2.1V min, VIL = 0.9V max). Its inputs also tolerate up to 6V, allowing safe interfacing with higher-voltage control signals without level shifters.

What is the thermal resistance (RθJA) of SN74AC74NG4 in its PDIP package?

The SN74AC74NG4 in the N (PDIP-14) package has a junction-to-ambient thermal resistance (RθJA) of 80°C/W, as listed in Section 5.3. This value assumes standard JEDEC 2-layer board conditions and enables thermal design calculations for continuous operation - for example, at 20mA average output current and 5V supply, power dissipation remains below 100mW, resulting in <8°C junction rise above ambient.