Texas Instruments SN74HC74NE4

Overview

SN74HC74NE4 from Texas Instruments is a dual D-type positive-edge-triggered flip-flop with asynchronous clear and preset inputs per channel, operating across 2 V to 6 V supply voltage and –40°C to +85°C temperature range. It delivers 35 pF typical power dissipation capacitance, supports up to 10 LSTTL loads, and enables clock division by 2 or 4 in digital timing circuits.

For engineers reviewing the SN74HC74NE4 datasheet, SN74HC74NE4 pinout, SN74HC74NE4 application, or SN74HC74NE4 equivalent, this device serves as a foundational building block for synchronous logic design, toggle switch conversion, and edge-sensitive state storage-requiring attention to setup/hold timing (e.g., 21 ns tsu at 6 V), propagation delay (as low as 15 ns), and proper input termination.

Technical Context

The SN74HC74NE4 implements two independent CMOS D-flip-flops sharing no internal coupling-each with dedicated asynchronous active-low PRE and CLR inputs, a positive-edge-triggered CLK, and complementary Q/Q outputs. Its balanced push-pull output stage sources/sinks comparable current, enabling reliable interfacing with LSTTL and other CMOS loads.

It operates under standard CMOS input conditions: high-impedance inputs with ≤10 pF capacitance and ±1 µA leakage at 6 V, requiring fast input transitions (≤400 ns rise/fall at 6 V) to prevent shoot-through. The device follows a defined function table where PRE=LOW forces Q=HIGH, CLR=LOW forces Q=LOW, and simultaneous LOW on both creates a nonstable H/H state.

Key Specifications

Pinout & Package

Packaged in 14-pin PDIP (Plastic Dual In-line Package) with 19.30 mm × 6.40 mm body size, SN74HC74NE4 uses through-hole mounting and features standard 0.3-inch row spacing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC74NE4, SN74HCT74N offers seamless TTL integration at no layout change, while MC74HC74ANG extends operational reliability to extreme environments-neither is pin-compatible with surface-mount variants but matches SN74HC74NE4's through-hole footprint and logic behavior.

Availability

SN74HC74NE4 is available at Aetrix Electronics and suitable for industrial control panels, test equipment front-ends, and legacy 5 V digital systems requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for SN74HC74NE4 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 solutions for industrial, automotive, and communications markets.

SN74HC74NE4 belongs to the 74HC logic family-designed for low-power, high-noise-immunity digital control in cost-sensitive, board-space-constrained applications where compatibility with both CMOS and TTL signaling is essential.

FAQ

What is the maximum clock frequency supported by SN74HC74NE4?

The SN74HC74NE4 supports a maximum clock frequency of 29 MHz at VCC = 6 V and TA = –40°C to +85°C, as specified in Section 6.7 of the TI datasheet. At 4.5 V, the guaranteed maximum is 25 MHz, and at 2 V it drops to 5 MHz. These values reflect worst-case timing across temperature and voltage; actual performance may vary slightly in controlled lab conditions, but design margins must adhere to these limits.

Does SN74HC74NE4 require external pull-up or pull-down resistors on unused inputs?

Yes, SN74HC74NE4 requires all unused inputs-including 1D, 1PRE, 1CLR, 2D, 2PRE, and 2CLR-to be terminated to either VCC or GND. Floating CMOS inputs can cause undefined logic states, increased power consumption, and potential device malfunction. A 10-kΩ resistor is commonly used; tie PRE/CLR to VCC (inactive high) unless active-low initialization is needed.

Can SN74HC74NE4 drive LED indicators directly?

No, SN74HC74NE4 should not drive LEDs directly. Its output current capability is limited to ±25 mA continuous (Section 6.1), but typical VOL/VOH specs assume much lower loads (e.g., 4 mA). Driving an LED risks exceeding VOL spec, causing logic-level corruption or thermal stress. Use a discrete transistor or dedicated LED driver stage instead.

What is the purpose of the inverted output (Q) on SN74HC74NE4?

The inverted output (Q) on SN74HC74NE4 provides the logical complement of Q without requiring an external inverter. This enables compact T-flip-flop configuration (D = Q), simplifies J-K emulation, and supports differential signaling in noise-sensitive layouts. It shares the same timing characteristics and drive strength as Q, ensuring matched propagation delays.

Is SN74HC74NE4 RoHS compliant and lead-free?

Yes, SN74HC74NE4 is RoHS compliant and lead-free. Per TI's official packaging information, the "E4" suffix denotes a lead-free, RoHS-compliant PDIP package with matte tin lead finish. It meets JEDEC J-STD-609 Category 1 requirements and is suitable for environmentally regulated production environments.