Texas Instruments CD74HC74EG4

Overview

CD74HC74EG4 from Texas Instruments is a dual D-type positive-edge-triggered flip-flop with independent asynchronous clear and preset inputs per channel, operating from 2 V to 6 V supply, supporting –55°C to +125°C temperature range, and delivering ≤45 ns propagation delay at 6 V with 50 pF load - used in clock division and momentary-to-toggle switch conversion.

For engineers reviewing the CD74HC74EG4 datasheet, CD74HC74EG4 pinout, CD74HC74EG4 application, or CD74HC74EG4 equivalent, key selection criteria include dual-channel edge-triggered storage, rail-to-rail CMOS output drive, wide industrial temperature support, and compatibility with legacy HC logic families.

Technical Context

This device implements two fully independent D-type latches synchronized to the rising edge of their respective clock inputs, each with active-low asynchronous preset and clear that override clock and data. Its balanced CMOS push-pull outputs source/sink up to ±25 mA while maintaining VOH ≥ 5.48 V and VOL ≤ 0.4 V at 6 V/5.2 mA.

Input structure uses standard high-impedance CMOS with 10 pF typical input capacitance and ±1 µA leakage at 6 V; timing requires minimum 14 ns setup (tsu) and 3 ns hold (th) at 6 V, enabling reliable operation up to 23 MHz maximum clock frequency across full temperature range.

Key Specifications

Pinout & Package

CD74HC74EG4 is supplied in a 14-pin plastic dual in-line package (PDIP-N), with body dimensions 19.30 mm × 6.40 mm and through-hole mounting compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC74EG4, SN74HC74N offers identical performance and qualification, while MC74HC74ANG trades extended temperature capability for lower unit cost - making CD74HC74EG4 the optimal choice for harsh-environment designs requiring guaranteed operation down to –55°C.

Availability

CD74HC74EG4 is available at Aetrix Electronics and suitable for industrial control panels, aerospace avionics modules, and automotive engine management systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC74EG4 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 company headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and communications markets.

The CD74HC74EG4 belongs to TI's legacy high-speed CMOS (HC) logic product line, engineered for low-power, wide-voltage, and extended-temperature digital interfacing and sequencing in mission-critical systems.

FAQ

What is the maximum clock frequency supported by CD74HC74EG4?

The CD74HC74EG4 supports a maximum clock frequency of 23 MHz at 6 V across the full –55°C to +125°C operating range, as specified in Section 6.5 of the TI datasheet. At 4.5 V, the limit is 20 MHz, and at 2 V it drops to 4 MHz. These values reflect guaranteed timing margins under worst-case voltage and temperature conditions, not typical lab measurements.

Does CD74HC74EG4 require external pull-up or pull-down resistors on unused inputs?

Yes, CD74HC74EG4 requires all unused inputs to be terminated - either directly to VCC or GND - because its standard CMOS inputs have high impedance and floating nodes can cause oscillation, shoot-through current, or undefined outputs. A 10-kΩ resistor is commonly used if dynamic control is needed; direct connection is preferred for static default states.

Can CD74HC74EG4 drive LSTTL loads directly?

Yes, CD74HC74EG4 supports fanout up to 10 LSTTL loads per output, as stated in its features list. This is enabled by its ±25 mA output drive capability and rail-aligned VOH/VOL specifications - allowing direct interface with legacy 74LS-series logic without level shifters or buffers in most cases.

What is the purpose of the complement outputs (Q̅) on CD74HC74EG4?

The complement outputs (pins 6 and 8) on CD74HC74EG4 provide inverted versions of the true Q outputs, enabling immediate access to both logic states without external inverters. This is essential for applications like J-K flip-flop emulation, differential clock distribution, or feedback paths in counters and shift registers - reducing component count and propagation delay.

Is CD74HC74EG4 compatible with 3.3 V microcontroller GPIOs?

Yes, CD74HC74EG4 operates reliably at 3.3 V supply and accepts 3.3 V logic levels as valid inputs: VIH(min) = 2.31 V and VIL(max) = 1.35 V at VCC = 3.3 V (interpolated from datasheet tables), ensuring robust interfacing with standard 3.3 V MCU I/O without level translation.