Texas Instruments CD74AC174E

Overview

CD74AC174E from Texas Instruments is a 16-pin PDIP-packaged positive-edge-triggered hex D-type flip-flop with asynchronous clear (CLR), operating across 1.5 V to 5.5 V supply, delivering ±24 mA output drive, balanced propagation delays, and SCR-latchup-resistant CMOS process - used in digital register storage and synchronous data latching within industrial control logic.

For engineers reviewing the CD74AC174E datasheet, CD74AC174E pinout, CD74AC174E application, or CD74AC174E equivalent, this page delivers verified package mapping (PDIP-16), functional timing specs at 1.5 V/3.3 V/5 V, absolute max ratings, real-world noise immunity (30% of VCC), and confirmed alternative options for register-level logic replacement.

Technical Context

The CD74AC174E implements six independent D-type latches triggered on the rising edge of CLK, each with buffered inputs and single-rail outputs. Its direct asynchronous CLR input forces all Q outputs low regardless of clock state, enabling immediate register reset without cycle dependency.

Designed for wide-supply operation (1.5 V–5.5 V), it maintains balanced tPLH/tPHL propagation delays (e.g., 3.4–13.5 ns at 5 V, CL = 50 pF) and supports fanout to 15 F-series devices. The SCR-latchup-resistant CMOS process ensures robustness against transient-induced failure in noisy environments.

Key Specifications

Pinout & Package

CD74AC174E uses a 16-pin plastic dual in-line package (PDIP, N package), body size 19.3 mm × 6.35 mm, with through-hole mounting and industry-standard pin spacing (2.54 mm). Thermal resistance RθJA is 67 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AC174N and 74AC174PC, CD74AC174E offers guaranteed TI-manufactured consistency, full -55°C to +125°C qualification, and documented SCR-latchup immunity - making it preferred for industrial and automotive deployments requiring long-term reliability assurance.

Availability

CD74AC174E is available at Aetrix Electronics and suitable for industrial PLC register storage, test equipment data capture, motor control logic sequencing, and legacy system bus interface applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74AC174E 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 specializing in analog, embedded processing, and logic ICs, with over 50 years of leadership in high-reliability logic families.

CD74AC174E belongs to TI's CD74AC advanced CMOS logic series, designed specifically for wide-supply, high-noise-immunity digital register and storage applications in industrial, automotive, and instrumentation systems.

FAQ

What is the maximum clock frequency supported by CD74AC174E at 5 V supply?

At VCC = 5 V ± 0.5 V and TA = –55°C to +125°C, CD74AC174E supports a maximum clock frequency of 108 MHz. This value is specified in Section 5.8 of the TI datasheet and assumes proper load conditions (CL = 50 pF) and valid input timing margins. The CD74AC174E achieves this speed while maintaining balanced tPLH/tPHL delays and ±24 mA drive strength - making it suitable for high-throughput register applications.

Does CD74AC174E support operation at 1.8 V supply voltage?

Yes, CD74AC174E supports operation at 1.8 V, as its specified supply range is 1.5 V to 5.5 V. At 1.8 V, timing parameters such as tPLH/tPHL increase (e.g., ~154 ns max at VCC = 1.5 V), and output drive reduces proportionally, but functionality remains fully guaranteed per TI's recommended operating conditions in Section 5.3. The CD74AC174E is commonly used in mixed-voltage systems where 1.8 V logic interfaces with higher-voltage peripherals.

What is the purpose of the CLR pin on CD74AC174E, and how does it behave?

The CLR (Pin 1) on CD74AC174E is an active-low asynchronous clear input that forces all six Q outputs low immediately, regardless of clock state or input data. It operates independently of the CLK signal and takes effect within tPLH/tPHL delay (e.g., 181 ns max at 1.5 V). This behavior makes CD74AC174E ideal for system-level reset functions where deterministic register clearing is required prior to initialization or fault recovery sequences.

Can CD74AC174E replace CD74HC174 in an existing design?

CD74AC174E can replace CD74HC174 in many cases due to shared pinout and function, but key differences exist: CD74AC174E offers faster speed (108 MHz vs. ~25 MHz for HC), higher drive (±24 mA vs. ±4 mA), and wider VCC range (1.5–5.5 V vs. 2–6 V). However, AC logic has lower noise margin at high VCC and different input thresholds. Verify timing closure and noise immunity in the target application before substitution - CD74AC174E is not a drop-in replacement without validation.

What package type is used for CD74AC174E, and what are its mechanical dimensions?

CD74AC174E uses the N package - a 16-pin plastic dual in-line package (PDIP) with body size 19.3 mm × 6.35 mm and overall length 19.3 mm × 9.4 mm including leads. Lead pitch is 2.54 mm, and it is supplied in tubes of 25 units. This through-hole package supports manual prototyping and legacy wave-solder assembly, and its RθJA of 67 °C/W enables reliable thermal performance in natural-convection environments.