Texas Instruments SN74HC574NG4

Overview

SN74HC574NG4 from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, designed for bus driving in digital systems. It operates across 2 V to 6 V, delivers ±6 mA output drive at 5 V, exhibits typical propagation delay of 22 ns, and consumes ≤80 µA ICC - enabling robust I/O port and buffer register implementation in industrial control and data acquisition interfaces.

For engineers reviewing the SN74HC574NG4 datasheet, SN74HC574NG4 pinout, SN74HC574NG4 application, or SN74HC574NG4 equivalent, key selection criteria include its 20-pin PDIP package, clock-edge-triggered data capture, independent 3-state output enable (OE), and compatibility with LSTTL bus loads without external pull-ups.

Technical Context

This device implements eight synchronous D-type latches triggered on the low-to-high CLK transition, with a dedicated buffered OE input that places all Q outputs into high-impedance without affecting internal state retention or clock/data operation. Its CMOS architecture ensures low static power and rail-to-rail logic swing across the full 2–6 V supply range.

Each flip-flop supports independent data sampling and storage, while the shared OE terminal enables coordinated bus isolation. The bus-structured pinout minimizes trace crosstalk in parallel data paths, and the design meets standard HC logic thresholds (VIH = 3.15 V @ VCC = 4.5 V, VIL = 1.35 V) for reliable interfacing with microcontrollers and FPGAs.

Key Specifications

Pinout & Package

The SN74HC574NG4 is supplied in a 20-pin plastic dual in-line package (PDIP-N), with nominal body dimensions of 25.40 mm × 6.35 mm and 2.54 mm lead pitch. This through-hole package supports manual prototyping, socket-based testing, and legacy PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT574N and 74LCX574M, the SN74HC574NG4 offers widest supply flexibility (2–6 V), lowest quiescent power (80 µA), and PDIP packaging for prototyping - making it optimal for general-purpose bus interfacing where voltage adaptability and ease of validation are prioritized over extreme speed or ultra-low voltage operation.

Availability

SN74HC574NG4 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, microcontroller parallel port buffering, FPGA configuration data latching, and legacy bus interface bridge applications requiring stable component supply and long-term manufacturability.

Supply support for SN74HC574NG4 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power management, and signal chain technologies.

The SN74HC574NG4 belongs to TI's industry-standard 74HC logic family, engineered for robust bus-driving performance, wide supply tolerance, and seamless integration into industrial, automotive, and communications infrastructure systems.

FAQ

What is the maximum clock frequency supported by the SN74HC574NG4?

The SN74HC574NG4 supports a maximum clock frequency of 24 MHz at VCC = 4.5 V and TA = 25 °C with CL = 50 pF, as specified in the switching characteristics table. At 6 V supply, fmax increases to 28 MHz under identical conditions. Real-world operation depends on load capacitance, trace routing, and temperature - derating is recommended for industrial environments above 70 °C.

Does the SN74HC574NG4 require external pull-up resistors on its 3-state outputs?

No, the SN74HC574NG4 does not require external pull-up resistors on its Q outputs. Its high-current 3-state outputs provide ±6 mA drive capability at 5 V, enabling direct connection to bus lines and compatibility with up to 15 LSTTL loads without interface components. Pull-ups are unnecessary unless specific bus-keeper or fail-safe logic states are required.

Can the SN74HC574NG4 operate reliably at 3.3 V supply voltage?

Yes, the SN74HC574NG4 operates reliably across 2 V to 6 V, including 3.3 V. At VCC = 3.3 V, VIH is guaranteed ≥2.31 V and VIL ≤1.09 V per TI's recommended operating conditions, ensuring compatibility with standard 3.3 V CMOS logic families. Propagation delay increases to ~35 ns, and output drive reduces to ±4 mA - still sufficient for most 3.3 V bus applications.

What is the function of the OE pin on the SN74HC574NG4?

The OE (Output Enable) pin on the SN74HC574NG4 is an active-low control that places all eight Q outputs into high-impedance (tri-state) when asserted (OE = HIGH), and enables normal logic-level outputs (HIGH/LOW) when deasserted (OE = LOW). Critically, OE has no effect on internal flip-flop operation - data can be latched or retained regardless of OE state.

Is the SN74HC574NG4 pin-compatible with other 74HC574 variants like SN74HC574N or SN74HC574NE4?

Yes, the SN74HC574NG4 is fully pin-compatible with all PDIP-packaged 74HC574 variants including SN74HC574N and SN74HC574NE4. All share identical 20-pin PDIP footprint, pin assignments, electrical specifications, and functional behavior. The "G4" suffix denotes RoHS-compliant lead finish (NiPdAu), but mechanical and electrical interchangeability is maintained across this package family.