NXP Semiconductors N74F574D,623

Overview

N74F574D,623 from Philips Semiconductors is an octal D-type edge-triggered flip-flop with 3-State outputs, designed for bus-oriented microprocessor interface applications. It features a 180 MHz maximum clock frequency, 5.0 ns typical propagation delay (CP to Qn), and active-Low Output Enable (OE) controlling all eight outputs independently of clock operation. The device operates at 5 V ±10% over 0°C to +70°C and uses a broadside pinout in a 20-lead plastic SO package (SOT163-1) to simplify PCB layout.

For engineers reviewing the N74F574D,623 datasheet, N74F574D,623 pinout, N74F574D,623 application, or N74F574D,623 equivalent, key selection considerations include its rising-edge clock triggering, 24 mA low-level output drive capability, glitch-free 3-State behavior during power transitions, and compatibility with TTL/CMOS logic families in high-speed data latching and bus buffering roles.

Technical Context

The N74F574D,623 implements fully edge-triggered storage: each D input's state one setup time before the Low-to-High clock transition is captured and held at the corresponding Q output. Its dual-control architecture separates timing (CP) from bus access (OE), enabling independent register update and output gating.

All eight 3-State outputs share a common active-Low OE signal but remain electrically isolated from latch operation-outputs enter high-impedance "off" state when OE is High, regardless of CP or Q state. Input loading is standardized at 1.0 FAST Unit Load (20 µA High / 0.6 mA Low), and outputs drive up to 24 mA Low / 3 mA High into heavily loaded buses or MOS memory interfaces.

Key Specifications

Pinout & Package

Package: 20-lead plastic small outline (SO), body width 7.5 mm (SOT163-1), surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F574N and 74ACT574PC, the N74F574D,623 offers optimized surface-mount integration in commercial temperature range systems, balancing speed, drive strength, and legacy TTL compatibility without requiring layout or timing redesign.

Availability

N74F574D,623 is available at Aetrix Electronics and suitable for microprocessor bus interfacing, parallel I/O expansion, industrial data acquisition, and legacy system bus buffering requiring stable component supply and long-term sourcing continuity.

Supply support for N74F574D,623 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

Philips Semiconductors (now NXP Semiconductors) is a pioneer in bipolar TTL logic design, delivering high-speed, industrial-grade interface ICs since the 1970s.

The 74F logic family-including N74F574D,623-was engineered for microprocessor system integration, emphasizing fast propagation, robust 3-State bus driving, and broadside pinouts to reduce PCB complexity in commercial computing and control applications.

FAQ

What is the clock input behavior of the N74F574D,623?

The N74F574D,623 uses a positive-edge-triggered clock (CP) input: data present at each Dn input one setup time (2.5 ns min) before the Low-to-High transition is transferred synchronously to the corresponding Qn output. Hold time is 0 ns, meaning data may change immediately after the clock edge without affecting latched value. This behavior makes N74F574D,623 ideal for precise timing-critical data capture in microprocessor systems.

How does the Output Enable (OE) pin interact with the clock and stored data in N74F574D,623?

In N74F574D,623, the OE pin operates asynchronously and independently of CP and internal register state. When OE is Low, the currently latched Q values appear on outputs; when OE is High, all Q outputs enter high-impedance state regardless of CP activity or stored data. This decoupling allows bus sharing without disturbing register contents-critical for N74F574D,623 use in multi-master systems.

What is the maximum output drive capability of N74F574D,623, and how does it affect bus loading?

N74F574D,623 delivers 24 mA sink current (IOL) and –3 mA source current (IOH) per output, supporting up to 40 FAST Unit Loads in Low state and 150 in High state. This enables direct connection to heavily loaded 5 V TTL buses without external buffers. For N74F574D,623 deployments, this means up to 20 standard TTL inputs or 5–8 74F-series loads can be driven per output, simplifying system-level bus design.

Is N74F574D,623 pin-compatible with other 74F-series octal D flip-flops like 74F374?

Yes-N74F574D,623 is functionally identical to 74F374 but features a broadside pinout (inputs and outputs on opposite sides of package), whereas 74F374 uses standard pinout. Both share identical logic function, timing, and DC specs. The N74F574D,623 pin mapping matches 74F374 only in signal assignment-not physical location-so PCB layout must follow SOT163-1 pinout, not legacy DIP layouts.

Does N74F574D,623 support hot insertion or power sequencing without risk of bus contention?

Yes-N74F574D,623 guarantees glitch-free 3-State outputs during power-up and power-down transitions. When VCC ramps, outputs remain in high-impedance state until supply stabilizes, preventing unintended bus driving. This behavior is intrinsic to the internal circuit design and requires no external reset or control sequencing-making N74F574D,623 safe for use in modular or field-upgradeable systems.