Nexperia USA Inc. 74HC574BQX

Overview

74HC574BQX from Nexperia is an 8-bit positive-edge-triggered D-type flip-flop with 3-state outputs, designed for bus-oriented digital systems requiring synchronized data latching and output isolation. It operates across 2.0 V to 6.0 V supply, features independent clock (CP) and active-low output enable (OE), and supports industrial temperature range (−40 °C to +125 °C) in DHVQFN20 package. Used in microcontroller I/O expansion, address/data bus buffering, and programmable logic interface circuits.

For engineers reviewing the 74HC574BQX datasheet, 74HC574BQX pinout, 74HC574BQX application, or 74HC574BQX equivalent, this device serves as a high-noise-immunity, low-power octal register with precise setup/hold timing (tsu = 10 ns, th = 5 ns @ VCC = 6.0 V), fast propagation delay (tpd = 14 ns typ @ VCC = 6.0 V), and robust ESD protection (HBM > 2000 V).

Technical Context

This device implements eight independent D-type flip-flops sharing a common clock input (CP) and a single active-low 3-state output enable (OE). Each flip-flop captures the logic state of its D-input on the LOW-to-HIGH transition of CP, with set-up and hold times strictly enforced relative to that edge.

Output states are either driven HIGH/LOW or placed in high-impedance (Z) mode based solely on OE - independent of clock activity or internal latch state. Input clamp diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors.

Key Specifications

Pinout & Package

DHVQFN20 (SOT764-1) package: 2.5 mm × 4.5 mm × 0.85 mm body, 20-terminal quad flat no-lead with exposed thermal pad (GND-connected per datasheet recommendation); lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HCT574BQX, the 74HC574BQX provides broader supply flexibility and lower static current, while SN74LV574APWR trades voltage range for sub-2 V operation but sacrifices thermal efficiency and package options.

Availability

74HC574BQX is available at Aetrix Electronics and suitable for microcontroller I/O expansion, address/data bus buffering, FPGA configuration interfaces, and digital logic state capture requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for 74HC574BQX 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability logic, analog, and MOSFET solutions for automotive, industrial, and consumer markets.

The 74HC574BQX belongs to Nexperia's 74HC logic family - engineered for low-power, wide-supply digital interfacing in space-constrained industrial control and embedded systems.

FAQ

What is the maximum clock frequency supported by the 74HC574BQX?

The 74HC574BQX supports a maximum clock frequency of 35 MHz at VCC = 6.0 V and CL = 50 pF, verified by propagation delay (tpd = 14 ns typ) and setup/hold timing constraints. At 3.3 V operation, fmax drops to ~20 MHz due to increased tpd (~25 ns), and derating must follow datasheet curves for ambient temperature and load capacitance.

Can the OE pin be toggled while the clock is active?

Yes - OE is fully asynchronous and does not affect internal flip-flop states. Outputs transition to high-impedance within 13 ns (tdis typ @ VCC = 6.0 V) when OE goes HIGH, and return to driven states within 13 ns (ten typ) when OE returns LOW, regardless of CP activity or stored data.

Is the thermal pad on the DHVQFN20 package electrically connected?

Yes - terminal 1 (GND) is the exposed thermal pad, which must be soldered and connected to the system ground plane. The datasheet explicitly states that leaving it floating degrades thermal performance and may cause reliability issues; connection to GND improves θJA by up to 30 °C/W.

How does the 74HC574BQX handle input voltages above VCC?

Input clamp diodes are integrated on all D, CP, and OE pins. When an input exceeds VCC by >0.5 V, current flows through the diode into VCC; therefore, a series current-limiting resistor (e.g., 1 kΩ) must be used to keep IIK ≤ ±20 mA, preventing damage and ensuring predictable logic levels.