NXP Semiconductors 74HCT259BQ,115

Overview

74HCT259BQ,115 from Nexperia is an 8-bit addressable latch with TTL-compatible inputs, operating from 4.5 V to 5.5 V over -40 °C to +125 °C. It supports four functional modes-addressable latch, memory, 3-to-8 demultiplexing, and reset-and provides individual Q0–Q7 outputs with active-HIGH decoding capability. Used in industrial I/O expansion and microcontroller peripheral interfacing where selective bit latching and parallel output control are required.

For engineers reviewing the 74HCT259BQ,115 datasheet, 74HCT259BQ,115 pinout, 74HCT259BQ,115 application, or 74HCT259BQ,115 equivalent, this device delivers deterministic address-selective storage, fast propagation (≤59 ns @ 5 V), low-power CMOS logic with TTL input thresholds, and robust thermal-enhanced DHVQFN16 packaging for high-density PCB layouts.

Technical Context

The 74HCT259BQ,115 implements a synchronous addressable latch architecture using three address lines (A0–A2) to select one of eight internal storage bits, while LE (latch enable, active LOW) controls data capture from D input. Its conditional MR (master reset, active LOW) forces all outputs LOW independently of address or data state.

It integrates a built-in 3-to-8 decoder function: when in demultiplexer mode (MR = LOW, LE = LOW), the addressed Qn follows D while all others drive LOW. Input clamp diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors.

Key Specifications

Pinout & Package

DHVQFN16 package (SOT763-1): 2.5 mm × 3.5 mm × 0.85 mm body, 16-terminal leadless construction with exposed thermal pad (non-soldered by default), optimized for thermal performance and PCB space efficiency in compact embedded designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit addressable latch applications.

Compared with 74HCT259BQ,115, the SO16 and TSSOP variants trade thermal efficiency and board area for assembly simplicity and footprint compatibility-making the DHVQFN version optimal for space- and thermal-constrained industrial controllers, while the alternatives serve legacy layout or manual assembly needs.

Availability

74HCT259BQ,115 is available at Aetrix Electronics and suitable for industrial I/O expansion, microcontroller peripheral interfacing, programmable logic control, and legacy system signal routing requiring stable component supply across extended temperature ranges.

Supply support for 74HCT259BQ,115 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 leading semiconductor manufacturer specializing in high-performance logic, analog, and discrete components, with a focus on reliability, energy efficiency, and automotive-grade qualification.

The 74HCT259BQ,115 belongs to Nexperia's 74HCT logic family, designed specifically for robust 5 V TTL-compatible interfacing in industrial automation, automotive subsystems, and embedded control applications demanding wide temperature operation and low static power.

FAQ

What is the minimum pulse width required on LE for reliable latching?

The minimum LE pulse width is 18 ns at VCC = 4.5 V (−40 °C to +125 °C). This ensures sufficient time for internal metastability resolution and guarantees deterministic capture of D input at the addressed latch location. Shorter pulses may result in undefined output states or partial updates across Q0–Q7.

Can MR and LE be asserted simultaneously, and what is the resulting behavior?

Yes-asserting both MR (LOW) and LE (LOW) places the device in demultiplexer mode, where the addressed Qn follows D while all other outputs remain LOW. MR does not override LE functionality in this configuration; the mode is determined solely by the MR/LE logic combination per Table 4.

Is the exposed thermal pad on the DHVQFN16 package electrically connected?

No-the exposed pad (terminal 1 index area) has no electrical connection. Per Nexperia documentation, it may be left floating or connected to GND for thermal improvement, but soldering is optional and introduces no electrical requirement. PCB land design should follow SOT763-1 mechanical drawings.

How does the 74HCT259BQ,115 handle input voltages exceeding VCC?

Internal clamp diodes on all inputs permit safe operation with VI up to VCC + 0.5 V, provided input current is limited to ±20 mA using external series resistors. This enables direct interfacing with higher-voltage sensors or legacy buses without level translators, as long as current limits are observed per Table 5.