STMicroelectronics M74HC259B1R

Overview

M74HC259B1R from STMicroelectronics is a high-speed CMOS 8-bit addressable latch with active-low enable and conditional clear, operating from 2 V to 6 V supply. It features 3 address inputs (A/B/C), single data input (D), 8 independent latch outputs (Q0–Q7), and delivers tPD = 20 ns (typ.) at VCC = 6 V, ICC ≤ 4 µA (max.) at 25 °C, and symmetrical output drive of ±4 mA (min.). It is used in digital control logic for selective memory storage in industrial I/O expanders and programmable logic interfaces.

For engineers reviewing the M74HC259B1R datasheet, M74HC259B1R pinout, M74HC259B1R application, or M74HC259B1R equivalent, this device serves as an address-selectable storage element with demultiplexer functionality, requiring precise timing validation for ENABLE and CLEAR pulse widths, setup/hold timing on address/data lines, and voltage-level compatibility across 2–6 V operation.

Technical Context

The M74HC259B1R implements a 3-to-8 address decoder combined with eight individually addressable D-type latches. Its logic enables data capture on the rising edge of ENABLE (active low), while CLEAR (active low) conditionally resets all latches - fully when ENABLE is high, or only unaddressed latches when ENABLE is low.

All inputs include ESD protection (HBM: 1.5 kV, CDM: 1 kV), and outputs exhibit balanced propagation delays (tPLH ≈ tPHL) and symmetrical impedance (|IOH| = IOL ≥ 4 mA). The device operates across -55 °C to +125 °C and supports both SO16 and TSSOP16 packages with automotive-grade variants available.

Key Specifications

Pinout & Package

Package: SO16 (Small Outline Integrated Circuit, 16-pin, 1.27 mm pitch, body width 3.9 mm). Compliant with JEDEC MS-012, RoHS and ECOPACK® standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC259N and 74LVX259M, the M74HC259B1R uniquely supports full -55 °C to +125 °C operation with AEC-Q100-compliant variants, maintains 2–6 V compatibility for legacy system integration, and delivers stronger output drive for direct TTL loading - making it optimal for ruggedized industrial and automotive-adjacent control modules.

Availability

M74HC259B1R is available at Aetrix Electronics and suitable for industrial I/O expansion, programmable logic controller (PLC) output modules, test equipment signal routing, and legacy bus interface adapters requiring stable component supply across extended temperature ranges.

Supply support for M74HC259B1R 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The M74HC259 belongs to ST's high-reliability HC logic family, engineered for robust performance in harsh environments - emphasizing wide voltage tolerance, noise immunity, and extended temperature operation for industrial control and automation systems.

FAQ

What is the maximum clock frequency supported by M74HC259B1R?

The M74HC259B1R does not operate on a clock signal but responds to edge-triggered ENABLE pulses. Its minimum ENABLE pulse width is 6 ns at VCC = 6 V, supporting effective update rates up to ~80 MHz in ideal conditions. Real-world maximum rate depends on address/data setup/hold times (e.g., tS(D) = 3 ns min. at 6 V) and PCB layout-induced skew.

Can M74HC259B1R drive LEDs directly?

Yes - each output can sink or source up to 4 mA (min.) continuously. At VCC = 5 V, driving a typical red LED (VF ≈ 1.8 V) with a 470 Ω series resistor draws ~6.8 mA, exceeding absolute max ratings. Safe direct drive requires limiting current to ≤4 mA (e.g., 820 Ω resistor), or using external transistors for higher-current loads.

How does the CLEAR input behave when ENABLE is low?

When ENABLE is low, CLEAR performs selective reset: only the unaddressed latches are cleared to logic low; the addressed latch follows the D input. This enables simultaneous data loading and background reset - e.g., updating one channel while zeroing others in a single bus transaction.

Is M74HC259B1R pin-compatible with older 74LS259 devices?

Yes - it is pin- and function-compatible with the 74 series 259 family, including 74LS259 and 74ALS259. However, M74HC259B1R uses CMOS input thresholds (VIH ≥ 3.15 V at VCC = 4.5 V) versus TTL thresholds (VIH ≥ 2.0 V), so direct replacement requires verifying driving source logic levels meet HC input specifications.