STMicroelectronics HCF4555BEY

Overview

HCF4555BEY from STMicroelectronics is a dual 1-of-4 decoder/demultiplexer in CMOS B-series technology, operating from 3 V to 20 V supply, featuring high-level active outputs, symmetrical output characteristics, and quiescent current tested up to 20 V. It implements two independent decoders, each with two select inputs (A/B), one active-high enable (E), and four mutually exclusive outputs (Q0–Q3), used for address decoding and data routing in industrial control logic.

For engineers reviewing the HCF4555BEY datasheet, HCF4555BEY pinout, HCF4555BEY application, or HCF4555BEY equivalent, key selection criteria include supply voltage range (3–20 V), output polarity (high-on-select), propagation delay (70–440 ns), input leakage (≤100 nA at 18 V), and DIP-16 package compatibility with legacy TTL/CMOS systems.

Technical Context

The HCF4555BEY implements two identical, independent binary-to-1-of-4 decoders in a single monolithic CMOS device. Each section decodes A/B select lines into four active-high outputs when E is low; all outputs go low when E is high - enabling cascaded demultiplexing and hierarchical decoding.

It conforms to JEDEC JESD13B B-series CMOS specifications, supports wide VDD operation (3–20 V), delivers symmetrical VOH/VOL (e.g., VOH = 14.95 V at VDD = 15 V), and maintains guaranteed noise margins (≥2.5 V at 15 V) across temperature (−55°C to +125°C).

Key Specifications

Pinout & Package

Package: Plastic Dual In-line Package (DIP-16), 0.3-inch width, through-hole mount per mechanical drawing P001C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 1-of-4 decoder applications.

Compared with CD4555BE and 74HC154N, the HCF4555BEY uniquely combines dual independent decoders, guaranteed I_Q testing up to 20 V, and symmetrical output drive - making it optimal for modular, expandable, and power-critical industrial decode architectures.

Availability

HCF4555BEY is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy system address decoding, 1-of-8 data demultiplexing, and motor phase sequencing requiring stable component supply across extended temperature and voltage ranges.

Supply support for HCF4555BEY 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 analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The HCF4555BEY belongs to the HCF4000B series of radiation-hardened, high-voltage CMOS logic devices engineered for reliability in harsh environments including factory automation and energy infrastructure.

FAQ

What is the maximum recommended supply voltage for continuous operation?

The HCF4555BEY has a recommended operating VDD range of 3 V to 20 V. While its absolute maximum rating is +22 V, sustained operation above 20 V risks exceeding specified quiescent current limits and may compromise long-term reliability per JEDEC JESD13B compliance requirements.

Does the HCF4555BEY support cascading for 1-of-8 or 1-of-16 decoding?

Yes - the datasheet explicitly validates cascading: one HCF4555BEY's outputs drive the Enable inputs of a second unit to build a 1-of-8 decoder, and combining with an HCF4556B extends this to 1-of-16. The truth tables on pages 5–6 confirm functional correctness and timing compatibility.

Are the outputs truly mutually exclusive under all valid input conditions?

Yes - the truth table and functional diagram confirm that only one Q output per decoder section is HIGH when E is LOW and A/B are stable. No race condition or overlap occurs during transitions, as verified by propagation delay symmetry (tPLH ≈ tPHL) and absence of intermediate states in the logic diagram.

Can the HCF4555BEY directly drive LEDs or small relays without external transistors?

No - its output sink/source capability is limited to ±3.0 mA at 15 V (IOL/IOH). Driving even a standard 2 mA LED requires series resistance limiting, and relays typically demand >10 mA. External buffer transistors or dedicated drivers are required for such loads per the DC specs on page 4.