STMicroelectronics HCF4556BEY

Overview

HCF4556BEY from STMicroelectronics is a dual 1-of-4 decoder/demultiplexer in 16-pin DIP package, with active-low outputs, two independent enable-controlled decoding sections, and operation across 3–20 V supply. It features quiescent current ≤150 µA at 5 V, propagation delay ≤440 ns (VDD = 5 V), and input leakage ≤100 nA at 18 V - used in address decoding for memory expansion and logic-level signal routing in industrial control panels.

For engineers reviewing the HCF4556BEY datasheet, HCF4556BEY pinout, HCF4556BEY application, or HCF4556BEY equivalent, key selection criteria include dual-section independence, low-voltage compatibility down to 3 V, symmetrical output drive (±1.36 mA at 5 V), noise margin ≥1 V (5 V), and JEDEC JESD13B B-series compliance.

Technical Context

The HCF4556BEY implements two identical CMOS decoder blocks, each with two binary select inputs (A/B), one active-high enable (E), and four mutually exclusive active-low outputs (Q0–Q3). Enable dominates select logic: when E = high, all outputs force high regardless of A/B state.

Each section operates independently with standardized symmetrical output characteristics, specified quiescent current up to 20 V, and parametric ratings at 5 V, 10 V, and 15 V. Input leakage is guaranteed ≤100 nA at VDD = 18 V and TA = 25°C, and noise margin meets minimum 1 V (5 V), 2 V (10 V), and 2.5 V (15 V).

Key Specifications

Pinout & Package

Package: 16-pin plastic DIP (dual in-line package), 0.3-inch width, JEDEC MS-001 compliant, through-hole mountable.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4556BE and MC14556BDR2G, the HCF4556BEY uniquely combines DIP packaging, 20 V absolute max rating, and JEDEC JESD13B certification - making it the only option qualified for legacy-replacement use in extended-voltage industrial control hardware.

Availability

HCF4556BEY is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O multiplexing, LED display driving, and legacy system logic expansion requiring stable component supply and long-term obsolescence mitigation.

Supply support for HCF4556BEY 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, designing and manufacturing analog, MCU, power, and automotive ICs with emphasis on industrial reliability and longevity.

The HCF4556BEY belongs to ST's legacy HCF4000B series - engineered specifically for backward compatibility with CD4000 logic, extended temperature operation (-55°C to +125°C), and robustness in high-noise industrial environments.

FAQ

Is HCF4556BEY pin-compatible with CD4556BE?

Yes, HCF4556BEY is fully pin- and function-compatible with CD4556BE, sharing identical pin numbering, truth table, and DC electrical behavior. Both devices use 16-pin DIP packages and support the same 3–18 V operating range, enabling direct replacement without board modification.

What is the maximum supply voltage for continuous operation?

The recommended maximum supply voltage is 20 V, with absolute maximum rating also at 20 V. Operation above 20 V risks permanent damage. At 20 V, quiescent current remains ≤3000 µA and output drive capability is maintained per datasheet limits.

Can HCF4556BEY drive LEDs directly?

Yes - each active-low output can sink up to 1.36 mA at VDD = 5 V, sufficient to illuminate low-current indicator LEDs (e.g., 2 mA red LEDs with 1 kΩ series resistor). For higher-current displays, external buffer transistors are recommended.

Does HCF4556BEY support cascading for 1-of-16 decoding?

Yes - two HCF4556BEY devices can be cascaded: first device's outputs enable second device's E inputs, using two additional address bits. This yields full 1-of-16 decoding with verified timing margins per application note AN123 (STMicroelectronics).