Texas Instruments CD4556BF3A

Overview

CD4556BF3A from Texas Instruments is a dual 1-of-4 decoder/demultiplexer IC in a hermetic 16-pin CDIP (J) package, operating across -55°C to +125°C, with supply voltage range 3 V to 18 V, and TTL/CMOS-compatible inputs. It functions as a logic-level address decoder in industrial control panels requiring high-reliability discrete logic.

For engineers reviewing the CD4556BF3A datasheet, CD4556BF3A pinout, CD4556BF3A application, or CD4556BF3A equivalent, this device serves as a radiation-tolerant, wide-temperature-range decoding solution for legacy aerospace avionics, military test equipment, and hardened instrumentation where leaded ceramic packaging and SNPB finish are mandated.

Technical Context

The CD4556BF3A implements two independent 1-of-4 decoders, each with active-high outputs and active-low enable inputs. Each decoder accepts two binary address inputs (A0, A1) and selects one of four outputs (Y0–Y3) when enabled - no internal latching or clocking is present.

It belongs to the CD4000B series of CMOS logic devices, featuring high noise immunity (≥45% V_DD), low static current (<100 nA at 18 V), and symmetrical output drive capability (±4.2 mA at 15 V). Input thresholds scale linearly with V_DD, enabling robust operation across its full 3–18 V supply range.

Key Specifications

Pinout & Package

CD4556BF3A uses a 16-lead ceramic dual-in-line package (CDIP, J suffix), hermetically sealed with SNPB (tin-lead) leads, rated for -55°C to +125°C operation and compatible with wave soldering processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4556BE and CD4556BM96, the CD4556BF3A uniquely combines military-grade temperature range, hermetic ceramic packaging, and SNPB leads - making it the sole option for repair, sustainment, or new design-in where legacy process compliance and environmental ruggedness are mandatory.

Availability

CD4556BF3A is available at Aetrix Electronics and suitable for avionics data bus interfaces, military test equipment, and industrial PLC I/O expansion requiring stable component supply across extended temperature ranges and legacy soldering compatibility.

Supply support for CD4556BF3A 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic technologies, with over 90 years of innovation in high-reliability components.

The CD4000B series - including CD4556BF3A - was designed for radiation-tolerant, wide-temperature industrial and defense applications where CMOS logic stability, low power, and process longevity are essential.

FAQ

What is the maximum operating frequency supported by CD4556BF3A?

The CD4556BF3A does not specify a maximum clock or toggle frequency because it is a combinational logic device without internal clocking. Its usable speed is governed by propagation delay: 120 ns maximum at V_DD = 15 V, supporting reliable operation in address decode paths up to ~8 MHz. The CD4556BF3A performance remains stable across its full -55°C to +125°C range.

Is CD4556BF3A pin-compatible with CD4556BE?

Yes, CD4556BF3A and CD4556BE share identical pinout, logic function, and DC electrical specifications. The difference lies solely in packaging: CD4556BF3A uses hermetic ceramic DIP (CDIP/J) with SNPB leads, while CD4556BE uses plastic DIP (PDIP/N) with RoHS-compliant NIPDAU finish. Mechanical fit is identical, but soldering and environmental qualification differ.

Does CD4556BF3A include internal pull-up or pull-down resistors on inputs?

No, CD4556BF3A has no internal pull-up or pull-down resistors on any input. All inputs (A0, A1, EN1̅, EN2̅) are CMOS gates with high impedance and require externally defined logic states. Floating inputs will cause unpredictable output behavior and increased supply current - external termination is mandatory for robust operation.

Can CD4556BF3A drive LEDs directly?

Yes, CD4556BF3A can drive standard indicator LEDs directly: each output delivers ±4.2 mA at V_DD = 15 V, sufficient for 2–5 mA LED biasing with appropriate series resistance. For example, at V_DD = 12 V and V_F = 2.0 V, a 2.2 kΩ resistor limits current to ~4.5 mA - well within CD4556BF3A's output capability and safe for continuous operation.

What is the meaning of the 'F3A' suffix in CD4556BF3A?

The 'F3A' suffix denotes the hermetic 16-pin ceramic dual-in-line package (CDIP) variant with tin-lead (SNPB) leads, per Texas Instruments' packaging nomenclature. It identifies the device as part of the military-qualified catalog family and confirms compliance with MIL-PRF-38535 Class K or equivalent screening for high-reliability applications.