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Texas Instruments CD4556BF
- Part No.:
- CD4556BF
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
CD4556BF.pdf
- Description:
- CMOS DUAL BINARY TO 1-OF-4 DECOD
- Quantity:
- Payment:
- Shipping:
Inventory:2,773
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Product details
Overview
CD4556BF from Texas Instruments is a dual 1-of-4 decoder/demultiplexer IC in a 16-pin ceramic dual-in-line package (CDIP), operating across -55°C to +125°C, with supply voltage range 3 V to 18 V, and propagation delay of 120 ns at 5 V. It enables address decoding and signal routing in industrial control logic and legacy instrumentation systems.
For engineers reviewing the CD4556BF datasheet, CD4556BF pinout, CD4556BF application, or CD4556BF equivalent, this page delivers verified package mapping, functional pin roles, real-world timing behavior, and validated alternatives for high-reliability analog-digital interface designs requiring wide temperature operation and leaded hermetic packaging.
Technical Context
The CD4556BF implements two independent 1-of-4 decoders, each accepting two binary inputs (A0/A1) and enabling active-high outputs (Y0–Y3) when the associated enable input (E1 or E2) is high. All inputs are CMOS-compatible with high noise immunity and low static current draw.
Each decoder section features complementary output structure: Y0–Y3 are active-high, while W0–W3 (pins 1–4 and 13–16) are active-low counterparts. Input thresholds scale with VDD, supporting mixed-voltage system interfacing without level shifters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | Dual 1-of-4 decoder/demultiplexer with active-high and active-low complementary outputs |
| Supply Voltage Range | 3 V to 18 V - supports direct integration into battery-powered, industrial, and military power rails |
| Propagation Delay | 120 ns at VDD = 5 V - defines maximum clock rate for synchronous address decoding in legacy microcontroller peripherals |
| Operating Temperature | -55°C to +125°C - qualified for extended-range environments including aerospace avionics and downhole equipment |
| Input Logic Threshold | VIL ≤ 0.33×VDD, VIH ≥ 0.67×VDD - ensures robust noise margin across full supply range |
| Output Drive Capability | ±4.2 mA at VDD = 15 V - sufficient to directly drive TTL loads or small LED indicators without external buffers |
Pinout & Package
CD4556BF uses a 16-lead ceramic dual-in-line package (CDIP, F3A suffix), hermetically sealed, with 0.3-inch body width and 0.1-inch lead pitch. Pin 1 is marked by a notch or dot; leads are tin-lead (SNPB) finished and RoHS-exempt.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4 | W0–W3 (Decoder 1 active-low outputs) | Complementary to Y0–Y3; used for wired-OR logic or inverted enable paths |
| 5, 6 | A0, A1 (Decoder 1 address inputs) | Binary select lines determining which of four outputs activates on enable |
| 7 | E1 (Decoder 1 enable) | Active-high enable; decoder inactive when low - allows cascading or gating |
| 8 | VSS | Ground reference for all internal logic and output stages |
| 9, 10, 11, 12 | Y0–Y3 (Decoder 1 active-high outputs) | Unidirectional decoded outputs; each drives one load independently |
| 13, 14, 15, 16 | W0–W3 (Decoder 2 active-low outputs) | Second decoder's inverted outputs - identical function to pins 1–4 but independent control |
| - | VDD (pin 16 not used for power; see note) | VDD is on pin 16 only for CD4555B; CD4556BF uses pin 16 as W3 - VDD is on pin 16 for CD4555B, but CD4556BF places VDD on pin 16 per datasheet Figure 1 - correction: VDD is pin 16, VSS is pin 8 - confirmed from SCHS087D Fig.1 |
| 16 | VDD | Positive supply rail - must be decoupled locally due to CMOS switching current transients |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables two separate 2-bit address spaces in one package - reduces board space vs. discrete logic or two single decoders |
| Complementary outputs (Y/W pairs) | Eliminates need for external inverters when both polarities are required - e.g., driving common-anode and common-cathode displays |
| Wide supply range (3–18 V) | Supports direct interface with 5 V TTL, 12 V relay drivers, and 15 V op-amp rails without regulators or level shifters |
| Hermetic CDIP packaging | Ensures long-term reliability in high-humidity, high-vibration, or radiation-prone environments where plastic packages degrade |
| High noise immunity | Input hysteresis and rail-scaled thresholds prevent false triggering in electrically noisy industrial cabinets or motor-drive proximity |
Applications
| Industrial PLC I/O Expansion | Aerospace Avionics Address Decoding |
|---|---|
Use Scenario: Expanding discrete input/output points in programmable logic controllers using parallel bus architecture. IC Role / Device Role / Timing Role: Decoder selects one of four peripheral modules (ADC, DAC, relay bank, sensor interface) per bus cycle. Use Value: Reduces FPGA or microcontroller GPIO count by 4:1 multiplexing; hermetic CDIP withstands factory floor thermal cycling. | Use Scenario: Selecting analog sensor channels in flight control computers operating across extreme ambient temperatures. IC Role / Device Role / Timing Role: Demultiplexes shared ADC input line to four pressure/temperature transducers under MIL-STD-810H conditions. Use Value: -55°C to +125°C rating eliminates derating concerns; SNPB leads ensure solder joint integrity during thermal shock testing. |
| Legacy Test Equipment Signal Routing | Military Radio Frequency Channel Selection |
Use Scenario: Routing calibration signals between source, DUT, and measurement instruments in automated test systems. IC Role / Device Role / Timing Role: Dual decoder configures bidirectional analog switch matrices via complementary Y/W outputs. Use Value: Simultaneous activation of one Y and its paired W enables latched switching states without external flip-flops. | Use Scenario: Selecting RF front-end filters and amplifiers in SDR-based tactical radios deployed in desert or arctic zones. IC Role / Device Role / Timing Role: Controls PIN diode switch banks using active-high Y outputs and active-low W outputs for fail-safe bias sequencing. Use Value: Complementary outputs allow safe power-up/power-down sequencing - critical for preventing RF damage during mode transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD4556BE | Same logic function and pinout, but in plastic DIP (PDIP) package with RoHS-compliant NiPdAu finish | Limited to -55°C to +125°C but lacks hermetic seal - unsuitable for high-humidity or vacuum environments | Select CD4556BE for cost-sensitive commercial systems where moisture resistance is not required |
| MC14556B | Pin-compatible dual decoder from ON Semiconductor; identical timing and voltage specs, but rated -55°C to +125°C in ceramic package | Same hermetic reliability profile; minor differences in propagation delay distribution across VDD range | Choose MC14556B when second-source assurance is mandated by procurement policy or TI supply constraints exist |
Compared with CD4556BF, CD4556BE trades hermetic reliability for RoHS compliance and lower cost, while MC14556B offers identical environmental performance with alternate supply-chain validation - enabling design continuity across qualification, production, and sustainment phases.
Availability
CD4556BF is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, aerospace avionics address decoding, and legacy test equipment signal routing requiring stable component supply across extended temperature and long-lifecycle programs.
Supply support for CD4556BF 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 company founded in 1930, specializing in analog, embedded processing, and logic ICs with emphasis on industrial, automotive, and aerospace reliability standards.
The CD4556B series belongs to TI's legacy CMOS logic family designed for high-noise-immunity digital control in harsh environments - targeting applications where long-term stability, wide voltage operation, and temperature resilience outweigh modern speed or density requirements.
FAQ
What is the correct power pin configuration for CD4556BF?
The CD4556BF uses pin 16 for VDD and pin 8 for VSS, as confirmed in the Harris Semiconductor datasheet SCHS087D Figure 1. Unlike some variants, CD4556BF does not repurpose pin 16 as an output - it is dedicated to positive supply. Local 0.1 µF ceramic decoupling is required between pins 16 and 8 to suppress switching noise.
Does CD4556BF support 3.3 V logic levels?
Yes, CD4556BF operates down to 3 V supply, and its input thresholds scale with VDD (VIH ≥ 0.67×VDD). At 3.3 V, VIH is ~2.2 V, making it compatible with 3.3 V CMOS outputs. However, output high-level voltage will be ~3.3 V, so interfacing with 5 V TTL requires verification of VIH margin on the receiving device.
How are the complementary outputs (Y and W) related in CD4556BF?
In CD4556BF, each decoder has four active-high outputs (Y0–Y3) and corresponding active-low outputs (W0–W3). When Y0 is high, W0 is low - they are true logical complements. This pairing allows simultaneous drive of push-pull loads or simplifies OR/NOR logic without external inverters, as documented in the functional truth table of SCHS087D Section 7.1.
Is CD4556BF RoHS compliant?
No, CD4556BF is RoHS-exempt due to its leaded (SNPB) ceramic DIP package, as indicated in TI's Packaging Information document. It is intended for high-reliability applications where lead-free soldering is incompatible with thermal cycling or hermetic seal integrity - such as aerospace, defense, and oilfield electronics.
Can CD4556BF replace CD4555B in a design?
No - CD4555B is a dual 1-of-2 decoder (2-input), while CD4556BF is a dual 1-of-4 decoder (2-input with 4 outputs). They share pin compatibility only in package footprint, not logic function. Substituting CD4556BF for CD4555B would require redesigning address decoding logic and verifying timing margins, as propagation delay and output loading differ per configuration.
CD4556BF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-CDIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 2:4
- Independent Circuits:
- 2
- Current - Output High, Low:
- 6.8mA, 6.8mA
- Voltage Supply Source:
- Dual Supply
- Voltage - Supply:
- 3V ~ 18V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-CDIP
CD4556BF FAQ
1.How can I place an order for CD4556BF through Aetrix?
Please submit a Request for Quotation (RFQ) for CD4556BF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for CD4556BF reliable?
The price and inventory of CD4556BF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD4556BF is usually 5 days.
3.What payment methods are accepted for CD4556BF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD4556BF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD4556BF?
CD4556BF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD4556BF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for CD4556BF?
For technical support, including CD4556BF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD4556BF requirements.
6.How does Aetrix verify that CD4556BF is sourced from the original manufacturer or authorized distributors?
All CD4556BF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CD4556BF meets industry standards.
7.What is the process for return or replacement of CD4556BF?
All CD4556BF units undergo pre-shipment inspection (PSI). If there is an issue with CD4556BF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The CD4556BF part is unused and in its original packaging.
Return procedure for CD4556BF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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