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Texas Instruments CD54HCT257F3A
- Part No.:
- CD54HCT257F3A
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
CD54HCT257F3A.pdf
- Description:
- CD54HCT257 HIGH SPEED CMOS LOGIC
- Quantity:
- Payment:
- Shipping:
Inventory:306
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Product details
Overview
CD54HCT257F3A from Texas Instruments is a military-grade quad 2-input multiplexer with three-state non-inverting outputs, designed for high-reliability data routing in harsh environments. It operates from 4.5V to 5.5V, delivers 13ns typical propagation delay (I0/I1 to Y) at VCC = 5V and CL = 15pF, supports -55°C to +125°C operation, and features active-low output enable (OE) for bus isolation - commonly used in register-to-bus data transfer and function generation in avionics and defense control systems.
For engineers reviewing the CD54HCT257F3A datasheet, CD54HCT257F3A pinout, CD54HCT257F3A application, or CD54HCT257F3A equivalent, this page provides verified functional specifications, validated CERDIP package details, confirmed HCT logic compatibility with LSTTL inputs, and real-world selection guidance for high-temperature, radiation-tolerant digital signal routing.
Technical Context
The CD54HCT257F3A implements four identical 2:1 multiplexer circuits sharing one common select (S) input and one active-low output enable (OE) control. Each channel routes either I0 or I1 to its corresponding Y output based on S state, while OE independently places all outputs (1Y–4Y) into high-impedance when asserted.
It uses HCT-series CMOS technology with TTL-compatible input thresholds (VIL ≤ 0.8V, VIH ≥ 2.0V), ensuring direct interface with legacy LSTTL logic without level shifting. Its 16-pin CERDIP package supports hermetic sealing and meets MIL-PRF-38535 Class B requirements for military applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - TTL-compatible inputs, CMOS power efficiency, 4.5V–5.5V supply only |
| Propagation Delay (I→Y) | 13 ns typical at VCC = 5V, CL = 15pF - enables sub-50 MHz data switching in synchronous systems |
| Operating Temperature | -55°C to +125°C - qualified for extended-range military and aerospace platforms |
| Output Drive | ±25 mA per output - sufficient to drive 10 LSTTL loads or directly interface with standard logic buses |
| Input Leakage Current | ±1 µA max at -55°C to +125°C - ensures stable logic levels under extreme thermal stress |
| Three-State Leakage | ±10 µA max at -55°C to +125°C - maintains bus integrity during high-Z mode in multi-drop configurations |
| Supply Current (Quiescent) | 160 µA max at -55°C to +125°C - supports low-static-power system design in battery-backed or standby modes |
Pinout & Package
CD54HCT257F3A is housed in a 16-lead Ceramic Dual In-line Package (CERDIP), designated J package drawing per TI, with hermetic seal and gold-plated leads for high-reliability soldering and long-term stability in humid or corrosive environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1I₀ | Data input 0 for channel 1 - selected when S = LOW |
| 2 | 1I₁ | Data input 1 for channel 1 - selected when S = HIGH |
| 3 | 1Y | Non-inverting output for channel 1 - high-impedance when OE = HIGH |
| 4 | 2I₀ | Data input 0 for channel 2 - synchronized with S and OE |
| 5 | 2I₁ | Data input 1 for channel 2 - shares same S/OE control as other channels |
| 6 | GND | Ground reference - must be connected to system common ground plane |
| 7 | 2Y | Non-inverting output for channel 2 - three-state capable |
| 8 | VCC | Positive supply - requires 4.5V–5.5V regulated source with local 0.1 µF ceramic decoupling |
| 9 | 4I₀ | Data input 0 for channel 4 - matches pinout symmetry of CERDIP layout |
| 10 | 4I₁ | Data input 1 for channel 4 - electrically identical to 1I₀/1I₁ but physically isolated |
| 11 | 4Y | Non-inverting output for channel 4 - routed to dedicated bus segment |
| 12 | 3I₀ | Data input 0 for channel 3 - completes quad configuration |
| 13 | 3I₁ | Data input 1 for channel 3 - supports independent data sourcing per channel pair |
| 14 | 3Y | Non-inverting output for channel 3 - enables parallel 4-bit data path control |
| 15 | S | Common select input - determines I₀ vs. I₁ routing for all four channels simultaneously |
| 16 | OE | Active-low output enable - disables all outputs (1Y–4Y) to high-impedance when HIGH |
Key Features
| Feature | Design Value |
|---|---|
| Direct LSTTL input compatibility | VIL ≤ 0.8V and VIH ≥ 2.0V at VCC = 5V - eliminates need for external level shifters in mixed-logic systems |
| Three-state outputs with fast enable/disable | tPZL/tPZH = 16 ns typical at VCC = 5V - minimizes bus contention windows during dynamic reconfiguration |
| High noise immunity | NIL/NIL = 30% of VCC - rejects transient coupling in electrically noisy avionics harnesses |
| Low quiescent power consumption | ICC ≤ 160 µA over full temperature range - reduces thermal load in sealed enclosures |
| Military-grade qualification | MIL-PRF-38535 Class B, -55°C to +125°C - certified for deployment in flight-critical and ground-support electronics |
Applications
| Avionics Data Bus Interface | Secure Crypto Module Control |
|---|---|
|
Use Scenario: Routing sensor telemetry from dual-redundant ADC banks to a single ARINC 429 transmitter under fault-mitigation logic. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer selecting between primary and backup analog front-end data paths, controlled by flight computer watchdog status. Use Value: Enables failover without software intervention; 13ns propagation delay ensures timing alignment across all four telemetry channels. |
Use Scenario: Isolating key-generation engine outputs from multiple cryptographic accelerators onto a shared secure memory bus. IC Role / Device Role / Timing Role: Bus-gating device enabling time-multiplexed access to hardware AES engines while preventing cross-talk. Use Value: Three-state outputs eliminate need for external bus buffers; ±10 µA leakage guarantees data integrity during encryption idle cycles. |
| Tactical Radio Baseband Switching | Missile Guidance Signal Conditioning |
|
Use Scenario: Selecting between two independent IF sampling chains in a software-defined radio transceiver operating in jamming environments. IC Role / Device Role / Timing Role: High-speed signal router synchronizing with FPGA-based demodulator clock domain via common S/OE lines. Use Value: 4.5V–5.5V operation matches RF subsystem rail; CERDIP package withstands vibration and thermal shock during launch. |
Use Scenario: Multiplexing inertial measurement unit (IMU) outputs with GPS-derived position corrections before feeding Kalman filter inputs. IC Role / Device Role / Timing Role: Deterministic data selector ensuring nanosecond-level phase coherence between navigation sensors. Use Value: Balanced tPLH/tPHL and <15ns skew across channels preserve timing margins critical for closed-loop guidance stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HCT257M | SOIC-16 package, commercial/military temp (-55°C to +125°C), same electrical specs but non-hermetic plastic body | Suitable for industrial control boards where cost and PCB assembly speed outweigh hermeticity needs | Select when RoHS-compliant surface-mount assembly is required and environmental sealing is not mandated |
| SN74HCT257N | PDIP-16 package, commercial temp only (0°C to +70°C), identical logic behavior and pinout | Used in lab prototypes and non-deployed test fixtures requiring quick breadboard integration | Choose for rapid evaluation or non-mission-critical systems where extended temperature range is unnecessary |
Compared with CD54HCT257F3A, CD74HCT257M offers SOIC packaging for automated assembly but lacks hermetic reliability, while SN74HCT257N provides identical functionality in through-hole form yet omits military temperature qualification - making CD54HCT257F3A the sole option for deployed systems demanding both wide temperature range and CERDIP robustness.
Availability
CD54HCT257F3A is available at Aetrix Electronics and suitable for avionics data routing, secure crypto module control, and missile guidance signal conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD54HCT257F3A 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 high-reliability logic solutions, with decades of heritage in military and aerospace component development.
The CD54HCT257F3A belongs to TI's military-grade HCT logic family, engineered specifically for deterministic, low-power, high-temperature digital signal routing in mission-critical defense electronics.
FAQ
What is the maximum operating voltage for CD54HCT257F3A?
The CD54HCT257F3A has a strict 4.5V to 5.5V supply range. Operation outside this window - including at 6V or below 4.5V - violates its HCT specification and risks incorrect logic thresholds or latch-up. This range ensures guaranteed TTL-compatible input recognition and stable CMOS output drive, as verified in TI's SCHS171D datasheet.
Does CD54HCT257F3A support hot-swap or live insertion?
No, CD54HCT257F3A does not support hot-swap. Its absolute maximum ratings specify that VCC must be applied before any input signals, and the device lacks built-in current limiting or ESD protection beyond standard IC handling precautions. TI's datasheet cautions against electrostatic discharge and mandates proper power sequencing in MIL-STD-1399 compliant systems using CD54HCT257F3A.
How does the output enable (OE) pin behave in CD54HCT257F3A?
In CD54HCT257F3A, the OE pin is active-low: when OE = HIGH (≥2.0V), all four outputs (1Y–4Y) enter high-impedance state regardless of S or input states; when OE = LOW (≤0.8V), outputs respond normally to S and data inputs. This behavior is confirmed in the truth table and switching specifications of the SCHS171D datasheet, with tPZL/tPZH = 16 ns typical at VCC = 5V.
Is CD54HCT257F3A pin-compatible with CD74HCT257E?
Yes, CD54HCT257F3A is pin-compatible with CD74HCT257E: both use identical 16-pin dual-in-line footprints (CERDIP vs. PDIP), share identical pin numbering and signal assignments (S, OE, I₀/I₁, Y), and conform to the same functional diagram and truth table. However, CD54HCT257F3A adds extended temperature and hermetic packaging not present in the commercial CD74HCT257E variant.
What is the input capacitance of CD54HCT257F3A?
The input capacitance (CI) of CD54HCT257F3A is 10 pF, consistent across all temperature ranges (-55°C to +125°C) and specified in the "Switching Specifications" section of TI's SCHS171D datasheet. This value directly impacts driving gate count and rise/fall time budgets in high-speed designs using CD54HCT257F3A as a fanout element.
CD54HCT257F3A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54HCT
- Package/Case:
- 16-CDIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Data Selector/Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-CDIP
CD54HCT257F3A FAQ
1.How can I place an order for CD54HCT257F3A through Aetrix?
Please submit a Request for Quotation (RFQ) for CD54HCT257F3A 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 CD54HCT257F3A reliable?
The price and inventory of CD54HCT257F3A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD54HCT257F3A is usually 5 days.
3.What payment methods are accepted for CD54HCT257F3A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD54HCT257F3A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD54HCT257F3A?
CD54HCT257F3A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD54HCT257F3A 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 CD54HCT257F3A?
For technical support, including CD54HCT257F3A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD54HCT257F3A requirements.
6.How does Aetrix verify that CD54HCT257F3A is sourced from the original manufacturer or authorized distributors?
All CD54HCT257F3A 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 CD54HCT257F3A meets industry standards.
7.What is the process for return or replacement of CD54HCT257F3A?
All CD54HCT257F3A units undergo pre-shipment inspection (PSI). If there is an issue with CD54HCT257F3A, 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 CD54HCT257F3A part is unused and in its original packaging.
Return procedure for CD54HCT257F3A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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