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Texas Instruments SN54HC257J
- Part No.:
- SN54HC257J
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SN54HC257J.pdf
- Description:
- 54HC257 QUAD 2-LINE TO 1-LINE DA
- Quantity:
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Inventory:1,092
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Product details
Overview
SN54HC257J from Texas Instruments is a high-speed CMOS quad 2-line-to-1-line data selector/multiplexer with 3-state outputs, designed for bus interface in military-grade systems. It operates across 2 V to 6 V, delivers ±6-mA output drive at 5 V, exhibits typical propagation delay of 9 ns at 6 V, and supports −55°C to 125°C operation in CDIP package - enabling reliable signal routing in avionics and ruggedized control subsystems.
For engineers reviewing the SN54HC257J datasheet, SN54HC257J pinout, SN54HC257J application, or SN54HC257J equivalent, this page provides verified functional identity, military temperature-range performance data, 3-state enable timing (ten/tdis), bus-isolation design guidance, and validated drop-in alternatives for legacy system upgrades and radiation-tolerant board designs.
Technical Context
The SN54HC257J implements four independent 2:1 multiplexers sharing a common output-enable (G) input and select line (A/B). Each channel selects between two inputs (A or B) and drives a high-impedance 3-state output (Y), supporting bidirectional bus arbitration without contention. Its TTL-compatible output drive (15 LSTTL loads) and low ICC (80 µA max) enable integration into mixed-voltage, low-power military backplanes.
Logic-level translation is supported via wide VCC range (2–6 V), with VIH/VIL thresholds scaling proportionally. Input transition time limits (400 ns at 6 V) and guaranteed 3-state isolation (IOZ ≤ ±0.5 µA) ensure robust noise immunity and clean bus release during power sequencing - critical for fault-tolerant computing architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - enables direct interfacing with 3.3 V and 5 V logic domains without level shifters. |
| Propagation Delay (tpd) | 9 ns typical at VCC = 6 V, CL = 50 pF - ensures sub-10 ns timing margin for 50 MHz bus cycles. |
| Output Drive | ±6 mA at 5 V - sufficient to drive 15 LSTTL loads, supporting legacy TTL bus loading requirements. |
| Quiescent Current (ICC) | 80 µA maximum - minimizes standby power in battery-backed or thermally constrained military modules. |
| Operating Temperature | −55°C to +125°C - qualified per MIL-PRF-38535 for use in extended-environment avionics and ground vehicle ECUs. |
| 3-State Enable Time (ten) | 13 ns maximum at VCC = 6 V - guarantees fast bus release for time-critical arbitration protocols. |
| Input Leakage Current | ±1 µA maximum - prevents unintended logic transitions in high-impedance or floating-bus configurations. |
Pinout & Package
SN54HC257J is housed in a 16-pin Ceramic Dual In-line Package (CDIP-J), hermetically sealed for moisture resistance and thermal stability in harsh environments. Pin spacing is 0.1 inch (2.54 mm), with standard DIP footprint compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 2A, 3A, 4A | Data Input A | First input source per multiplexer channel; tied to primary data path in bus selection. |
| 1B, 2B, 3B, 4B | Data Input B | Secondary input source per channel; enables redundant or alternate signal routing. |
| 1Y, 2Y, 3Y, 4Y | 3-State Output | Active-high output when G = L and A/B selects corresponding input; high-Z when G = H. |
| A/B | Select Control | Common 1-bit bus-wide select line determining whether A or B inputs appear at Y outputs. |
| G | Output Enable | Active-low global enable; must be pulled to VCC via resistor during power-up to guarantee high-Z state. |
| VCC | Power Supply | Positive supply rail (2–6 V); decoupling capacitor required within 10 mm for noise suppression. |
| GND | Ground Reference | Signal and power return; requires low-inductance connection to minimize ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Wide-Voltage Operation | 2 V to 6 V supply range allows interoperability across 3.3 V microcontrollers and 5 V legacy peripherals without voltage translation. |
| High-Current 3-State Outputs | ±6 mA drive capability at 5 V ensures robust signal integrity on loaded buses while maintaining high-impedance isolation when disabled. |
| Low Power Consumption | 80 µA max ICC enables long-term operation in power-constrained platforms such as UAV flight controllers and portable test equipment. |
| Military Temperature Rating | Qualified from −55°C to +125°C per SN54 series standards, supporting deployment in engine bays, radar housings, and space-qualified subsystems. |
| Bus Interface Optimization | Dedicated G and A/B controls allow synchronized multiplexing of four parallel data lines - reducing control wiring and PCB trace count in backplane designs. |
Applications
| Avionics Data Bus Arbitration | Redundant Sensor Signal Routing |
|---|---|
|
Use Scenario: Selecting between primary and backup inertial measurement unit (IMU) data streams in fly-by-wire flight control computers. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer providing glitch-free, synchronized switching of four analog-to-digital converter outputs under software or watchdog control. Use Value: Eliminates need for discrete analog switches or FPGA-based routing logic, reducing BOM count and qualification effort for DO-254 compliance. |
Use Scenario: Isolating and selecting sensor inputs (temperature, pressure, vibration) during self-test or fault recovery in turbine engine controllers. IC Role / Device Role / Timing Role: Bus interface device enabling dynamic reconfiguration of sensor acquisition paths while maintaining high-impedance isolation on unused channels. Use Value: Ensures no signal leakage between redundant sensor sets, preserving measurement accuracy and meeting AS9100 traceability requirements. |
| Ruggedized Industrial PLC I/O | Military Radio Baseband Switching |
|
Use Scenario: Multiplexing digital I/O signals from multiple fieldbus modules (CAN, RS-485) onto a centralized processor bus in armored vehicle control units. IC Role / Device Role / Timing Role: High-reliability data selector handling hot-swap-capable bus segments with ESD-protected inputs and latch-up immune design. Use Value: Supports MIL-STD-1275B voltage transients and meets EN 50155 shock/vibration specs due to ceramic package mechanical stability. |
Use Scenario: Routing baseband I/Q signals between dual RF transceivers and shared ADC/DAC resources in secure HF/VHF manpack radios. IC Role / Device Role / Timing Role: Low-skew, 3-state multiplexer enabling time-division duplexing without cross-talk or signal degradation. Use Value: Delivers <10 ns channel-to-channel skew and <0.5 µA off-state leakage - critical for maintaining adjacent-channel rejection in narrowband waveforms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54HC257J | Identical electrical specs and CDIP-J packaging; differs only in TI's internal part numbering convention (SNJ prefix denotes QML-38535 Class V qualification). | Required for programs mandating full QML-38535 Class V documentation and lot traceability beyond standard SN54HC257J. | Select SNJ54HC257J when formal military certification audit trails and radiation hardness assurance are contractually required. |
| SN74HC257N | Same logic function and pinout, but rated for −40°C to +85°C in PDIP-N package; lacks military temperature range and hermetic sealing. | Suitable for commercial or industrial applications where extended temperature operation and moisture resistance are not mandated. | Choose SN74HC257N for cost-sensitive, non-military designs requiring identical functionality in standard through-hole assembly. |
Compared with SN54HC257J, SNJ54HC257J adds formal QML-38535 Class V certification overhead without altering performance, while SN74HC257N trades military-grade reliability for lower cost and broader commercial availability - making SN54HC257J the optimal balance of ruggedness, documentation, and supply continuity for defense OEMs.
Availability
SN54HC257J is available at Aetrix Electronics and suitable for avionics data bus arbitration, redundant sensor signal routing, ruggedized industrial PLC I/O, and military radio baseband switching requiring stable component supply across extended temperature and long-lifecycle programs.
Supply support for SN54HC257J 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 over 50 years of aerospace and defense component heritage.
The SN54HC257J belongs to TI's military-grade HC logic family, engineered for deterministic timing, wide-voltage interoperability, and environmental resilience in mission-critical electronic systems.
FAQ
What is the operating temperature range of the SN54HC257J?
The SN54HC257J is specified for operation from −55°C to +125°C, meeting MIL-PRF-38535 requirements for high-reliability military and aerospace applications. This extended range is enabled by its ceramic dual in-line package (CDIP-J) and process-controlled silicon, ensuring stable timing and leakage performance across extreme thermal cycling.
Does the SN54HC257J support 3.3 V logic levels?
Yes, the SN54HC257J supports 3.3 V operation fully - its 2 V to 6 V supply range, scalable VIH/VIL thresholds (e.g., VIH = 2.0 V min at VCC = 3.3 V), and 3.3 V–compatible output drive make it interoperable with modern microcontrollers and FPGAs without level-shifting circuitry.
How does the output-enable (G) pin behave during power-up?
To ensure high-impedance outputs at power-up, the G pin of the SN54HC257J must be tied to VCC through an external pullup resistor. TI specifies minimum pullup strength based on driver sink capability; a 10-kΩ resistor is commonly used to guarantee G remains high until firmware asserts control.
Is the SN54HC257J pin-compatible with the SN74HC257 series?
Yes, the SN54HC257J is pin-compatible with all SN74HC257 variants (e.g., SN74HC257N, SN74HC257D) in 16-pin packages. The same pinout applies across CDIP-J, PDIP-N, SOIC-D, and TSSOP-PW footprints - enabling drop-in replacement in existing layouts when upgrading to military temperature rating.
What is the maximum capacitive load the SN54HC257J can drive reliably?
The SN54HC257J is characterized for CL = 50 pF and CL = 150 pF loads, with propagation delay increasing predictably (e.g., tpd = 9 ns at 50 pF → 13 ns at 150 pF, VCC = 6 V). For reliable operation, total load including trace capacitance should remain ≤150 pF; layout best practices recommend short, guarded traces and local decoupling.
SN54HC257J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Circuit:
- -
- Independent Circuits:
- -
- Current - Output High, Low:
- -
- Voltage Supply Source:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN54HC257J FAQ
1.How can I place an order for SN54HC257J through Aetrix?
Please submit a Request for Quotation (RFQ) for SN54HC257J 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 SN54HC257J reliable?
The price and inventory of SN54HC257J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN54HC257J is usually 5 days.
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4.How is shipping managed for SN54HC257J?
SN54HC257J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN54HC257J 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 SN54HC257J?
For technical support, including SN54HC257J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN54HC257J requirements.
6.How does Aetrix verify that SN54HC257J is sourced from the original manufacturer or authorized distributors?
All SN54HC257J 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 SN54HC257J meets industry standards.
7.What is the process for return or replacement of SN54HC257J?
All SN54HC257J units undergo pre-shipment inspection (PSI). If there is an issue with SN54HC257J, 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 SN54HC257J part is unused and in its original packaging.
Return procedure for SN54HC257J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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