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Texas Instruments SN74HCT257DRE4
- Part No.:
- SN74HCT257DRE4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HCT257DRE4.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,907
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Product details
Overview
SN74HCT257DRE4 from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state outputs, designed for bus-organized digital systems. It operates at 4.5 V–5.5 V, delivers ±6 mA output drive at 5 V, exhibits typical propagation delay of 17 ns at 5.5 V, and supports TTL-voltage-compatible inputs for seamless integration with legacy logic. It enables dynamic routing of four independent 2-input data channels onto shared bus lines in industrial control and instrumentation interfaces.
For engineers reviewing the SN74HCT257DRE4 datasheet, SN74HCT257DRE4 pinout, SN74HCT257DRE4 application, or SN74HCT257DRE4 equivalent, key selection criteria include its 3-state bus interface capability, guaranteed high-impedance output disable timing (tdis = 34 ns max at 5.5 V), input leakage ≤1 µA, and SOIC-16 package compatibility with standard PCB layouts for signal routing and bus arbitration functions.
Technical Context
The SN74HCT257DRE4 implements four independent 2:1 multiplexers sharing a common active-low output-enable (OE) control, allowing simultaneous 3-state gating of all four Y outputs. Each channel selects between A and B inputs based on the address select (A/B) line, with buffered inputs and outputs ensuring signal integrity across noisy industrial buses.
Its HCT logic family ensures CMOS-level power efficiency while maintaining TTL input thresholds (VIH = 2 V min, VIL = 0.8 V max), enabling direct interfacing with 5 V TTL sources without level shifters. The device's 13 pF typical power-dissipation capacitance and 80 µA max ICC support low-static-power operation in battery-backed or thermally constrained embedded systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation across industrial 5 V rail tolerances without external regulation. |
| Propagation Delay (tpd) | 17 ns typical at 5.5 V, CL = 50 pF - Enables reliable 25 MHz+ data switching in synchronous bus applications. |
| Output Drive | ±6 mA at 5 V - Sufficient to drive 10 LSTTL loads or terminate short PCB traces without buffering. |
| Input Leakage Current | ≤1 µA max - Prevents unintended logic state shifts when inputs are pulled via high-value resistors. |
| 3-State Enable Timing (tdis) | 34 ns max at 5.5 V - Guarantees clean bus release before next data cycle, critical for multi-master arbitration. |
| Input Compatibility | TTL-voltage compatible (VIH ≥ 2 V, VIL ≤ 0.8 V) - Directly interfaces with legacy 5 V TTL, microcontroller GPIO, and FPGA I/O banks. |
| Power Consumption | 80 µA max ICC - Supports low-quiescent-current designs where standby power budget is <100 µW per channel. |
Pinout & Package
SN74HCT257DRE4 is packaged in a 16-pin SOIC (D package), measuring 9.90 mm × 3.90 mm, with standard 1.27 mm pitch and gull-wing leads suitable for reflow soldering and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | A/B | Global address select controlling A vs. B input choice for all four channels. |
| 2–4, 5–7, 10–11, 13–14 | 1A/1B, 2A/2B, 3A/3B, 4A/4B | Eight dedicated data inputs - two per channel, supporting independent 2:1 selection per 4-bit lane. |
| 4, 7, 9, 12 | 1Y, 2Y, 3Y, 4Y | Four 3-state outputs - simultaneously enabled/disabled by OE; high-impedance when OE = high. |
| 8 | GND | Ground reference for logic and power return; must be low-inductance connection to minimize noise coupling. |
| 15 | G (OE) | Active-low output enable - asserts 3-state mode when high; tied to VCC via pullup for power-up safety. |
| 16 | VCC | Positive supply (4.5–5.5 V); requires local 0.1 µF bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| High-current 3-state outputs | ±6 mA drive capability enables direct connection to system data buses without external drivers or buffers. |
| Buffered inputs and outputs | Reduces capacitive loading effects and improves noise immunity in multi-drop bus configurations. |
| TTL-voltage-compatible inputs | Eliminates need for level-shifting circuitry when interfacing with legacy 5 V TTL or microcontroller GPIOs. |
| Low input current (≤1 µA) | Permits use of high-value pull-up/down resistors (e.g., 100 kΩ) without compromising logic thresholds. |
| Controlled power-up behavior | OE tied to VCC via pullup ensures outputs remain in high-impedance state during power ramp, preventing bus contention. |
Applications
| Industrial PLC I/O Expansion | Legacy System Bus Arbitration |
|---|---|
Use Scenario: Adding modular analog/digital I/O modules to programmable logic controllers using shared backplane data lanes. IC Role / Device Role / Timing Role: Multiplexes sensor/actuator data from multiple I/O cards onto a single 4-bit data bus under CPU address control. Use Value: Reduces backplane pin count by 50% versus discrete wiring, while maintaining deterministic 17 ns channel switching for real-time scan cycles. |
Use Scenario: Enabling multiple microcontrollers or peripherals to share a common 4-bit status/data bus in retro-computing or test equipment. IC Role / Device Role / Timing Role: Acts as bidirectional bus switch controlled by master arbitration logic, isolating inactive devices via 3-state outputs. Use Value: Prevents bus contention during handoff transitions with guaranteed tdis ≤34 ns, ensuring glitch-free data handover. |
| Embedded Instrumentation Signal Routing | Test Fixture Channel Selection |
Use Scenario: Selecting between calibration reference signals and sensor inputs in portable multimeters or data loggers. IC Role / Device Role / Timing Role: Routes dual-sourced analog front-end signals (e.g., voltage/current ranges) to ADC input under firmware control. Use Value: Provides TTL-compatible control interface with <1 µA input leakage, preserving accuracy of high-impedance measurement paths. |
Use Scenario: Automating stimulus/sense path configuration across multiple DUTs in production test fixtures with fixed-pin-count handlers. IC Role / Device Role / Timing Role: Switches 4-channel test signals (clock, trigger, data, strobe) between tester resources and DUT pins. Use Value: Delivers 17 ns propagation delay and ±6 mA drive to maintain signal edge fidelity across 15 cm fixture traces at 10 MHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT157DR | Identical logic function and pinout; differs only in output-enable polarity (active-high vs. SN74HCT257DRE4's active-low OE). | Requires inverted OE control signal; unsuitable where existing firmware assumes active-low gating. | Select SN74HCT157DR only if board layout allows OE signal inversion or if new design permits firmware adaptation. |
| 74ACT257M | Faster tpd (10 ns typ), higher drive (±24 mA), but requires 4.5–5.5 V supply and has higher ICC (2 mA max). | Better suited for high-speed bus applications (>40 MHz), but increases power and thermal load in space-constrained modules. | Choose 74ACT257M when speed outweighs quiescent power constraints; otherwise SN74HCT257DRE4 offers optimal balance for industrial bus interfaces. |
Compared with SN74HCT157DR, SN74HCT257DRE4 provides native active-low OE for direct compatibility with standard bus arbitration logic; compared with 74ACT257M, it reduces standby power by >20× while retaining sufficient speed for 25 MHz bus operation - making it ideal for cost-sensitive, thermally constrained industrial control nodes.
Availability
SN74HCT257DRE4 is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy bus arbitration systems, and embedded instrumentation requiring stable component supply with long-term lifecycle assurance.
Supply support for SN74HCT257DRE4 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 solutions, with over 50 years of innovation in industrial and automotive electronics.
The SN74HCT257DRE4 belongs to TI's HCT logic family, engineered for 5 V mixed-signal systems requiring TTL compatibility, low power, and robust bus interface capability in harsh industrial environments.
FAQ
What is the operating voltage range for SN74HCT257DRE4?
The SN74HCT257DRE4 operates within a supply voltage range of 4.5 V to 5.5 V. This range ensures compatibility with standard 5 V industrial power rails while accommodating typical ±5% tolerance. Operation outside this range may cause functional failure or permanent damage, as specified in the absolute maximum ratings table of the official datasheet.
Does SN74HCT257DRE4 support TTL-level inputs?
Yes, SN74HCT257DRE4 features TTL-voltage-compatible inputs with VIH ≥ 2.0 V and VIL ≤ 0.8 V at VCC = 4.5 V to 5.5 V. This allows direct connection to legacy 5 V TTL outputs, microcontroller GPIOs, and FPGA I/O banks without level-shifting circuitry - a core design advantage of the HCT logic family.
What is the maximum output drive capability of SN74HCT257DRE4?
SN74HCT257DRE4 delivers ±6 mA output drive at 5 V, sufficient to drive up to 10 LSTTL loads or terminate short PCB traces. This specification is verified under recommended operating conditions and ensures reliable signal integrity in bus-organized systems without external buffer stages.
How does the 3-state output control work on SN74HCT257DRE4?
SN74HCT257DRE4 uses an active-low output-enable (OE) input (pin 15). When OE is low, all four Y outputs actively drive logic levels selected by the A/B input; when OE is high, all Y outputs enter high-impedance state. To prevent bus contention at power-up, TI recommends tying OE to VCC via a pullup resistor.
What package type is used for SN74HCT257DRE4?
SN74HCT257DRE4 is supplied in a 16-pin SOIC (D package) with body dimensions of 9.90 mm × 3.90 mm and 1.27 mm lead pitch. This surface-mount package supports automated assembly, reflow soldering, and is footprint-compatible with other TI SOIC-16 logic devices for design reuse.
SN74HCT257DRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 6mA, 6mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HCT257DRE4 FAQ
1.How can I place an order for SN74HCT257DRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT257DRE4 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 SN74HCT257DRE4 reliable?
The price and inventory of SN74HCT257DRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT257DRE4 is usually 5 days.
3.What payment methods are accepted for SN74HCT257DRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT257DRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT257DRE4?
SN74HCT257DRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT257DRE4 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 SN74HCT257DRE4?
For technical support, including SN74HCT257DRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT257DRE4 requirements.
6.How does Aetrix verify that SN74HCT257DRE4 is sourced from the original manufacturer or authorized distributors?
All SN74HCT257DRE4 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 SN74HCT257DRE4 meets industry standards.
7.What is the process for return or replacement of SN74HCT257DRE4?
All SN74HCT257DRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT257DRE4, 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 SN74HCT257DRE4 part is unused and in its original packaging.
Return procedure for SN74HCT257DRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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