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Texas Instruments SN74ALS257ANG4
- Part No.:
- SN74ALS257ANG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS257ANG4.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,332
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Product details
Overview
SN74ALS257ANG4 from Texas Instruments is a quad 2-input data selector/multiplexer with 3-state outputs, designed for bus-organized systems requiring signal routing from four 4-bit sources to four output lines. It operates at 4.5–5.5 V, delivers 24 mA sink current, supports 0°C to 70°C ambient, and interfaces directly with system buses via high-impedance outputs when OE is high.
For engineers reviewing the SN74ALS257ANG4 datasheet, SN74ALS257ANG4 pinout, SN74ALS257ANG4 application, or SN74ALS257ANG4 equivalent, this device serves as a legacy-compatible bus multiplexer in industrial control backplanes, legacy instrumentation data paths, and TTL-level logic subsystems where low propagation delay (≤10 ns) and robust 3-state bus driving are required.
Technical Context
The SN74ALS257ANG4 implements four independent 2:1 multiplexers sharing a common A/B select line and output-enable (OE) control. Each Y output reflects either the corresponding A or B input based on the logic level of A/B, while OE asserts high-impedance state across all outputs simultaneously.
It uses Advanced Low-Power Schottky (ALS) bipolar technology, delivering faster switching than standard LS logic (tPHL/tPLH ≤12 ns), higher drive strength (IOL = 24 mA), and lower ICC in disabled state (9–14 mA) compared to 74LS257. Its 16-pin PDIP (N) package matches industry-standard footprint compatibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures reliable operation across standard 5 V ±10% rail tolerances in legacy TTL systems. |
| Output Drive (IOL) | 24 mA - Sinks sufficient current to drive multiple TTL inputs or small capacitive loads without external buffering. |
| Propagation Delay (tPHL) | ≤12 ns - Enables use in high-speed data path selection up to ~40 MHz clock-equivalent timing in synchronous bus architectures. |
| 3-State Enable Time (tPZH) | ≤16 ns - Guarantees fast bus release during output disable, minimizing contention windows in shared-data-bus applications. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial-grade embedded systems including test equipment, PLC I/O modules, and industrial controllers. |
| Input Logic Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - Compatible with standard TTL and ALS-family logic levels, ensuring noise-immune interfacing. |
Pinout & Package
SN74ALS257ANG4 is supplied in a 16-pin plastic dual in-line package (PDIP-N), 300-mil width, with standard through-hole mounting and 0.1-inch pin pitch. Pin 1 is marked by a notch or dot at the top-left corner of the package body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 2A, 3A, 4A | Data Input A | First input pair per multiplexer channel; selected when A/B = L. |
| 1B, 2B, 3B, 4B | Data Input B | Second input pair per channel; selected when A/B = H. |
| 1Y, 2Y, 3Y, 4Y | 3-State Output | Active-high multiplexed output; high-impedance when OE = H. |
| A/B | Select Control | Global 2:1 select line determining whether A or B inputs appear at outputs. |
| OE | Output Enable | Active-low enable; drives all Y outputs into high-Z state when high. |
| VCC | Power Supply | +5 V supply connection (Pin 16); decoupling recommended near pin. |
| GND | Ground Reference | Signal and power ground return (Pin 8); critical for noise immunity and switching stability. |
Key Features
| Feature | Design Value |
|---|---|
| Quad 2:1 Multiplexer Function | Routes four independent 2-input data streams synchronously using one shared select line-ideal for parallel bus arbitration. |
| 3-State Outputs with Common OE | Enables direct connection to shared data buses without external bus transceivers; eliminates contention during disable. |
| ALS Technology Performance | Delivers 2× speed and 50% lower power vs. 74LS257, enabling denser logic designs in space-constrained legacy systems. |
| TTL-Compatible Input/Output Levels | Guaranteed VIH/VIL margins ensure interoperability with 74xx, 74LSxx, and other TTL families without level-shifting circuitry. |
| PDIP-16 Footprint Compatibility | Mechanically and electrically compatible with industry-standard 16-pin DIP sockets and PCB layouts used across decades of hardware. |
Applications
| Industrial Backplane Multiplexing | Legacy Instrumentation Data Routing |
|---|---|
|
Use Scenario: Selecting between primary and backup sensor data streams in programmable logic controller (PLC) I/O modules. IC Role / Device Role / Timing Role: Quad 2:1 data selector routing analog-to-digital converter outputs onto a shared 4-bit data bus under microcontroller control. Use Value: Eliminates need for discrete logic gates or additional bus buffers, reducing component count and board area in cost-sensitive industrial hardware. |
Use Scenario: Switching between calibration and measurement modes in benchtop multimeters and oscilloscope front-end signal paths. IC Role / Device Role / Timing Role: Bus interface multiplexer isolating ADC reference channels from active measurement channels during auto-calibration sequences. Use Value: Provides deterministic, glitch-free channel selection with sub-15 ns enable/disable timing-critical for maintaining measurement accuracy. |
| Embedded System Address/Data Bus Expansion | TTL-Level Logic Subsystem Interfacing |
|
Use Scenario: Expanding address decoding capability in 8-bit microprocessor-based systems (e.g., Z80, 8085) with limited native address lines. IC Role / Device Role / Timing Role: Multiplexing upper/lower nibbles of address bus to support memory-mapped peripheral selection in constrained pin-count designs. Use Value: Enables reuse of existing bus traces and simplifies PCB layout versus adding full-width address latches or CPLDs. |
Use Scenario: Interfacing disparate TTL logic families (e.g., 74ALS, 74AS, 74F) within a single control board where voltage and drive mismatch exists. IC Role / Device Role / Timing Role: Level- and drive-capability translator providing buffered, 3-state-isolated signal paths between incompatible logic subcircuits. Use Value: Prevents loading effects and timing skew while preserving signal integrity across mixed-technology subsystem boundaries. |
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 |
|---|---|---|---|
| SN74ALS257AN | Same ALS family, identical electrical specs and pinout; G4 suffix denotes tape-and-reel packaging variant (not functional difference). | No functional difference-identical use cases and drop-in replacement in all PDIP-16 layouts. | Select SN74ALS257AN for tube-packaged units; SN74ALS257ANG4 is functionally identical but supplied in tape-and-reel for automated assembly. |
| SN74AS257N | Faster propagation (≤6 ns vs. ≤12 ns), higher drive (48 mA vs. 24 mA), but increased ICC (19.7 mA vs. 14 mA) and tighter VIH (2.0 V min vs. same). | Better suited for ultra-high-speed bus switching where timing margin is critical; less suitable for low-power or thermally constrained designs. | Choose SN74AS257N only when sub-10 ns timing is mandatory and power/thermal budget allows; otherwise SN74ALS257ANG4 offers optimal balance. |
Compared with SN74ALS257AN, SN74ALS257ANG4 provides identical functionality in tape-and-reel format for SMT production, while SN74AS257N trades higher speed and drive for greater power consumption-making it appropriate only when ALS timing limits are insufficient for the target system clock domain.
Availability
SN74ALS257ANG4 is available at Aetrix Electronics and suitable for industrial control backplanes, legacy instrumentation data paths, and TTL-level logic subsystems requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS257ANG4 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with deep heritage in TTL and advanced bipolar technologies.
The SN74ALS257ANG4 belongs to TI's legacy 74ALS logic family, engineered for high-speed, low-power bus interfacing in industrial, test, and computing systems where reliability and pin compatibility across generations are essential.
FAQ
What is the operating temperature range for SN74ALS257ANG4?
The SN74ALS257ANG4 is rated for commercial operation from 0°C to 70°C. This range aligns with standard industrial ambient conditions and ensures stable performance in non-military, non-automotive embedded systems such as programmable logic controllers and test equipment where extended thermal cycling is not required. The device does not support extended or military temperature grades.
Is SN74ALS257ANG4 pin-compatible with SN74LS257?
Yes, SN74ALS257ANG4 is pin-compatible with SN74LS257 and shares identical 16-pin PDIP layout, pin functions, and basic logic behavior. However, SN74ALS257ANG4 offers improved speed (≤12 ns vs. ≤25 ns), higher output drive (24 mA vs. 8 mA), and lower quiescent current-making it a direct performance upgrade without PCB changes.
What does the "G4" suffix indicate in SN74ALS257ANG4?
The "G4" suffix in SN74ALS257ANG4 denotes Texas Instruments' tape-and-reel packaging variant for surface-mount assembly. It specifies carrier tape format, reel size (330 mm diameter), and orientation (Q1 quadrant). Electrically and functionally, SN74ALS257ANG4 is identical to SN74ALS257AN-the "G4" reflects packaging only, not a different silicon revision or specification.
Can SN74ALS257ANG4 drive multiple TTL inputs directly?
Yes, SN74ALS257ANG4 can drive up to 20 standard TTL inputs (based on its 24 mA sink capability and 0.4 V VOL spec at IOL = 24 mA). Its output structure meets or exceeds the fan-out requirements of legacy 74xx-series TTL loads, eliminating the need for external buffer stages in most bus-interface applications.
Does SN74ALS257ANG4 require external pull-up resistors on its outputs?
No, SN74ALS257ANG4 does not require external pull-up resistors on its outputs. Its 3-state outputs are actively driven high or low when enabled, and present high impedance (IOZL/IOZH ≤ ±20 µA) when disabled. Pull-ups are unnecessary unless interfacing with open-collector systems-a configuration outside the device's intended use case.
SN74ALS257ANG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74ALS257ANG4 FAQ
1.How can I place an order for SN74ALS257ANG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS257ANG4 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 SN74ALS257ANG4 reliable?
The price and inventory of SN74ALS257ANG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS257ANG4 is usually 5 days.
3.What payment methods are accepted for SN74ALS257ANG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS257ANG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS257ANG4?
SN74ALS257ANG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS257ANG4 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 SN74ALS257ANG4?
For technical support, including SN74ALS257ANG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS257ANG4 requirements.
6.How does Aetrix verify that SN74ALS257ANG4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS257ANG4 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 SN74ALS257ANG4 meets industry standards.
7.What is the process for return or replacement of SN74ALS257ANG4?
All SN74ALS257ANG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS257ANG4, 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 SN74ALS257ANG4 part is unused and in its original packaging.
Return procedure for SN74ALS257ANG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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