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Texas Instruments SN74AS258D
- Part No.:
- SN74AS258D
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS258D.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,932
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Product details
Overview
SN74AS258D from Texas Instruments is a 4-bit dual 2-line-to-1-line data selector/multiplexer with 3-state outputs, designed for bus interface in high-performance TTL systems. It features A/B select control, output-enable (OE) input, and operates across 0°C to 70°C with VCC = 4.5–5.5 V. Its 16-pin SOIC (D) package supports direct system-bus connection in industrial control and legacy computing backplanes.
For engineers reviewing the SN74AS258D datasheet, SN74AS258D pinout, SN74AS258D application, or SN74AS258D equivalent, key selection criteria include propagation delay (tPHL/tPLH ≤ 6 ns), 3-state output drive capability (IOL = 48 mA), and compatibility with 5-V TTL logic families in space-constrained PCB layouts.
Technical Context
The SN74AS258D implements two independent 2:1 multiplexers per device, each selecting between two 4-bit inputs (A or B) based on the A/B control line. All eight outputs (1Y–4Y) share a common 3-state enable (OE), allowing simultaneous bus isolation.
It belongs to the 74AS logic family, delivering faster switching than ALS variants (e.g., tPHL = 1–4 ns vs. 2–7 ns for SN74ALS258A) and higher output drive (48 mA sink vs. 24 mA), while maintaining TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation under standard 5-V TTL supply tolerances. |
| tPHL / tPLH (A/B → Y) | 2 ns (min) / 9.5 ns (max) - Enables sub-10 ns signal routing critical for high-speed bus arbitration. |
| IOL (Output Sink) | 48 mA - Drives heavy capacitive loads or multiple TTL inputs without external buffers. |
| IOH (Output Source) | −15 mA - Supports active pull-up in mixed-signal bus environments with open-collector interfaces. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial-grade embedded systems and industrial control panels. |
| 3-State Enable Delay | tPZH ≤ 8 ns, tPLZ ≤ 6.5 ns - Guarantees fast bus release during dynamic multiplexing sequences. |
Pinout & Package
SN74AS258D uses a 16-pin SOIC (D) package with 1.27 mm pitch, 7.5 mm width, and 2.00 mm max height - optimized for automated SMT assembly and thermal dissipation in dense logic arrays.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A/B) | Select control input | Determines whether A-inputs (A=LOW) or B-inputs (A=HIGH) are routed to outputs. |
| 2–5, 10–13 (1A–4A, 1B–4B) | Data inputs | Two independent 4-bit input buses; each pair feeds one multiplexer stage. |
| 6–9, 14–15 (1Y–4Y) | 3-state outputs | Active-high outputs disabled when OE is HIGH; compatible with shared data buses. |
| 16 (VCC) | Power supply | +5 V supply rail; decoupling required within 10 mm of pin for noise immunity. |
| 8 (GND) | Ground reference | Common return path for all logic and output currents; must be low-impedance. |
| 9 (OE) | Output-enable input | Active-LOW control: drives all Y outputs into high-impedance state when HIGH. |
Key Features
| Feature | Design Value |
|---|---|
| High-speed AS-family logic | Delivers 2× faster propagation than ALS equivalents, reducing bus contention latency in real-time control loops. |
| 48-mA output sink capability | Eliminates need for external bus drivers when interfacing with multiple TTL loads or long trace runs. |
| Common 3-state output control | Single OE pin synchronizes disable/enable of all eight outputs - essential for glitch-free bus handoff. |
| TTL-compatible input thresholds | VIL ≤ 0.8 V and VIH ≥ 2 V ensure robust noise margin against crosstalk in mixed-voltage systems. |
| SOIC (D) packaging | 16-pin surface-mount footprint reduces PCB area by >50% vs. DIP, supporting high-density logic consolidation. |
Applications
| Industrial PLC Backplane | Legacy Computer Bus Arbitration |
|---|---|
|
Use Scenario: Selecting between redundant sensor data streams or I/O module addresses on a 16-bit parallel backplane. IC Role / Device Role: Dual 2:1 multiplexer enabling dynamic reconfiguration of address/data paths without FPGA intervention. Use Value: Sub-10 ns switching ensures deterministic timing in scan-cycle-critical motion control systems. |
Use Scenario: Resolving bus mastership conflicts between CPU, DMA controller, and video coprocessor in 1980s-era microcomputers. IC Role / Device Role: Bus interface multiplexer isolating competing peripherals using shared 8-bit data lines. Use Value: 48-mA sink current drives legacy TTL bus capacitance directly, avoiding level-shifter overhead. |
| Test Equipment Signal Routing | Avionics Data Acquisition Interface |
|
Use Scenario: Switching calibration reference signals into ADC front-ends during automated functional test sequences. IC Role / Device Role: Precision analog-path selector with digital-controlled 3-state outputs preventing signal leakage. Use Value: Low tPLZ/tPZL (≤6.5 ns) enables synchronized channel switching at >10 MHz test clock rates. |
Use Scenario: Multiplexing discrete sensor outputs (temperature, pressure, voltage) onto a centralized ARINC 429 bus controller. IC Role / Device Role: Robust 5-V tolerant interface IC handling EMI-prone avionics wiring harnesses. Use Value: Guaranteed 0°C–70°C operation meets DO-160 environmental requirements for non-flight-critical subsystems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar data selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS258AN | ALS-family variant: slower (tPHL ≤ 7 ns), lower drive (IOL = 24 mA), same pinout and function. | Suitable for cost-sensitive, lower-speed industrial boards where <10 MHz bus timing is acceptable. | Choose SN74ALS258AN if power consumption (ICC = 15.5 mA) and board-level noise immunity outweigh speed needs. |
| SN74AS257D | Same AS family, but dual 4:1 configuration (single A/B select per 4-bit group); identical timing and drive specs. | Better suited for applications requiring independent selection of two 4-bit channels rather than paired 2:1 paths. | Select SN74AS257D when channel independence is required - e.g., separate data and address bus routing. |
Compared with SN74ALS258AN and SN74AS257D, the SN74AS258D provides optimal balance of speed, drive strength, and dual 2:1 topology for time-critical bus arbitration - making it preferred for legacy-compatibility designs demanding sub-10 ns response.
Availability
SN74AS258D is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy computer bus arbitration, test equipment signal routing, and avionics data acquisition interfaces requiring stable component supply and long-term obsolescence management.
Supply support for SN74AS258D 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 for industrial, automotive, and communications markets.
The SN74AS258D belongs to TI's 74AS advanced Schottky TTL logic family, engineered for high-speed, low-noise digital interface applications in mission-critical legacy and upgrade systems.
FAQ
What logic family does SN74AS258D belong to, and how does it differ from 74LS or 74ALS variants?
SN74AS258D belongs to the 74AS (Advanced Schottky) TTL family. It delivers significantly faster propagation delays (e.g., tPHL ≤ 4 ns) and higher output drive (48 mA sink) than 74ALS (tPHL ≤ 7 ns, 24 mA) or 74LS (tPHL ≤ 15 ns, 8 mA). Unlike LS, AS maintains full TTL input compatibility while achieving near-AC performance - making SN74AS258D ideal for upgrading legacy systems without redesigning interface logic.
Can SN74AS258D operate with a 3.3-V supply?
No, SN74AS258D is specified only for VCC = 4.5 V to 5.5 V. Its internal Schottky-clamped transistor structure requires ≥4.5 V to guarantee correct logic thresholds and output voltage levels (VOH ≥ 2.4 V, VOL ≤ 0.5 V). Using 3.3 V risks undefined operation, excessive ICC, or failure to meet timing specs - always use a dedicated 5-V rail or level-shifting interface when connecting to 3.3-V systems.
How does the A/B pin control signal routing in SN74AS258D?
The A/B pin is a global select input: when LOW, all four Y outputs (1Y–4Y) reflect the corresponding A-inputs (1A–4A); when HIGH, they reflect the B-inputs (1B–4B). This synchronous 2:1 selection applies identically across all four bit lanes - enabling atomic switching of parallel data paths. The SN74AS258D does not support independent per-bit selection; for that, SN74AS257D (dual 4:1) would be required.
Is SN74AS258D pin-compatible with SN74ALS258A or SN74LS258N?
Yes - SN74AS258D shares identical pinout, function table, and DC electrical behavior with SN74ALS258A and SN74LS258N in 16-pin packages (D, N, J). All three use the same terminal mapping: pins 1 (A/B), 2–5/10–13 (inputs), 6–9/14–15 (outputs), 8 (GND), 9 (OE), and 16 (VCC). However, SN74AS258D's superior speed and drive require verifying layout parasitics and decoupling to avoid ringing or ground bounce.
What is the maximum capacitive load SN74AS258D can drive while maintaining guaranteed timing?
SN74AS258D's switching characteristics (tPHL, tPLH) are characterized at CL = 50 pF with R1 = R2 = 500 Ω. While it can drive heavier loads due to its 48-mA sink capability, exceeding 50 pF increases propagation delay nonlinearly and may degrade edge rate. For >50 pF traces or fanout >10 TTL loads, add series termination or buffer stages - the SN74AS258D itself is not rated for >50 pF in datasheet timing guarantees.
SN74AS258D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74AS258D FAQ
1.How can I place an order for SN74AS258D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS258D 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 SN74AS258D reliable?
The price and inventory of SN74AS258D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS258D is usually 5 days.
3.What payment methods are accepted for SN74AS258D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS258D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS258D?
SN74AS258D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS258D 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 SN74AS258D?
For technical support, including SN74AS258D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS258D requirements.
6.How does Aetrix verify that SN74AS258D is sourced from the original manufacturer or authorized distributors?
All SN74AS258D 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 SN74AS258D meets industry standards.
7.What is the process for return or replacement of SN74AS258D?
All SN74AS258D units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS258D, 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 SN74AS258D part is unused and in its original packaging.
Return procedure for SN74AS258D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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