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Texas Instruments SN74ALS258AD
- Part No.:
- SN74ALS258AD
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74ALS258AD.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:9,880
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Product details
Overview
SN74ALS258AD from Texas Instruments is a 4-bit dual 2-line-to-1-line data selector/multiplexer with 3-state outputs, designed for bus-organized systems. It features A/B select control, output-enable (OE) logic, 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 interfacing in high-performance digital logic applications.
For engineers reviewing the SN74ALS258AD datasheet, SN74ALS258AD pinout, SN74ALS258AD application, or SN74ALS258AD equivalent, this page delivers verified functional identity, confirmed timing parameters (tPLH/tPHL ≤ 8 ns), absolute maximum ratings, package-specific thermal limits, and validated alternatives for legacy TTL bus interface designs.
Technical Context
The SN74ALS258AD implements two independent 2:1 multiplexers per channel, each selecting between inputs A and B under common A/B control. Each of the four Y outputs is individually 3-state enabled via shared OE, allowing bidirectional bus arbitration without external gating.
Its ALS (Advanced Low-Power Schottky) logic family delivers TTL-compatible voltage thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V), 24 mA sink capability, and propagation delays as low as 1 ns (tPHL, A/B → Y) at VCC = 5 V and TA = 25°C - optimized for synchronous data routing in 1980s–1990s industrial control and computing backplanes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL power rails and noise margin stability |
| Propagation Delay (A/B → Y) | Max 25 ns at VCC = 4.5 V, TA = 70°C - defines worst-case data path latency in synchronous bus arbitration |
| Output Drive (IOL) | 24 mA - supports fan-out to ≥10 standard TTL loads without buffering |
| 3-State Enable/Disable Time | tPZH/tPLZ ≤ 20 ns - enables rapid bus release for time-multiplexed peripheral access |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems and desktop computing environments |
| Input Voltage Thresholds | VIL ≤ 0.8 V, VIH ≥ 2 V - guarantees robust noise immunity against 0.4 V TTL-level ground bounce |
Pinout & Package
SN74ALS258AD uses a 16-pin SOIC (D) package (7.4 mm × 8.2 mm, 1.27 mm pitch), compliant with JEDEC MS-012, with gull-wing leads and 2.00 mm max height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15 | Data inputs (1A/1B, 2A/2B, 3A/3B, 4A/4B), outputs (1Y–4Y), select (A/B), enable (OE) | Direct connection to parallel data buses; A/B selects active source per channel; OE disables all Y outputs to high-impedance state |
| 3 | GND | Signal reference and power return for internal logic and output drivers |
| 16 | VCC | +5 V supply for ALS logic core and output stage; decoupling required within 10 mm |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Outputs | Enables direct connection to shared data buses without contention; OE-controlled high-impedance state isolates outputs during bus turnaround |
| Dual 2:1 Multiplexing | Four independent channels (1Y–4Y) each select between paired inputs (1A/1B, etc.), supporting parallel 4-bit data routing |
| ALS Logic Family | Combines Schottky-clamped TTL speed (≤8 ns typical tPHL) with reduced power consumption vs. standard TTL (ICC ≤ 13 mA disabled) |
| TTL-Compatible Interface | Meets standard TTL input thresholds and output drive specs - interoperable with 74LS, 74S, and earlier 74-series logic without level shifters |
Applications
| Industrial Control Backplane | Legacy Computer Memory Expansion |
|---|---|
|
Use Scenario: Routing address/data lines between multiple I/O modules and CPU on a 1980s-era PLC backplane. IC Role / Device Role / Timing Role: Data selector enabling CPU to read/write from up to four peripheral cards via shared bus segments. Use Value: Eliminates need for discrete gating logic; 24 mA sink current drives long PCB traces without signal degradation. |
Use Scenario: Selecting between main memory and expansion RAM banks in early IBM PC/AT-compatible systems. IC Role / Device Role / Timing Role: Address multiplexer controlling which 64 KB memory segment appears on the data bus during read/write cycles. Use Value: Propagation delay ≤8 ns ensures setup/hold timing compliance with 8 MHz ISA bus clock domains. |
| Test Equipment Signal Routing | Telecom Line Card Interface |
|
Use Scenario: Switching analog test signals through digital control paths in automated bench instruments. IC Role / Device Role / Timing Role: Digital-controlled analog switch driver - OE synchronizes with ADC/DAC sampling clocks to prevent bus glitches. Use Value: 3-state outputs isolate unused channels, preventing crosstalk and ensuring signal integrity during multiplexed acquisition. |
Use Scenario: Managing D-channel signaling between line interface units (LIUs) and protocol processors in T1/E1 framing hardware. IC Role / Device Role / Timing Role: Bus arbitration device selecting between maintenance, alarm, and payload data streams on shared serial control bus. Use Value: Guaranteed operation at 70°C ambient allows deployment in sealed telecom chassis without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-bit 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS257AN | Identical function and pinout; differs only in PDIP (N) package (16-pin 300-mil DIP) vs. SOIC (D) | Through-hole assembly; higher thermal resistance (1.1 W max vs. 1.3 W for D); no reflow compatibility | Select when legacy through-hole manufacturing or socket-based prototyping is required |
| SN74AS258N | Faster propagation (tPHL ≤ 4 ns), higher drive (IOL = 48 mA), but higher ICC (25.2 mA disabled) and same 0°C–70°C range | Demands tighter power delivery and heatsinking; suitable for high-speed backplanes where ALS timing is marginal | Choose for performance-critical upgrades where board layout allows increased power dissipation |
Compared with SN74ALS258AD, SN74ALS257AN offers identical logic behavior in a through-hole package for manual assembly or socketed testing, while SN74AS258N trades higher power for sub-5 ns switching - making it viable only where timing margins are insufficient with ALS-grade devices.
Availability
SN74ALS258AD is available at Aetrix Electronics and suitable for industrial control backplanes, legacy computer memory expansion, test equipment signal routing, and telecom line card interfaces requiring stable component supply across extended product lifecycles.
Supply support for SN74ALS258AD 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 U.S.-based semiconductor innovator founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74ALS258AD belongs to TI's legacy 74ALS logic family, engineered for high-speed, low-power bus interface in 1980s–1990s computing and control systems where TTL compatibility and reliability were critical.
FAQ
What is the primary function of the SN74ALS258AD?
The SN74ALS258AD is a 4-bit dual 2-line-to-1-line data selector/multiplexer with 3-state outputs. It routes one of two 4-bit input sources (A or B) to four output lines (1Y–4Y) under control of a single A/B select line and enables/disables all outputs via OE. This makes SN74ALS258AD ideal for bus arbitration and parallel data switching in TTL-based systems.
Does the SN74ALS258AD support 3.3 V operation?
No, the SN74ALS258AD is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. Operating below 4.5 V risks failure to meet VIH/VIL thresholds and may cause metastability or excessive propagation delay. For 3.3 V systems, consider modern logic families like 74LVC or 74AUP.
What is the maximum capacitive load the SN74ALS258AD can drive reliably?
The SN74ALS258AD is characterized for CL = 50 pF in switching specifications, with tPLH/tPHL guaranteed up to that load. Driving >50 pF increases propagation delay nonlinearly and may exceed timing budgets - especially at temperature extremes. For heavier loads, add series termination or buffer stages. The SN74ALS258AD datasheet does not specify drive capability beyond 50 pF.
Can the SN74ALS258AD replace the SN74LS258 in existing designs?
Yes, the SN74ALS258AD is a functional and pin-compatible upgrade to the SN74LS258, offering faster propagation (≤8 ns vs. ≤15 ns), lower power (ICC ≤13 mA disabled vs. ~18 mA), and improved noise immunity. No PCB changes are needed, but verify VCC ripple and decoupling - ALS devices exhibit sharper current transients during switching.
Is the SN74ALS258AD RoHS compliant?
Yes, the SN74ALS258AD (SOIC-D package variant) is RoHS compliant, with lead finish NIPDAU and MSL Level-1 rating. Per TI's packaging addendum, SN74ALS258AD is marked "ALS258A" and shipped in tape-and-reel (2500 pcs/reel) or tube formats. Legacy J- or FK-packaged military variants are not RoHS-compliant due to SNPB finish.
SN74ALS258AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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
SN74ALS258AD FAQ
1.How can I place an order for SN74ALS258AD through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS258AD 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 SN74ALS258AD reliable?
The price and inventory of SN74ALS258AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS258AD is usually 5 days.
3.What payment methods are accepted for SN74ALS258AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS258AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS258AD?
SN74ALS258AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS258AD 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 SN74ALS258AD?
For technical support, including SN74ALS258AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS258AD requirements.
6.How does Aetrix verify that SN74ALS258AD is sourced from the original manufacturer or authorized distributors?
All SN74ALS258AD 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 SN74ALS258AD meets industry standards.
7.What is the process for return or replacement of SN74ALS258AD?
All SN74ALS258AD units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS258AD, 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 SN74ALS258AD part is unused and in its original packaging.
Return procedure for SN74ALS258AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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