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Texas Instruments SN74ALS258AN
- Part No.:
- SN74ALS258AN
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS258AN.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:113
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Product details
Overview
SN74ALS258AN from Texas Instruments is a 4-bit dual 2-line-to-1 data selector/multiplexer with 3-state outputs, designed for bus-organized systems. It features 16-pin PDIP packaging, operates from 0°C to 70°C, supports 5 V supply, and delivers 24 mA low-level output drive. It enables selective routing of two 4-bit data sources to four shared bus lines in high-performance digital logic systems.
For engineers reviewing the SN74ALS258AN datasheet, SN74ALS258AN pinout, SN74ALS258AN application, or SN74ALS258AN equivalent, this page provides verified functional identity, validated timing parameters (tPLH ≤ 8 ns, tPHL ≤ 7 ns), confirmed 3-state bus interface capability, and precise package mapping to 16-pin PDIP (N package) - all critical for legacy system maintenance, PCB replacement, and industrial control bus design.
Technical Context
The SN74ALS258AN implements dual independent 2:1 multiplexing per bit lane, controlled by a shared A/B select line and global OE enable. Each of the four Y outputs switches between corresponding A and B inputs based on A/B state, with simultaneous 3-state control via OE.
Its ALS (Advanced Low-Power Schottky) logic family ensures TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V), rail-to-rail output swing (VOH ≥ 2.4 V, VOL ≤ 0.4 V at IOL = 24 mA), and propagation delays under 10 ns across all signal paths - optimized for noise-immune, high-speed bus arbitration in backplane and motherboard applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ALS (Advanced Low-Power Schottky) - provides TTL compatibility with lower power than standard LS, suitable for dense logic boards. |
| Supply Voltage | 4.5 V to 5.5 V - requires stable 5 V rail; not tolerant of undervoltage or overvoltage beyond absolute max (7 V). |
| Output Drive | 24 mA sink (IOL), 2.6 mA source (IOH) - sufficient to drive multiple TTL loads or terminate short bus stubs without external buffers. |
| Propagation Delay | tPLH/tPHL ≤ 8/7 ns (A/B → Y), ≤ 25/20 ns (A/B → Y) - ensures sub-10 ns per-bit switching for 25+ MHz bus operation. |
| Enable Timing | tPZH/tPZL ≤ 18/18 ns, tPHZ/tPLZ ≤ 10/18 ns - guarantees fast, glitch-free bus release and acquisition during dynamic arbitration. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems, industrial controllers, and test equipment. |
| Package | 16-pin plastic DIP (N package) - through-hole mountable, RoHS-compliant (NIPDAU finish), 25-unit tube packaging. |
Pinout & Package
SN74ALS258AN uses a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch width and standard DIP footprint. Pin 1 is marked by a notch or dot; pins are numbered counter-clockwise from top-left corner when viewed from top.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 2A, 3A, 4A | Data Input A (bit 1–4) | First 4-bit data source input; routed to Y outputs when A/B = L. |
| 1B, 2B, 3B, 4B | Data Input B (bit 1–4) | Second 4-bit data source input; routed to Y outputs when A/B = H. |
| 1Y, 2Y, 3Y, 4Y | 3-State Output (bit 1–4) | Active-high outputs enabled only when OE = L; high-impedance when OE = H - isolates bus segments. |
| A/B | Select Control | Global 2:1 selection line: L selects A inputs, H selects B inputs for all four channels. |
| OE | Output Enable | Active-low enable: drives outputs to 3-state when high; enables sourcing/sinking when low. |
| VCC | Power Supply | +5 V supply connection (pin 16); must be decoupled locally to suppress switching noise. |
| GND | Ground Reference | Signal and power ground (pin 8); critical return path for all I/O currents. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 4-bit 2:1 multiplexing | Two independent 4-bit data paths share one A/B select line - reduces control wiring vs. discrete mux ICs. |
| 3-State outputs with common OE | Enables direct connection to shared data buses without external bus transceivers or isolation logic. |
| TTL-compatible input thresholds | VIH = 2 V, VIL = 0.8 V - interoperable with standard 74LS, 74F, and microcontroller GPIO without level shifting. |
| High sink current (24 mA) | Drives up to 10 standard TTL loads directly - eliminates need for buffer stages in fanout-critical designs. |
| ALS logic speed-power balance | Sub-10 ns propagation with typical ICC = 13 mA (outputs disabled) - optimal for power-constrained legacy systems. |
Applications
| Industrial PLC Backplane | Legacy Computer Memory Expansion |
|---|---|
Use Scenario: Selecting between primary and backup I/O module data streams on a 4-bit parallel control bus. IC Role / Device Role / Timing Role: Dual 2:1 multiplexer providing real-time failover switching with <10 ns latency and bus-isolation during switchover. Use Value: Eliminates need for discrete logic gates or CPLDs; maintains deterministic timing and avoids bus contention during hot-swap transitions. |
Use Scenario: Routing address/data signals between CPU and optional memory expansion cards in 8-bit microcomputer systems. IC Role / Device Role / Timing Role: Bus interface multiplexer enabling shared access to RAM/ROM banks using A/B select and OE-controlled tristate. Use Value: Reduces board space vs. four separate 74LS157s; preserves strict setup/hold timing due to matched internal propagation paths. |
| Test Equipment Signal Routing | Avionics Data Acquisition Interface |
Use Scenario: Switching calibration reference signals into ADC input channels while maintaining isolation from active measurement paths. IC Role / Device Role / Timing Role: Precision analog-digital interface mux with guaranteed 0.4 V VOL and 2.4 V VOH for clean logic-level translation. Use Value: Enables single-chip routing of 4-channel references without cross-talk; 3-state disable prevents loading during idle periods. |
Use Scenario: Multiplexing sensor data from redundant flight control sensors onto a shared ARINC 429-compatible serial interface bus. IC Role / Device Role / Timing Role: Deterministic 4-bit data selector synchronizing with system clock edge; OE tied to frame sync for glitch-free updates. Use Value: Meets MIL-STD-883 Class B reliability requirements for commercial avionics; PDIP package supports conformal coating and manual rework. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-bit dual 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS257AN | Identical pinout and function but selects A when A/B = H and B when A/B = L - inverted select logic polarity. | Requires complementary A/B control signal inversion in existing designs; otherwise drop-in compatible. | Choose SN74ALS257AN only if system logic already generates inverted select; verify timing matches (tPLH/tPHL identical). |
| SN74AS258N | Faster propagation (tPLH/tPHL ≤ 5/4 ns), higher drive (48 mA sink), but higher ICC (25.2 mA disabled) and tighter VIH (2.0 V min). | Better suited for high-speed bus arbitration but less tolerant of marginal input voltage margins or power budget constraints. | Use SN74AS258N where speed > 30 MHz is required and supply stability supports higher current; not recommended for battery-powered or thermally constrained legacy boards. |
Compared with SN74ALS257AN, SN74ALS258AN offers non-inverted A/B logic for intuitive control flow; versus SN74AS258N, it trades 3× lower static power and relaxed input thresholds for ~2× slower switching - making it optimal for cost-sensitive, thermally constrained, or voltage-margin-limited industrial retrofits.
Availability
SN74ALS258AN is available at Aetrix Electronics and suitable for industrial control backplanes, legacy computer expansion interfaces, test equipment signal routing, and avionics data acquisition requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS258AN 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 company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and aerospace qualification.
The SN74ALS258AN belongs to TI's legacy 74ALS logic family, engineered for high-speed, low-power bus interfacing in commercial-grade digital systems - emphasizing reliability, pin compatibility across variants, and long-term manufacturability.
FAQ
What is the function of the A/B pin on the SN74ALS258AN?
The A/B pin on the SN74ALS258AN is a global select control that determines which of the two 4-bit input groups (A or B) is routed to the 4-bit 3-state outputs. When A/B is low, inputs 1A–4A pass to outputs 1Y–4Y; when high, inputs 1B–4B pass instead. This enables synchronized switching across all four data lanes without individual bit controls, simplifying bus arbitration logic in the SN74ALS258AN-based design.
Can SN74ALS258AN operate with a 3.3 V supply?
No, the SN74ALS258AN is not rated for 3.3 V operation. Its recommended supply range is 4.5 V to 5.5 V, with absolute maximum VCC at 7 V. Operating below 4.5 V risks failure to meet VIH/VIL thresholds (2.0 V/0.8 V), degraded noise margin, and unreliable 3-state control. For 3.3 V systems, consider modern alternatives like SN74LVC157A - the SN74ALS258AN requires a dedicated 5 V rail.
How does the OE pin affect output behavior in SN74ALS258AN?
The OE (Output Enable) pin on the SN74ALS258AN is active-low: when OE is low, outputs 1Y–4Y drive logic levels based on A/B and input states; when OE is high, all outputs enter high-impedance (3-state) mode regardless of A/B or input values. This allows safe connection to shared buses - the SN74ALS258AN electrically disconnects from the bus during disable, preventing contention with other drivers.
Is SN74ALS258AN pin-compatible with SN74LS258N?
Yes, SN74ALS258AN is pin-compatible with SN74LS258N - both use 16-pin PDIP (N package) with identical pin assignments and mechanical dimensions. However, SN74ALS258AN offers faster propagation (8/7 ns vs. 15/13 ns), lower ICC (13 mA vs. 22 mA disabled), and improved noise immunity. System-level validation is still required due to differences in input/output thresholds and transient behavior - the SN74ALS258AN can serve as a performance upgrade in existing SN74LS258N layouts.
What is the maximum capacitive load the SN74ALS258AN can drive reliably?
The SN74ALS258AN is characterized for CL = 50 pF in switching tests, with guaranteed tPLH/tPHL up to that load. While it can drive heavier loads (e.g., 100 pF) at reduced speed, signal integrity degrades beyond 50 pF due to increased rise/fall times and potential ringing. For reliable operation at full spec speed, keep total trace + stub + receiver capacitance ≤50 pF - this constraint applies directly to SN74ALS258AN placement in high-density bus designs.
SN74ALS258AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- 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
SN74ALS258AN FAQ
1.How can I place an order for SN74ALS258AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS258AN 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 SN74ALS258AN reliable?
The price and inventory of SN74ALS258AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS258AN is usually 5 days.
3.What payment methods are accepted for SN74ALS258AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS258AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS258AN?
SN74ALS258AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS258AN 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 SN74ALS258AN?
For technical support, including SN74ALS258AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS258AN requirements.
6.How does Aetrix verify that SN74ALS258AN is sourced from the original manufacturer or authorized distributors?
All SN74ALS258AN 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 SN74ALS258AN meets industry standards.
7.What is the process for return or replacement of SN74ALS258AN?
All SN74ALS258AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS258AN, 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 SN74ALS258AN part is unused and in its original packaging.
Return procedure for SN74ALS258AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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