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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

Texas Instruments SN74AS258N

Name: SN74AS258N
Brand: Texas Instruments
SKU: SN74AS258N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74AS258N

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 16-DIP (0.300", 7.62mm)

Datasheet:: SN74AS258N.pdf

Description:: IC MULTIPLEXER 4 X 2:1 16DIP

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Product details

Overview

SN74AS258N 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 requiring high-speed signal routing and bus interface capability. It features A/B select control, output-enable (OE) input, and operates over 0°C to 70°C at V_CC = 4.5–5.5 V. It is used in digital logic subsystems where multiple 4-bit sources must share a common 4-bit data bus.

For engineers reviewing the SN74AS258N datasheet, SN74AS258N pinout, SN74AS258N application, or SN74AS258N equivalent, this page delivers verified electrical specs, timing performance, package mapping, functional role in bus arbitration, and validated alternative options - all grounded in TI's SDAS124C datasheet and official packaging documentation.

Technical Context

The SN74AS258N implements two independent 2:1 multiplexers per 4-bit channel, each selecting between inputs A and B under shared A/B select control. Its 3-state outputs enable direct connection to system buses without loading when OE is high, supporting bidirectional bus sharing in TTL-compatible logic systems.

It belongs to the 74AS logic family, delivering faster propagation delays (t_PLH/t_PHL ≤ 5 ns for data paths, ≤ 10 ns for OE control) and higher drive strength (I_OL = 48 mA, I_OH = −15 mA) than ALS variants, while maintaining pin compatibility with SN74ALS258A and SN74AS257 series devices.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	4.5 V to 5.5 V - Ensures stable operation across standard 5 V TTL supply rails with ±10% tolerance.
Propagation Delay (A/B → Y)	1 ns (min) / 5 ns (max) - Enables sub-5 ns signal routing critical for high-speed bus arbitration and synchronous logic design.
Output Drive (I_OL)	48 mA - Supports fan-out to ≥10 standard TTL loads or direct driving of small-bus segments without buffering.
3-State Enable/Disable Time	t_PZH/t_PHZ ≤ 8 ns - Guarantees fast bus release and acquisition, minimizing contention windows in time-multiplexed bus architectures.
Operating Temperature	0°C to 70°C - Qualified for commercial-grade embedded control, instrumentation, and industrial logic subsystems.
Input Voltage Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - Matches standard TTL logic levels for seamless integration with legacy 74-series components.
Power Dissipation (N package)	1.1 W max at T_A = 55°C - Defines thermal derating limits for through-hole PCB layouts with minimal copper area.

Pinout & Package

SN74AS258N uses a 16-pin plastic dual in-line package (PDIP-N), 300-mil width, with standard DIP footprint and through-hole mounting. Pin 1 is located at the top-left corner (notch-side left), with pins numbered counter-clockwise.

Pin/Terminal	Circuit Role	Design Meaning
1A, 2A, 3A, 4A	Data Input A (Channel 1–4)	First set of four 2:1 multiplexer inputs; selected when A/B = L.
1B, 2B, 3B, 4B	Data Input B (Channel 1–4)	Second set of four 2:1 multiplexer inputs; selected when A/B = H.
1Y, 2Y, 3Y, 4Y	3-State Output (Channel 1–4)	Active-high outputs disabled (high-impedance) when OE = H; driven low/high per selection when OE = L.
A/B	Common Select Control	Single-pin global select: L routes A inputs to Y; H routes B inputs to Y.
OE	Output Enable (Active-Low)	Drives all Y outputs into 3-state when high; enables outputs when low.
V_CC	Positive Supply	Connected to +5 V rail; decoupling capacitor required near pin 16.
GND	Ground Reference	System ground return; must be low-impedance path for noise immunity.

Key Features

Feature	Design Value
Dual 4-bit 2:1 multiplexing	Two independent 4-bit channels share one A/B select line - simplifies control logic in parallel data routing applications.
3-State bus-compatible outputs	Outputs enter high-impedance state when OE = H - eliminates need for external bus buffers in multi-source bus architectures.
AS-family speed grade	5 ns max propagation delay (A/B → Y) - outperforms ALS variants by >2×, enabling tighter timing margins in high-frequency control logic.
TTL-compatible input thresholds	V_IH ≥ 2.0 V, V_IL ≤ 0.8 V - ensures reliable interfacing with legacy 74LS, 74F, and microcontroller GPIO without level-shifting.
High-current drive capability	48 mA sink per output - supports direct connection to LEDs, small relays, or termination networks without external drivers.

Applications

Industrial PLC I/O Expansion	Legacy Bus Arbitration
Use Scenario: Adding modular analog/digital I/O modules to a programmable logic controller chassis with shared backplane data bus. IC Role / Device Role / Timing Role: SN74AS258N selects between local sensor data and host command data on each 4-bit bus segment, synchronized to system clock edges. Use Value: Enables deterministic, low-latency bus access with <5 ns switching - critical for real-time I/O response within 1 ms scan cycles.	Use Scenario: Resolving contention among multiple 4-bit peripheral controllers (e.g., UART, timer, ADC) sharing a common data bus in an 8051-based system. IC Role / Device Role / Timing Role: SN74AS258N acts as a priority-controlled bus switch, gated by OE from bus arbiter logic and A/B from address decode. Use Value: Eliminates external bus transceivers; 48 mA drive sustains signal integrity across 6-inch backplane traces at 10 MHz effective bus rate.
Test Equipment Signal Routing	Digital Logic Training Platform
Use Scenario: Configurable signal path selection in automated test equipment (ATE) for routing calibration signals or DUT outputs to measurement inputs. IC Role / Device Role / Timing Role: SN74AS258N serves as a reconfigurable 4-bit crosspoint switch, controlled via FPGA GPIO for dynamic path setup. Use Value: Sub-10 ns enable/disable times allow rapid reconfiguration (<100 ns) between test sequences without signal glitches or bus contention.	Use Scenario: Hands-on teaching of combinational logic, bus concepts, and 3-state behavior in university digital electronics labs. IC Role / Device Role / Timing Role: SN74AS258N demonstrates multiplexing, bus sharing, and tri-state control using tactile switches and LED indicators on breadboard platforms. Use Value: Robust 5 V TTL operation, visible pin labeling (SN74AS258N marking), and forgiving input thresholds simplify student debugging and reduce prototyping errors.

Industrial PLC I/O Expansion

Legacy Bus Arbitration

Use Scenario: Adding modular analog/digital I/O modules to a programmable logic controller chassis with shared backplane data bus.

IC Role / Device Role / Timing Role: SN74AS258N selects between local sensor data and host command data on each 4-bit bus segment, synchronized to system clock edges.

Use Value: Enables deterministic, low-latency bus access with <5 ns switching - critical for real-time I/O response within 1 ms scan cycles.

Use Scenario: Resolving contention among multiple 4-bit peripheral controllers (e.g., UART, timer, ADC) sharing a common data bus in an 8051-based system.

IC Role / Device Role / Timing Role: SN74AS258N acts as a priority-controlled bus switch, gated by OE from bus arbiter logic and A/B from address decode.

Use Value: Eliminates external bus transceivers; 48 mA drive sustains signal integrity across 6-inch backplane traces at 10 MHz effective bus rate.

Test Equipment Signal Routing

Digital Logic Training Platform

Use Scenario: Configurable signal path selection in automated test equipment (ATE) for routing calibration signals or DUT outputs to measurement inputs.

IC Role / Device Role / Timing Role: SN74AS258N serves as a reconfigurable 4-bit crosspoint switch, controlled via FPGA GPIO for dynamic path setup.

Use Value: Sub-10 ns enable/disable times allow rapid reconfiguration (<100 ns) between test sequences without signal glitches or bus contention.

Use Scenario: Hands-on teaching of combinational logic, bus concepts, and 3-state behavior in university digital electronics labs.

IC Role / Device Role / Timing Role: SN74AS258N demonstrates multiplexing, bus sharing, and tri-state control using tactile switches and LED indicators on breadboard platforms.

Use Value: Robust 5 V TTL operation, visible pin labeling (SN74AS258N marking), and forgiving input thresholds simplify student debugging and reduce prototyping errors.

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
SN74ALS258AN	ALS family: slower (max t_PLH = 8 ns), lower drive (I_OL = 24 mA), lower ICC (15.5 mA vs. 25.2 mA).	Suitable for cost-sensitive, lower-speed systems where <10 MHz bus rates suffice and power budget is constrained.	Select SN74ALS258AN only if timing margin allows ≥3 ns additional delay and load drive ≤24 mA per output.
SN74AS257N	Same AS family, but dual 4-bit 2:1 with independent A/B selects per channel (vs. shared A/B in SN74AS258N).	Required when per-channel select control is needed (e.g., independent source selection per data lane); not drop-in compatible.	Choose SN74AS257N only when design requires individual A/B control per 4-bit group - pinout differs (no shared A/B pin).

Compared with SN74ALS258AN, SN74AS258N delivers 60% faster switching and double the sink current, justifying its use in timing-critical bus interfaces; versus SN74AS257N, it trades per-channel select flexibility for simplified control logic and identical pinout with SN74ALS258A.

Availability

SN74AS258N is available at Aetrix Electronics and suitable for industrial PLC expansion, legacy bus arbitration, test equipment signal routing, and digital training platforms requiring stable component supply and long-term obsolescence management.

Supply support for SN74AS258N 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 SN74AS258N belongs to TI's 74AS advanced Schottky TTL logic family, engineered for high-speed digital control systems requiring robust noise immunity, fast bus switching, and backward compatibility with legacy 5 V TTL infrastructure.

FAQ

What is the function of the A/B pin on the SN74AS258N?

The A/B pin is a common select control for both 4-bit multiplexer sections. When A/B = LOW, inputs 1A–4A are routed to outputs 1Y–4Y; when A/B = HIGH, inputs 1B–4B are routed instead. This single-pin global selection simplifies control logic versus per-channel select architectures like those in SN74AS257N.

Does the SN74AS258N support 3.3 V operation?

No. The SN74AS258N is specified only for V_CC = 4.5 V to 5.5 V and is not 3.3 V tolerant. Its input thresholds (V_IH ≥ 2.0 V, V_IL ≤ 0.8 V) and output drive characteristics are optimized for 5 V TTL systems. For 3.3 V logic, consider modern CMOS alternatives such as SN74LVC257A.

How does the SN74AS258N differ from the SN74AS257N?

The SN74AS258N uses a shared A/B select line for both 4-bit sections, while the SN74AS257N provides independent A/B controls per section. Their pinouts differ: SN74AS258N has one A/B pin (pin 15), whereas SN74AS257N has two (pins 1 and 15). They are not pin-compatible replacements.

What is the maximum capacitive load the SN74AS258N can drive reliably?

The SN74AS258N's switching characteristics (t_PLH, t_PHL) are characterized at C_L = 50 pF. While it can drive heavier loads, signal integrity degrades beyond this value - rise/fall times increase and propagation delay rises nonlinearly. For >50 pF, add series termination or buffer stages.

Is the SN74AS258N RoHS compliant?

Yes. Per TI's Package Option Addendum, SN74AS258N is marked "Yes" for RoHS compliance, with lead finish NIPDAU (nickel/palladium/gold) and no lead (Pb)-based solder. It meets EU Directive 2011/65/EU and is suitable for environmentally regulated production.

SN74AS258N Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74AS

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

SN74AS258N FAQ

1.How can I place an order for SN74AS258N through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74AS258N 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 SN74AS258N reliable?

The price and inventory of SN74AS258N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS258N is usually 5 days.

3.What payment methods are accepted for SN74AS258N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS258N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74AS258N?

SN74AS258N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74AS258N 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 SN74AS258N?

For technical support, including SN74AS258N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS258N requirements.

6.How does Aetrix verify that SN74AS258N is sourced from the original manufacturer or authorized distributors?

All SN74AS258N 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 SN74AS258N meets industry standards.

7.What is the process for return or replacement of SN74AS258N?

All SN74AS258N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS258N, 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 SN74AS258N part is unused and in its original packaging.

Return procedure for SN74AS258N:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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