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Texas Instruments SN74ALS158N
- Part No.:
- SN74ALS158N
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS158N.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,394
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Product details
Overview
SN74ALS158N from Texas Instruments is a quad 2-line-to-1-line data selector/multiplexer with inverted output logic, designed for high-speed TTL-compatible digital systems. It features buffered inputs/outputs, 16-pin PDIP packaging, operates from 4.5 V to 5.5 V, delivers 8 mA low-level output drive, and supports 0°C to 70°C industrial temperature range - used in address/data routing within legacy microprocessor bus interfaces.
For engineers reviewing the SN74ALS158N datasheet, SN74ALS158N pinout, SN74ALS158N application, or SN74ALS158N equivalent, key selection criteria include propagation delay (tPHL/tPLH ≤ 18 ns), inverted output behavior versus true-output variants like SN74ALS157N, and compatibility with standard 5-V TTL logic families in multiplexed control path designs.
Technical Context
The SN74ALS158N implements four independent 2:1 multiplexers sharing a common strobe (G) and select (A/B) input. Each channel selects between two data sources (A or B) and routes the inverted signal to its corresponding Y output. Internal inverters and drivers minimize propagation delay while maintaining full TTL noise margin compliance.
Its logic function is defined by the truth table where G = HIGH enables outputs, A/B = LOW selects input A, and all outputs are inverted relative to selected inputs. Unlike the SN74ALS157N, this device provides complementary output polarity - critical for timing-critical paths where inversion eliminates external gate requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5-V TTL rails with ±10% tolerance. |
| Propagation Delay | tPHL/tPLH ≤ 18 ns (VCC = 5 V, CL = 50 pF) - enables reliable operation in 20-MHz+ synchronous bus environments. |
| Output Drive | IOL = 8 mA, IOH = −0.4 mA - sufficient to drive 10 standard TTL loads without buffering. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL voltage levels for seamless interfacing. |
| Operating Temperature | 0°C to 70°C - qualified for commercial/industrial embedded control applications. |
| Package Type | 16-pin PDIP (N) - through-hole mounting compatible with legacy PCB assembly and prototyping. |
Pinout & Package
SN74ALS158N uses a 16-pin plastic dual in-line package (PDIP), 300-mil width, with standard DIP footprint and lead spacing of 0.1 inch. Pin 1 is located at the top-left corner when viewed from the top with notch or dot orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 9, 10, 12, 13 | Data Inputs (1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B) | Eight independent data inputs grouped into four pairs; each pair feeds one multiplexer channel. |
| 3, 6, 8, 11 | Outputs (1Y, 2Y, 3Y, 4Y) | Inverted outputs - logic state is complement of selected input (A or B) when enabled. |
| 7 | GND | Ground reference for all internal circuitry and I/O. |
| 14 | VCC | Positive supply rail (4.5–5.5 V) powering internal logic and output drivers. |
| 15 | G (Strobe) | Active-HIGH enable - all outputs go HIGH-Z when G = LOW, regardless of A/B or data inputs. |
| 16 | A/B (Select) | Common select line - LOW chooses A inputs, HIGH chooses B inputs across all four channels. |
Key Features
| Feature | Design Value |
|---|---|
| Inverted Output Logic | Eliminates need for external inverters in feedback or complemented-data paths, reducing component count and board space. |
| Buffered Inputs/Outputs | Improves noise immunity and fan-out capability, supporting direct connection to multiple downstream TTL gates. |
| Low Propagation Delay | Typical tPHL = 5 ns (VCC = 5 V) enables use in high-speed address/data switching within 8-bit microcontroller systems. |
| Strobe-Controlled Output Disable | G input forces all Y outputs into high-impedance state, allowing shared bus operation without contention. |
| TTL-Compatible Interface | Meets standard TTL VIH/VIL thresholds and drive strength, ensuring plug-in compatibility with legacy 74-series logic. |
Applications
| Microprocessor Address Decoding | Legacy Bus Arbitration |
|---|---|
|
Use Scenario: Selecting between two memory-mapped peripheral address ranges during CPU read/write cycles. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer routing address bits under A/B and G control to generate chip-select signals. Use Value: Inverted outputs align directly with active-low enable inputs on many legacy peripherals, eliminating discrete inverters. |
Use Scenario: Managing shared data bus access among multiple DMA controllers in an ISA-style backplane system. IC Role / Device Role / Timing Role: Strobe-gated data path selector enabling/disabling data flow from competing masters. Use Value: G-input high-impedance disable prevents bus contention; 8 mA drive supports full TTL bus loading. |
| Digital Test Equipment Signal Routing | Industrial PLC I/O Multiplexing |
|
Use Scenario: Switching calibration reference signals or sensor inputs into a common ADC channel in automated test fixtures. IC Role / Device Role / Timing Role: Precision analog-digital interface multiplexer with deterministic propagation delay and low crosstalk. Use Value: Matched tPHL/tPLH (≤18 ns) ensures consistent sampling window alignment across all four channels. |
Use Scenario: Consolidating discrete sensor inputs (e.g., limit switches, proximity sensors) onto fewer controller input lines. IC Role / Device Role / Timing Role: Industrial-grade data selector operating reliably across 0°C–70°C ambient with robust ESD-tolerant inputs. Use Value: Buffered inputs reject noise from electrically noisy factory environments; PDIP package supports wave-solder reworkability. |
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 |
|---|---|---|---|
| SN74ALS157N | Provides true (non-inverted) outputs; otherwise identical pinout, timing, and electrical specs. | Used where downstream logic expects non-inverted data; requires external inversion if complemented signal needed. | Select SN74ALS157N when output polarity must match input logic state; verify downstream interface compatibility. |
| SN74AS158N | Faster propagation delay (tPHL/tPLH ≤ 4.5 ns), higher ICC (15.6–22.5 mA), same inverted output behavior and pinout. | Suitable for higher-speed systems requiring sub-5-ns channel switching; increased power draw limits use in thermally constrained designs. | Choose SN74AS158N only when speed gain justifies added power and thermal budget; confirm VCC stability under peak load. |
Compared with SN74ALS157N and SN74AS158N, the SN74ALS158N offers optimal balance of speed, power efficiency, and inverted-output functionality for cost-sensitive industrial control and legacy computing applications where 18-ns delay is acceptable and polarity matching simplifies design.
Availability
SN74ALS158N is available at Aetrix Electronics and suitable for microprocessor address decoding, legacy bus arbitration, digital test equipment signal routing, and industrial PLC I/O multiplexing requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS158N 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 broad industrial, automotive, and communications portfolio coverage.
The SN74ALS158N belongs to TI's 74ALS advanced low-power Schottky logic family, engineered for improved speed-power trade-offs over standard TTL in mid-1980s digital systems - targeting reliability-critical control and interface applications.
FAQ
What is the primary logic function of the SN74ALS158N?
The SN74ALS158N is a quad 2-line-to-1-line data selector/multiplexer that routes one of two input signals (A or B) per channel to its corresponding output (Y), with all outputs inverted. Selection is controlled by the common A/B pin, and all channels are enabled or disabled simultaneously via the strobe (G) input. This function is explicitly defined in the device's truth table and logic diagram in the SDAS081C datasheet.
Does the SN74ALS158N support 3.3-V operation?
No, the SN74ALS158N does not support 3.3-V operation. Its recommended supply voltage range is strictly 4.5 V to 5.5 V, and absolute maximum VCC is 7 V. Operation below 4.5 V risks incorrect logic thresholds and degraded noise margins, as confirmed by the "Recommended Operating Conditions" table in the SDAS081C datasheet. For 3.3-V systems, consider modern CMOS alternatives such as the SN74LVC157A.
How does the SN74ALS158N differ from the SN74ALS157N?
The SN74ALS158N differs from the SN74ALS157N solely in output polarity: SN74ALS158N provides inverted outputs (Y = NOT(selected input)), while SN74ALS157N provides true outputs (Y = selected input). All other parameters - pinout, timing, drive strength, supply range, and temperature rating - are identical. This distinction is clearly stated in the device description and function table of the SDAS081C datasheet.
What is the maximum capacitive load the SN74ALS158N can drive reliably?
The SN74ALS158N is characterized for CL = 50 pF in its switching characteristics tables, with guaranteed tPHL/tPLH performance up to that load. While it may drive heavier loads, timing degradation and potential signal integrity issues occur beyond 50 pF. The datasheet does not specify derating curves or safe operating area for higher capacitance, so 50 pF remains the validated design limit for guaranteed timing compliance.
Is the SN74ALS158N RoHS compliant?
Yes, the SN74ALS158N is RoHS compliant. According to TI's Package Option Addendum (dated 15-Jul-2026), the SN74ALS158N ordering variant carries "Yes" in the RoHS column and uses NIPDAU (nickel-palladium-gold) lead finish. This confirms full compliance with EU Directive 2011/65/EU and related restrictions on hazardous substances.
SN74ALS158N 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:
- 400µA, 8mA
- 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
SN74ALS158N FAQ
1.How can I place an order for SN74ALS158N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS158N 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 SN74ALS158N reliable?
The price and inventory of SN74ALS158N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS158N is usually 5 days.
3.What payment methods are accepted for SN74ALS158N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS158N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS158N?
SN74ALS158N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS158N 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 SN74ALS158N?
For technical support, including SN74ALS158N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS158N requirements.
6.How does Aetrix verify that SN74ALS158N is sourced from the original manufacturer or authorized distributors?
All SN74ALS158N 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 SN74ALS158N meets industry standards.
7.What is the process for return or replacement of SN74ALS158N?
All SN74ALS158N units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS158N, 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 SN74ALS158N part is unused and in its original packaging.
Return procedure for SN74ALS158N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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