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

Texas Instruments SN74LS157DG4

Name: SN74LS157DG4
Brand: Texas Instruments
SKU: SN74LS157DG4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74LS157DG4

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: SN74LS157DG4.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:1,794

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Product details

Overview

SN74LS157DG4 from Texas Instruments is a quad 2-line-to-1-line data selector/multiplexer in a 16-pin SOIC package, operating at 0°C to 70°C, with typical propagation delay of 15 ns and supply current of 19 mA. It performs logic-level signal routing in digital control systems, bus management, and address/data path selection.

For engineers reviewing the SN74LS157DG4 datasheet, SN74LS157DG4 pinout, SN74LS157DG4 application, or SN74LS157DG4 equivalent, key selection criteria include TTL-compatible input thresholds, guaranteed fan-out of 20 LS-TTL loads, complementary enable control, and compatibility with legacy 74LS logic families in industrial and test equipment designs.

Technical Context

The SN74LS157DG4 implements four independent 2:1 multiplexers sharing a common strobe (G̅) input and two complementary select lines (S and S̅). Each channel routes either A or B input to Y output based on S state, with active-low enable asserting all outputs to high-impedance when G̅ = HIGH.

It uses bipolar Schottky TTL technology for noise immunity and speed-power balance, supports wired-OR expansion via Y outputs, and maintains consistent timing across channels-critical for synchronized data path switching in microprocessor peripheral interfaces and digital instrumentation.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	74LS TTL - ensures interoperability with legacy LS-series logic and predictable DC noise margins.
Propagation Delay (t_pd)	15 ns max (V_CC = 5 V, T_A = 25°C) - enables reliable operation in 33-MHz synchronous control paths.
Fan-Out	20 LS-TTL loads - supports direct drive of multiple downstream gates without buffering.
Supply Voltage (V_CC)	4.75 V to 5.25 V - matches standard TTL power rail tolerance and avoids marginal operation.
Input Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - guarantees robust recognition of logic LOW/HIGH from CMOS or other TTL sources.
Output Drive	I_OL = 8 mA, I_OH = –0.4 mA - sufficient to sink LED indicators or drive small capacitive loads (<15 pF).

Pinout & Package

SN74LS157DG4 is housed in a 16-pin SOIC (D) package, 7.5 mm wide, with 1.27 mm pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot; device orientation follows JEDEC MS-012 standard.

Pin/Terminal	Circuit Role	Design Meaning
1 (G̅)	Active-low strobe enable	When HIGH, forces all Y outputs into high-impedance; LOW enables multiplexer function.
2–5, 9–12 (A1–A4, B1–B4)	Data inputs	Four pairs of independent 2-input channels; A and B represent alternate source signals per channel.
6, 7 (S, S̅)	Select control pair	S selects A→Y; S̅ (inverted S) is provided internally - only one external select line needed.
8 (GND)	Ground reference	Common return for all logic and output currents; must be low-inductance connection.
13–16 (Y1–Y4)	Outputs	Active-high, non-inverting multiplexed outputs; electrically compatible with LS-TTL inputs.
16 (V_CC)	Power supply	5 V nominal supply; requires local 0.1 µF ceramic decoupling adjacent to pin.

Key Features

Feature	Design Value
Quad 2:1 multiplexer architecture	Enables simultaneous routing of four independent data pairs using shared select and enable - reduces component count in bus arbitration circuits.
Complementary select input (S/S̅)	Eliminates need for external inverter; simplifies PCB layout and timing alignment in synchronous systems.
Three-state outputs with common enable	Allows direct connection of multiple SN74LS157DG4 devices to a shared bus without contention during disable.
TTL-compatible input/output levels	Interoperates seamlessly with 74LS, 74ALS, and 74F families without level-shifting circuitry.
Guaranteed AC/DC specifications over temperature	Validated from 0°C to 70°C - suitable for commercial-grade embedded controllers and lab instrumentation.

Applications

Microprocessor Address Decoding	Digital Test Equipment Signal Routing
Use Scenario: Selecting between two memory-mapped peripheral address ranges during CPU read/write cycles. IC Role / Device Role / Timing Role: Acts as address-path multiplexer, synchronizing with CPU control signals to isolate I/O space from memory space. Use Value: Reduces gate count versus discrete logic solutions while maintaining sub-20 ns setup/hold timing margins.	Use Scenario: Switching stimulus signals between DUT pins and measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: Provides deterministic, glitch-free signal path selection under programmable controller command. Use Value: Enables reconfigurable test head architecture with single-chip routing for up to four parallel signal channels.
Industrial PLC I/O Multiplexing	Legacy Bus Interface Logic
Use Scenario: Consolidating multiple sensor input streams onto a shared ADC interface in programmable logic controllers. IC Role / Device Role / Timing Role: Functions as analog front-end digital selector, coordinating with sample clock and conversion start signals. Use Value: Maintains channel-to-channel timing skew below 1 ns - critical for synchronized multi-channel acquisition.	Use Scenario: Adapting legacy 8-bit data buses to newer controller architectures requiring dynamic bus partitioning. IC Role / Device Role / Timing Role: Serves as bidirectional bus switch controller, managing direction and enable states for data flow arbitration. Use Value: Preserves signal integrity across 15 cm traces at 10 MHz due to controlled output drive strength and low capacitance.

Microprocessor Address Decoding

Digital Test Equipment Signal Routing

Use Scenario: Selecting between two memory-mapped peripheral address ranges during CPU read/write cycles.

IC Role / Device Role / Timing Role: Acts as address-path multiplexer, synchronizing with CPU control signals to isolate I/O space from memory space.

Use Value: Reduces gate count versus discrete logic solutions while maintaining sub-20 ns setup/hold timing margins.

Use Scenario: Switching stimulus signals between DUT pins and measurement instruments in automated test fixtures.

IC Role / Device Role / Timing Role: Provides deterministic, glitch-free signal path selection under programmable controller command.

Use Value: Enables reconfigurable test head architecture with single-chip routing for up to four parallel signal channels.

Industrial PLC I/O Multiplexing

Legacy Bus Interface Logic

Use Scenario: Consolidating multiple sensor input streams onto a shared ADC interface in programmable logic controllers.

IC Role / Device Role / Timing Role: Functions as analog front-end digital selector, coordinating with sample clock and conversion start signals.

Use Value: Maintains channel-to-channel timing skew below 1 ns - critical for synchronized multi-channel acquisition.

Use Scenario: Adapting legacy 8-bit data buses to newer controller architectures requiring dynamic bus partitioning.

IC Role / Device Role / Timing Role: Serves as bidirectional bus switch controller, managing direction and enable states for data flow arbitration.

Use Value: Preserves signal integrity across 15 cm traces at 10 MHz due to controlled output drive strength and low capacitance.

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
SN74LS257N	Same logic function and pinout, but features complementary outputs (Y and Y̅) per channel.	Required where inverted output is needed without external inverters - e.g., differential bus drivers.	Choose SN74LS257N only if dual-rail output capability is essential; otherwise SN74LS157DG4 offers lower part count.
SN74HC157DR	CMOS version with wider V_CC range (2 V–6 V), lower I_CC (8 µA), but higher t_pd (25 ns typ).	Suitable for battery-powered or mixed-voltage systems; not drop-in due to different input thresholds and drive strength.	Select SN74HC157DR for low-power or 3.3 V–5 V hybrid designs; avoid in noise-sensitive or high-speed LS-only environments.

Compared with SN74LS257N and SN74HC157DR, the SN74LS157DG4 delivers optimal balance of speed, drive strength, and legacy compatibility for fixed 5 V TTL systems - especially where board space, cost, and signal integrity are prioritized over power savings or dual outputs.

Availability

SN74LS157DG4 is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, and legacy system upgrades requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS157DG4 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 ICs with broad industrial and automotive qualification.

The SN74LS157DG4 belongs to TI's legacy 74LS logic family, engineered for reliability and interoperability in commercial-grade digital systems where deterministic timing and proven field performance are critical.

FAQ

What is the maximum operating frequency supported by SN74LS157DG4?

The SN74LS157DG4 does not specify a maximum clock frequency in its datasheet because it is a combinational logic device without internal clocking. Its usable switching rate is determined by propagation delay (15 ns max) and system-level timing margins. In practice, SN74LS157DG4 reliably supports data rates up to approximately 33 MHz in well-designed PCB layouts with proper termination and decoupling.

Can SN74LS157DG4 be used with 3.3 V logic systems?

No - SN74LS157DG4 is designed exclusively for 5 V TTL operation (4.75 V–5.25 V). Its input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and output drive characteristics are incompatible with 3.3 V CMOS or LVTTL signaling. Using SN74LS157DG4 in a 3.3 V system risks undetected logic errors or excessive current draw; a level translator or SN74HC157-based solution is required.

Does SN74LS157DG4 support hot-swap or live-insertion?

No - SN74LS157DG4 lacks hot-swap protection circuitry such as power-up sequencing control, I_OFF isolation, or bus-hold. Applying V_CC while signals are present may cause latch-up or excessive ground current. For hot-swap applications, consider purpose-built bus switches like the SN74CBT16210 or redesign with series resistors and controlled power sequencing.

How does the enable (G̅) pin affect output behavior in SN74LS157DG4?

When G̅ is HIGH, all four Y outputs enter high-impedance (Hi-Z) state regardless of S or input values - effectively disconnecting the device from the bus. When G̅ is LOW, outputs reflect the selected A/B inputs per channel. This enables bus-sharing among multiple SN74LS157DG4 devices, with only one enabled at a time to prevent contention.

Is SN74LS157DG4 RoHS compliant?

Yes - SN74LS157DG4 carries "Yes" in the RoHS column of TI's official packaging documentation, indicating compliance with Directive 2011/65/EU. It uses NiPdAu (NIPDAU) lead finish and meets exemption requirements for lead in high-melting-temperature solder alloys. Full compliance documentation is available in TI's RoHS Certificate of Compliance for this orderable part number.

SN74LS157DG4 Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74LS

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:: 400µA, 8mA

Voltage Supply Source:: Single Supply

Voltage - Supply:: 4.75V ~ 5.25V

Operating Temperature:: 0°C ~ 70°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

SN74LS157DG4 FAQ

1.How can I place an order for SN74LS157DG4 through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74LS157DG4 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 SN74LS157DG4 reliable?

The price and inventory of SN74LS157DG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS157DG4 is usually 5 days.

3.What payment methods are accepted for SN74LS157DG4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS157DG4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74LS157DG4?

SN74LS157DG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74LS157DG4 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 SN74LS157DG4?

For technical support, including SN74LS157DG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS157DG4 requirements.

6.How does Aetrix verify that SN74LS157DG4 is sourced from the original manufacturer or authorized distributors?

All SN74LS157DG4 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 SN74LS157DG4 meets industry standards.

7.What is the process for return or replacement of SN74LS157DG4?

All SN74LS157DG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS157DG4, 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 SN74LS157DG4 part is unused and in its original packaging.

Return procedure for SN74LS157DG4:

1.Submit a request within 90 days.

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

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