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Texas Instruments SN74LS157NG4
- Part No.:
- SN74LS157NG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74LS157NG4.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,401
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Product details
Overview
SN74LS157NG4 from Texas Instruments is a quad 2-line-to-1-line data selector/multiplexer in a 16-pin PDIP package, operating at 0°C to 70°C, with TTL-compatible inputs and outputs, typical propagation delay of 15 ns at VCC = 5 V, and fan-out capability of 10 LS-TTL loads. It enables digital signal routing in bus management and data path control applications.
For engineers reviewing the SN74LS157NG4 datasheet, SN74LS157NG4 pinout, SN74LS157NG4 application, or SN74LS157NG4 equivalent, key selection criteria include its single-enable control architecture, complementary output pairs per channel, guaranteed noise margin of 0.4 V (min), and compatibility with legacy 74LS logic families in industrial control and test equipment designs.
Technical Context
The SN74LS157NG4 integrates four independent 2:1 multiplexers sharing a common strobe (enable) input and complementary output terminals (Y and Y̅). Each channel selects between two data inputs (A and B) based on the select line state, with active-low enable asserting all outputs to high-impedance when disabled.
It uses bipolar Schottky TTL technology, delivering consistent switching thresholds (VIH = 2.0 V min, VIL = 0.8 V max), output drive strength (IOH = –0.4 mA, IOL = 8 mA), and DC noise immunity across its specified temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS TTL - ensures interoperability with standard LS-series components and predictable timing behavior in mixed-logic systems. |
| Supply Voltage | VCC = 4.75 V to 5.25 V - supports stable operation under nominal 5-V rail with ±5% tolerance, critical for legacy board-level power integrity. |
| Propagation Delay | tPD = 15 ns (max) - defines worst-case signal path latency for synchronous data routing in control-state machines and address decoding. |
| Output Drive | IOL = 8 mA / IOH = –0.4 mA - sufficient to directly drive 10 LS-TTL inputs without buffering, reducing component count in discrete logic designs. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade environments including office automation, instrumentation, and non-military embedded controllers. |
| Input Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - provides robust noise margin against crosstalk and ground bounce in densely routed PCBs. |
Pinout & Package
SN74LS157NG4 is housed in a 16-pin plastic dual in-line package (PDIP-N), 0.300-inch body width, with through-hole mounting and industry-standard pin spacing (0.100 inch).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (1G) | Active-low enable input | Disables all four multiplexer outputs (Y/Y̅) to high-impedance when high; required for bus isolation in shared-data-path architectures. |
| 2–3, 4–5, 10–11, 12–13 (1A/1B, 2A/2B, 3A/3B, 4A/4B) | Data input pairs | Four independent 2-input channels; each pair feeds one multiplexer stage, supporting parallel data selection across multiple signals. |
| 6, 7, 8, 9 (1Y, 2Y, 3Y, 4Y) | True outputs | Active-high selected outputs; used for direct connection to downstream logic or bus lines without inversion. |
| 14, 15, 16, 1 (1Y̅, 2Y̅, 3Y̅, 4Y̅) | Complementary outputs | Active-low inverted outputs; enables differential signaling or simplifies OR/NOR logic implementation without external inverters. |
| 16 (VCC) | Positive supply | 5-V power connection; decoupling capacitor placement near this pin is essential to suppress switching noise in multi-channel operation. |
| 8 (GND) | Ground reference | Common return path for all internal circuits; must be low-impedance and tied to system ground plane to maintain noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Quad 2:1 multiplexer function | Integrates four independent data selectors in one IC, reducing board space and interconnect complexity versus discrete gate implementations. |
| Complementary outputs per channel | Provides both true and inverted outputs simultaneously, eliminating need for external inverters in applications requiring dual-polarity logic levels. |
| Single active-low enable | Allows synchronized disabling of all outputs with one control signal-critical for time-multiplexed bus arbitration and power-gated subsystems. |
| TTL-compatible input thresholds | Ensures reliable interfacing with 74LS, 74S, and 74F logic families without level-shifting circuitry in mixed-technology designs. |
| High noise immunity | Guaranteed 0.4 V DC noise margin supports stable operation in electrically noisy industrial enclosures and test fixtures. |
Applications
| Industrial Control Logic | Test Equipment Signal Routing |
|---|---|
|
Use Scenario: Selecting between sensor calibration and live measurement data streams in programmable logic controllers. IC Role / Device Role / Timing Role: Data path selector enabling real-time mode switching without CPU intervention or clock domain crossing. Use Value: Reduces firmware overhead by offloading signal routing to hardware, improving deterministic response time in closed-loop control cycles. |
Use Scenario: Routing DUT (device under test) output signals to multiple measurement instruments (oscilloscope, logic analyzer, DMM) via front-panel switches. IC Role / Device Role / Timing Role: Manual or microcontroller-controlled signal multiplexer providing glitch-free path selection during instrument reconfiguration. Use Value: Eliminates mechanical switch wear and contact bounce while maintaining sub-20 ns signal integrity across all selected paths. |
| Legacy Computer Bus Management | Embedded System Address Decoding |
|
Use Scenario: Arbitrating access to shared memory or peripheral buses among multiple DMA controllers in retro-computing platforms. IC Role / Device Role / Timing Role: Bus multiplexer coordinating concurrent read/write requests using strobe-synchronized output gating. Use Value: Enables clean bus handoff with no contention windows, preserving data integrity in 8-bit ISA-style architectures. |
Use Scenario: Generating chip-select signals for multiple memory-mapped peripherals (UART, ADC, GPIO) based on upper address bits. IC Role / Device Role / Timing Role: Address decoder element translating 2-bit select codes into four discrete enable lines with simultaneous assertion. Use Value: Simplifies address decode logic tree, reduces gate count, and improves timing predictability versus NAND-based solutions. |
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 |
|---|---|---|---|
| SN74LS158N | Includes built-in inverter on select line; outputs are active-low only (no complementary Y/Y̅ pairs). | Suitable where inverted-only outputs simplify downstream logic but precludes true/inverted dual-path usage. | Select SN74LS158N only if system design requires inverted outputs exclusively and can accommodate missing Y̅ pins. |
| SN74HC157N | CMOS family; wider VCC range (2 V–6 V), lower ICC, higher noise margin (≥30% VCC), but slower tPD (21 ns typ at 4.5 V). | Better for mixed-voltage or battery-powered systems, but timing-critical 5-V TTL designs may require validation. | Choose SN74HC157N for new designs targeting lower power or broader supply flexibility; retain SN74LS157NG4 for drop-in replacement in existing LS-based layouts. |
Compared with SN74LS157NG4, SN74LS158N trades complementary outputs for integrated select inversion-reducing external logic but limiting signal polarity options-while SN74HC157N offers CMOS advantages at the cost of timing compatibility and requires careful evaluation of drive strength and transition rate matching in legacy TTL systems.
Availability
SN74LS157NG4 is available at Aetrix Electronics and suitable for industrial control logic, test equipment signal routing, legacy computer bus management, and embedded system address decoding requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74LS157NG4 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 specializing in analog, embedded processing, and logic technologies, with over 50 years of innovation in industrial, automotive, and communications markets.
The SN74LS157NG4 belongs to TI's legacy 74LS logic family, engineered for reliability and interoperability in fixed-function digital systems where deterministic timing, proven field performance, and backward compatibility are prioritized over ultra-low power or high-speed operation.
FAQ
What is the maximum operating frequency supported by the SN74LS157NG4?
The SN74LS157NG4 does not specify a maximum clock or toggle frequency in its datasheet; it is designed for combinational data selection rather than synchronous clocked operation. Its usable data rate is governed by propagation delay (15 ns max) and system setup/hold timing constraints-typically supporting reliable operation up to approximately 30 MHz in well-designed PCB layouts with controlled trace lengths and proper termination.
Does the SN74LS157NG4 support hot insertion or live insertion into powered systems?
No, the SN74LS157NG4 is not designed for hot insertion. Its absolute maximum ratings do not include provisions for back-powering or sequential pin engagement, and applying VCC after signal inputs may cause latch-up or excessive current draw. Power sequencing-VCC applied before any input signals-is required for safe operation of SN74LS157NG4 in all applications.
Can the SN74LS157NG4 be used with 3.3-V logic interfaces?
The SN74LS157NG4 is a 5-V-only TTL device and is not 3.3-V tolerant. Applying 3.3-V signals to its inputs violates the minimum VIH specification (2.0 V min) and risks unreliable switching or increased static current. Interfacing with 3.3-V systems requires level-shifting circuitry; SN74LS157NG4 must be operated strictly at VCC = 4.75–5.25 V with compatible 5-V logic sources.
How does the enable (1G) pin affect output states on the SN74LS157NG4?
When the active-low enable pin (1G) is high, all four Y and Y̅ outputs enter high-impedance (Hi-Z) state regardless of select or input conditions-effectively disconnecting the device from the bus. When 1G is low, outputs respond normally to select and data inputs. This feature allows SN74LS157NG4 to share signal lines safely with other devices in wired-OR or multidrop configurations.
Is the SN74LS157NG4 RoHS compliant?
Yes, the SN74LS157NG4 is RoHS compliant, featuring lead-free NiPdAu (NIPDAU) lead finish and meeting EU Directive 2011/65/EU requirements. The "G4" suffix explicitly denotes TI's green packaging standard, confirming absence of lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE substances above threshold limits.
SN74LS157NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74LS157NG4 FAQ
1.How can I place an order for SN74LS157NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS157NG4 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 SN74LS157NG4 reliable?
The price and inventory of SN74LS157NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS157NG4 is usually 5 days.
3.What payment methods are accepted for SN74LS157NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS157NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS157NG4?
SN74LS157NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS157NG4 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 SN74LS157NG4?
For technical support, including SN74LS157NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS157NG4 requirements.
6.How does Aetrix verify that SN74LS157NG4 is sourced from the original manufacturer or authorized distributors?
All SN74LS157NG4 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 SN74LS157NG4 meets industry standards.
7.What is the process for return or replacement of SN74LS157NG4?
All SN74LS157NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS157NG4, 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 SN74LS157NG4 part is unused and in its original packaging.
Return procedure for SN74LS157NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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