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Texas Instruments SN74AHCT157N
- Part No.:
- SN74AHCT157N
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AHCT157N.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,495
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Product details
Overview
SN74AHCT157N from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in 16-pin PDIP package, operating at 4.5V–5.5V VCC, with TTL-compatible inputs, active-low strobe (G), true outputs, and propagation delays as low as 4.1 ns (CL = 15 pF). It routes four independent 2-input data channels based on a common select line, used in digital logic consolidation, bus arbitration, and signal routing in industrial control and instrumentation systems.
For engineers reviewing the SN74AHCT157N datasheet, SN74AHCT157N pinout, SN74AHCT157N application, or SN74AHCT157N equivalent, this page delivers verified electrical specs, validated PDIP package dimensions, functional mode truth table, real-world use cases, and two confirmed alternative parts with documented differences for reliable selection in 5V logic designs.
Technical Context
The SN74AHCT157N implements four independent 2:1 multiplexers sharing one address-select input (A/B) and one active-low output strobe (G). When G is high, all Y outputs are forced low regardless of A/B or data inputs; when G is low, each Yn selects between corresponding An and Bn based on the A/B state. All outputs are non-inverting and fully buffered.
It uses advanced CMOS technology with TTL-voltage-compatible inputs (VIH = 2 V, VIL = 0.8 V), supports latch-up immunity >250 mA per JESD17, and operates across –40°C to +85°C ambient temperature. Input transition rate is specified at ≤20 ns/V to ensure clean switching under fast-edge conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V logic rails and tolerance to supply ripple. |
| Propagation Delay (tPLH/tPHL) | 4.1 ns min / 7.5 ns max (CL = 15 pF) - Enables high-speed data routing in synchronous 50+ MHz digital systems. |
| Output Drive | ±8 mA - Sufficient to drive multiple 74-series TTL/CMOS loads without external buffering. |
| Input Voltage Thresholds | VIH = 2 V, VIL = 0.8 V - Guarantees robust interfacing with legacy TTL outputs and noise margin ≥0.4 V. |
| Power Dissipation Capacitance | 11 pF - Predictable dynamic power consumption for timing analysis and thermal estimation. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade embedded applications without derating. |
| Supply Current (ICC) | 2 μA typical (VCC = 5.5 V, TA = 25°C) - Ultra-low static power ideal for always-on logic sections. |
Pinout & Package
SN74AHCT157N is housed in a 16-pin plastic dual in-line package (PDIP-N), 19.1 mm × 6.6 mm body size, 22.2 mm × 7.6 mm overall footprint including leads, 3.3 mm nominal lead length, and 2.54 mm lead pitch. RoHS-compliant with NIPDAU lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A/B | Address select input | Common control for all four multiplexers: selects source A (low) or B (high) for each channel. |
| 1A–4A | Data input A (channels 1–4) | First set of four independent data inputs routed to Y outputs when A/B = low. |
| 1B–4B | Data input B (channels 1–4) | Second set of four independent data inputs routed to Y outputs when A/B = high. |
| 1Y–4Y | Data output (channels 1–4) | True (non-inverted) outputs reflecting selected A or B input per channel. |
| G | Active-low strobe input | Global enable: outputs go low when G = high; data passes only when G = low. |
| VCC | Positive supply | Primary 4.5–5.5 V power rail; requires local 0.1 µF bypass capacitor. |
| GND | Ground reference | Return path for all signals and supply current; must be low-impedance connection. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard TTL logic levels (0.8 V/2.0 V thresholds) without level-shifting circuitry. |
| Common strobe control | Single G input disables all outputs simultaneously-critical for bus contention prevention. |
| True (non-inverting) outputs | Eliminates need for external inverters in signal paths requiring polarity preservation. |
| Latch-up immunity | Exceeds 250 mA per JESD17-ensures reliability in noisy industrial environments with transient coupling. |
| Low quiescent current | 2 µA typical ICC enables use in power-sensitive subsystems without compromising speed. |
Applications
| Industrial PLC I/O Expansion | Digital Test Equipment Signal Routing |
|---|---|
Use Scenario: Consolidating multiple sensor inputs (e.g., thermocouple, pressure, flow) onto a shared microcontroller ADC channel using time-division multiplexing. IC Role / Device Role / Timing Role: Data selector routing analog front-end outputs to a single ADC input under microcontroller GPIO control. Use Value: Reduces PCB trace count and MCU pin usage while maintaining deterministic 4.1 ns channel switching latency. | Use Scenario: Switching between calibration reference signals and DUT outputs during automated test sequences in benchtop ATE systems. IC Role / Device Role / Timing Role: High-fidelity signal path selector enabling precise timing alignment between stimulus and measurement paths. Use Value: Delivers sub-10 ns propagation delay consistency across all four channels, preserving signal integrity at 50 MHz test clock rates. |
| Legacy System Bus Interface | Embedded Control Logic Reduction |
Use Scenario: Interfacing newer 5 V microcontrollers with older peripheral buses (e.g., ISA-style address/data multiplexing) requiring dynamic signal reconfiguration. IC Role / Device Role / Timing Role: Address/data line selector synchronizing CPU read/write cycles with peripheral register access windows. Use Value: TTL-compatible inputs eliminate level translators; strobe-controlled disable prevents bus contention during idle states. | Use Scenario: Replacing discrete logic gates (e.g., AND/OR/NOT combinations) in motor control sequencers to reduce component count and board area. IC Role / Device Role / Timing Role: Configurable data path generator implementing state-dependent output patterns via A/B and G control. Use Value: Integrates four 2:1 functions in one PDIP package-cutting bill-of-materials by 75% versus discrete solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT157DR | SOIC-16 package (5.0 mm × 6.4 mm); RθJA = 67 °C/W vs. PDIP's 67 °C/W (same thermal resistance); identical electrical specs. | Suitable for surface-mount production; requires reflow profile compliance; no through-hole mounting. | Select DR for automated assembly; choose N for prototyping, socket-based testing, or legacy through-hole designs. |
| SN74LVC157A | Lower VCC range (1.65–3.6 V); higher speed (tPD = 3.3 ns @ 3.3 V); CMOS-only inputs (VIH = 2.0 V min at VCC = 3.3 V). | Designed for mixed-voltage 3.3 V systems; not interoperable with 5 V TTL sources without level translation. | Choose LVC157A only when migrating to 3.3 V logic; retain SN74AHCT157N for 5 V or mixed 5 V/TTL environments. |
Compared with SN74AHCT157DR and SN74LVC157A, the SN74AHCT157N uniquely combines 5 V operation, TTL input compatibility, and through-hole PDIP packaging-making it irreplaceable for legacy 5 V system upgrades, lab validation, and hand-soldered development where mechanical robustness and socket reuse matter.
Availability
SN74AHCT157N is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, digital test equipment signal routing, and legacy system bus interface applications requiring stable component supply, long-term obsolescence management, and full traceability.
Supply support for SN74AHCT157N 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 ICs, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74AHCT157N belongs to TI's industry-standard 74AHCT logic family, designed specifically for 5 V systems requiring TTL-compatible inputs, high noise immunity, and drop-in replacement capability for legacy 74LS devices.
FAQ
What is the maximum operating temperature for SN74AHCT157N?
The SN74AHCT157N is rated for operation from –40°C to +85°C ambient temperature. This industrial-grade range is confirmed in Section 4.2 of the official datasheet (SCLS347L, April 2024 revision) and applies to all active SN74AHCT157N units supplied in PDIP packaging. Thermal performance remains stable within this range without derating, supported by measured RθJA = 67 °C/W.
Does SN74AHCT157N require external pull-up or pull-down resistors on unused inputs?
Yes - all unused inputs of the SN74AHCT157N must be held at a defined logic level (VCC or GND) to prevent floating states that cause increased ICC, erratic outputs, or ESD susceptibility. This requirement is explicitly stated in Section 4.2 of the datasheet and reinforced in Application Note SCBA004. Leaving inputs unconnected violates recommended operating conditions and may compromise device reliability.
Can SN74AHCT157N operate reliably at 4.5 V supply voltage?
Yes - the SN74AHCT157N is fully specified and guaranteed to meet all electrical characteristics (including tPD, VOH, VOL, and II) at VCC = 4.5 V, as defined in the Recommended Operating Conditions table (Section 4.2). Its minimum VCC rating is 4.5 V, making it suitable for applications with marginal 5 V rails or brown-out tolerant designs.
Is SN74AHCT157N pin-compatible with SN74LS157?
Yes - the SN74AHCT157N maintains identical pinout, function table, and DC/AC electrical behavior as the legacy SN74LS157, enabling direct replacement in existing designs. Key compatibility points include matching A/B, G, 1A–4A, 1B–4B, 1Y–4Y, VCC, and GND assignments; same truth table; and TTL-compatible input thresholds. No PCB changes are required.
What is the purpose of the strobe (G) input on SN74AHCT157N?
The strobe (G) input on SN74AHCT157N is an active-low global enable that forces all four Y outputs low when asserted high - independent of A/B or data inputs. This feature enables synchronized disabling of all multiplexer outputs to prevent bus contention, isolate signal paths during reset, or implement priority-based arbitration in multi-source systems.
SN74AHCT157N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- 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:
- 8mA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74AHCT157N FAQ
1.How can I place an order for SN74AHCT157N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT157N 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 SN74AHCT157N reliable?
The price and inventory of SN74AHCT157N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT157N is usually 5 days.
3.What payment methods are accepted for SN74AHCT157N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT157N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT157N?
SN74AHCT157N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT157N 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 SN74AHCT157N?
For technical support, including SN74AHCT157N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT157N requirements.
6.How does Aetrix verify that SN74AHCT157N is sourced from the original manufacturer or authorized distributors?
All SN74AHCT157N 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 SN74AHCT157N meets industry standards.
7.What is the process for return or replacement of SN74AHCT157N?
All SN74AHCT157N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT157N, 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 SN74AHCT157N part is unused and in its original packaging.
Return procedure for SN74AHCT157N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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