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Texas Instruments SN74AHCT157DR
- Part No.:
- SN74AHCT157DR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHCT157DR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,991
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Product details
Overview
SN74AHCT157DR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer IC designed for 4.5V–5.5V operation, featuring TTL-voltage-compatible inputs, active-low strobe (G) control, and true (non-inverted) outputs. It routes one of two 4-bit input words to four outputs based on a common select line, enabling compact data path routing in digital logic systems such as address/data bus switching and signal routing in microcontroller peripherals.
For engineers reviewing the SN74AHCT157DR datasheet, SN74AHCT157DR pinout, SN74AHCT157DR application, or SN74AHCT157DR equivalent, this device serves as a high-speed, low-power CMOS multiplexer with verified 7.5 ns typical propagation delay (CL = 15 pF), ±8 mA output drive, and latch-up immunity exceeding 250 mA per JESD17 - critical for industrial control, test equipment, and legacy 5V system upgrades.
Technical Context
The SN74AHCT157DR implements four independent 2:1 multiplexers sharing a single active-low strobe (G) input: when G is high, all Y outputs are forced low; when G is low, each Yn selects between An and Bn based on the A/B select line. Its positive-logic function table defines deterministic output behavior across all input combinations, supporting synchronous data selection without internal latching.
Designed for 5V TTL compatibility, it accepts VIH ≥ 2 V and VIL ≤ 0.8 V while delivering VOH ≥ 3.8 V at IOH = –8 mA and VOL ≤ 0.44 V at IOL = 8 mA - ensuring robust noise margins and interoperability with legacy 5V logic families including LS-TTL and standard TTL.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - supports stable operation across industrial-grade 5V supply tolerances. |
| Propagation Delay (tPLH/tPHL) | 7.5 ns max (CL = 15 pF) - enables reliable timing in 100+ MHz data-path control applications. |
| Output Drive | ±8 mA - sufficient to directly drive multiple 74-series TTL inputs or small capacitive loads without buffering. |
| Input Compatibility | TTL-voltage compatible (VIH ≥ 2 V, VIL ≤ 0.8 V) - eliminates level-shifting when interfacing with legacy 5V microcontrollers and peripheral ICs. |
| Quiescent ICC | 20 μA max at VCC = 5.5 V - ensures minimal static power consumption in always-on logic subsystems. |
| Latch-up Immunity | >250 mA per JESD17 - provides robust protection against transient current faults in noisy industrial environments. |
Pinout & Package
SN74AHCT157DR uses a 16-pin SOIC (D) package measuring 6.2 mm × 10.3 mm (body), with 1.27 mm pitch leads and RoHS-compliant NiPdAu lead finish. The package is rated MSL Level-1 (unlimited floor life) and supports standard reflow profiles up to 260°C peak.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A/B) | Common select input | Determines source (A or B) for all four channels; referenced to G for full enable/disable control. |
| 2–3, 5–6, 10–11, 13–14 (1A–1B, 2A–2B, 3A–3B, 4A–4B) | Data inputs | Eight total inputs grouped into four pairs; each pair feeds one multiplexer channel. |
| 4, 7, 9, 12 (1Y–4Y) | True outputs | Four buffered, non-inverted outputs - no inversion or delay penalty relative to selected input. |
| 8 (GND) | Power reference | Primary ground return for logic and output stages; must be low-impedance for noise immunity. |
| 15 (G) | Strobe enable | Active-low global enable: forces all Y outputs low when high; required for synchronized channel gating. |
| 16 (VCC) | Supply rail | Single 4.5–5.5 V supply powers all logic and output drivers; bypass capacitor mandatory near pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard 5V TTL thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) without external biasing or level shifters. |
| Common strobe control | Single G input disables all outputs simultaneously - simplifies synchronization in multi-channel data routing. |
| True (non-inverting) outputs | Preserves input logic polarity - avoids added inversion logic or timing skew in critical paths. |
| Low quiescent current | ICC ≤ 20 μA at 5.5 V - reduces standby power in battery-backed or energy-sensitive subsystems. |
Applications
| Industrial PLC I/O Expansion | Legacy Microcontroller Bus Switching |
|---|---|
Use Scenario: Routing sensor data from dual analog front-ends to a single ADC channel in programmable logic controllers. IC Role / Device Role / Timing Role: SN74AHCT157DR acts as a hardware-selectable 4-bit data switch, controlled by PLC firmware via GPIO-driven A/B and G lines. Use Value: Enables cost-effective doubling of analog input channels without adding ADCs or FPGA resources - maintains deterministic 7.5 ns switching latency. | Use Scenario: Selecting between two memory-mapped peripheral registers (e.g., UART vs SPI control) on an 8051-based board. IC Role / Device Role / Timing Role: SN74AHCT157DR functions as a decode-assist multiplexer, reducing address decoder gate count while preserving 5V bus timing integrity. Use Value: Eliminates need for discrete NAND/AND logic; supports clean 5V-level transitions with 0.44 V VOL at full 8 mA load - prevents false reads during bus contention. |
| Test Equipment Signal Routing | Automotive Body Control Module Logic |
Use Scenario: Dynamically assigning DUT signals to measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: SN74AHCT157DR serves as a reconfigurable 4-bit signal path selector, driven by test sequencer GPIOs with precise strobe timing. Use Value: Provides sub-10 ns channel switching repeatability - critical for jitter-sensitive parametric testing of high-speed digital interfaces. | Use Scenario: Consolidating status inputs from redundant door lock sensors into a single MCU input port in automotive BCM designs. IC Role / Device Role / Timing Role: SN74AHCT157DR operates as a fail-safe input selector, using G to isolate faulty sensor paths under diagnostic control. Use Value: Delivers JESD17-certified latch-up immunity (>250 mA) - withstands automotive load-dump transients without functional interruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-channel 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT157PW | TSSOP-16 package (5 mm × 6.4 mm body); higher RθJA (135.9 °C/W) than SOIC; identical electrical specs. | Better PCB space efficiency but reduced thermal margin in high-density layouts. | Choose SN74AHCT157PW only when board area is constrained and ambient temperature remains ≤ 60°C. |
| SN74LVC157APWR | 3.3V-only operation (1.65–3.6V); lower VOL (0.55 V @ 24 mA); not TTL-compatible. | Requires level-shifting for 5V systems; unsuitable for direct replacement in legacy 5V designs. | Select SN74LVC157APWR only for new 3.3V-only designs where power efficiency and smaller footprint outweigh voltage compatibility needs. |
Compared with SN74AHCT157PW and SN74LVC157APWR, the SN74AHCT157DR uniquely balances 5V TTL compatibility, SOIC manufacturability, and proven industrial thermal performance - making it the default choice for retrofitting or maintaining existing 5V logic systems without redesign risk.
Availability
SN74AHCT157DR is available at Aetrix Electronics and suitable for industrial automation, test equipment, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.
Supply support for SN74AHCT157DR 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 solutions, with over 90 years of innovation in high-reliability electronic components.
The SN74AHCT157DR belongs to TI's industry-standard 74AHCT logic family, engineered for seamless 5V TTL interoperability, low power consumption, and robust operation in industrial and automotive environments.
FAQ
What is the maximum operating temperature range for the SN74AHCT157DR?
The SN74AHCT157DR is rated for operation from –40°C to +85°C, meeting industrial temperature requirements. This range is validated per TI's recommended operating conditions and supported by thermal metrics including RθJA = 67°C/W for the SOIC (D) package. The SN74AHCT157DR maintains full electrical performance across this span, including guaranteed 7.5 ns max propagation delay and ±8 mA output drive.
Does the SN74AHCT157DR require external pull-up or pull-down resistors on unused inputs?
Yes - all unused inputs of the SN74AHCT157DR must be tied to VCC or GND to prevent floating states that cause undefined outputs and increased ICC. TI explicitly requires this per Section 4.2 of the datasheet. Leaving inputs unconnected risks oscillation, excessive current draw, and potential latch-up. The SN74AHCT157DR has no internal termination, so external biasing is mandatory for reliable operation.
Can the SN74AHCT157DR operate reliably at 4.5V supply voltage?
Yes - the SN74AHCT157DR is fully specified down to 4.5V VCC, with guaranteed VOH ≥ 3.8 V at IOH = –8 mA and VOL ≤ 0.44 V at IOL = 8 mA. Its switching characteristics (e.g., 7.5 ns max tPLH/tPHL) and noise margins remain valid across the entire 4.5–5.5V range. The SN74AHCT157DR delivers consistent performance at 4.5V, making it suitable for brown-out tolerant systems and 5V rails with tight regulation.
Is the SN74AHCT157DR pin-compatible with older 74LS157 devices?
No - while the SN74AHCT157DR matches the 74LS157's logic function and pinout (16-pin SOIC), it is not electrically pin-compatible due to differences in input thresholds and output drive. The SN74AHCT157DR accepts TTL-compatible inputs (VIH ≥ 2 V) but drives stronger outputs (±8 mA vs LS's ±8 mA sink only) and exhibits faster propagation. Direct substitution may work in some cases, but timing and loading must be re-verified - the SN74AHCT157DR is not a drop-in replacement.
What is the purpose of the G (strobe) pin on the SN74AHCT157DR?
The G pin on the SN74AHCT157DR is an active-low global enable that overrides all channel selections: when G = HIGH, all four Y outputs are forced LOW regardless of A/B or data inputs; when G = LOW, normal 2:1 multiplexing resumes. This allows synchronized disabling of all outputs - essential for bus arbitration, glitch-free state transitions, and power-gated logic sections. The SN74AHCT157DR uses G to eliminate output contention during mode changes.
SN74AHCT157DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74AHCT157DR FAQ
1.How can I place an order for SN74AHCT157DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT157DR 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 SN74AHCT157DR reliable?
The price and inventory of SN74AHCT157DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT157DR is usually 5 days.
3.What payment methods are accepted for SN74AHCT157DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT157DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT157DR?
SN74AHCT157DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT157DR 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 SN74AHCT157DR?
For technical support, including SN74AHCT157DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT157DR requirements.
6.How does Aetrix verify that SN74AHCT157DR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT157DR 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 SN74AHCT157DR meets industry standards.
7.What is the process for return or replacement of SN74AHCT157DR?
All SN74AHCT157DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT157DR, 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 SN74AHCT157DR part is unused and in its original packaging.
Return procedure for SN74AHCT157DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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