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Texas Instruments SN74LVC257AD
- Part No.:
- SN74LVC257AD
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LVC257AD.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
SN74LVC257AD from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state outputs, designed for 1.65V–3.6V VCC operation. It supports mixed-voltage interfacing (inputs tolerate up to 5.5V), delivers 4.6ns max propagation delay at 3.3V, and enables bus-organized signal routing in 4-bit data paths - widely used in I/O expanders and network switch control planes.
For engineers reviewing the SN74LVC257AD datasheet, SN74LVC257AD pinout, SN74LVC257AD application, or SN74LVC257AD equivalent, key selection criteria include its 3-state output enable logic, voltage translation capability across 3.3V/5V domains, low ground bounce (<0.8V), and SOIC-16 package compatibility with industrial PCB layouts.
Technical Context
This device implements four independent 2:1 multiplexers sharing a common active-low output-enable (OE) input and a single select line (A/B). Each channel routes either input A or B to its corresponding Y output based on A/B logic level, while OE controls high-impedance tri-state behavior - critical for shared bus arbitration without contention.
Its CMOS design ensures balanced drive strength (±24mA at 3V), low input/output capacitance (5pF), and latch-up immunity (>250mA per JESD17). The 3.3V-optimized switching performance (tpd ≤4.6ns) and overvoltage-tolerant inputs make it suitable for level-shifting between legacy 5V logic and modern low-voltage microcontrollers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 1.65V to 3.6V - supports single-supply operation across LVC-family voltage rails including 1.8V, 2.5V, and 3.3V systems. |
| Input Voltage Tolerance | Up to 5.5V - enables direct connection to 5V TTL/CMOS outputs without external level shifters. |
| Max Propagation Delay | 4.6ns at VCC = 3.3V - ensures timing compliance in high-speed digital control paths up to ~200MHz toggle rate. |
| Output Drive Strength | ±24mA at VCC = 3V - sufficient to drive standard 50Ω transmission lines or multiple 74LVC inputs without fanout limitation. |
| 3-State Leakage | ±10μA at VCC = 3.6V - minimizes bus leakage current when outputs are disabled, preserving signal integrity on shared data lines. |
| ESD Rating | ±2000V HBM - meets industrial-grade robustness requirements for handling and board assembly environments. |
Pinout & Package
SN74LVC257AD is packaged in a 16-pin SOIC (D package), body size 9.90 mm × 3.90 mm, with standard 1.27 mm pitch. Pin 1 is located at the top-left corner adjacent to the index mark.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B | Multiplexer Data Inputs | Eight bidirectional signal inputs grouped into four 2-input pairs; each pair feeds one multiplexer channel. |
| 1Y, 2Y, 3Y, 4Y | Multiplexer Outputs | Four 3-state outputs - driven only when OE = low; high-impedance when OE = high to prevent bus loading. |
| A/B | Select Control Input | Global 2:1 select line: logic low routes A inputs to Y outputs; logic high routes B inputs to Y outputs. |
| OE | Active-Low Output Enable | Tri-states all Y outputs when high; enables output drivers when low - essential for bus arbitration and hot-swap isolation. |
| VCC | Power Supply | Primary supply rail (1.65–3.6V); must be bypassed with 0.1μF capacitor near pin 16 for noise suppression. |
| GND | Ground Reference | Signal and power return path; connects to system ground plane to maintain reference stability and minimize ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Voltage Translation Capability | Accepts 5V-tolerant inputs while operating from 1.65V–3.6V supply - eliminates need for discrete level shifters in mixed-voltage systems. |
| Low Propagation Delay | 4.6ns max at 3.3V enables use in timing-critical applications such as address/data multiplexing in FPGA I/O banks or microcontroller peripheral expansion. |
| High-Noise Immunity | Typical VOLP < 0.8V and VOHV > 2V at 3.3V - suppresses ground bounce and undershoot that could corrupt adjacent signals in dense PCB layouts. |
| Robust ESD Protection | Exceeds ±2000V HBM and ±1000V CDM - reduces field failure risk during handling, assembly, and end-use in industrial environments. |
| Latch-Up Immunity | >250mA per JESD17 - prevents destructive parasitic SCR activation under transient overvoltage or supply sequencing faults. |
Applications
| Network Switch Control Plane | I/O Expansion for Microcontrollers |
|---|---|
Use Scenario: Routing configuration signals between management CPU and multiple PHY interfaces in Layer 2/L3 switches. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer selecting between primary and backup register sets or clock sources per port group. Use Value: Enables dynamic reconfiguration of link parameters without hardware modification, leveraging 3-state outputs to isolate unused paths. |
Use Scenario: Expanding GPIO count on resource-constrained MCUs (e.g., ARM Cortex-M0+) for sensor arrays or LED drivers. IC Role / Device Role / Timing Role: Multiplexing parallel sensor data streams onto fewer MCU pins while maintaining real-time sampling order via A/B select. Use Value: Reduces required MCU pin count by 4× with deterministic 4.6ns latency - critical for time-synchronized multi-channel acquisition. |
| Test & Measurement Equipment | Cable Modem Termination Systems |
Use Scenario: Signal routing in automated test equipment (ATE) where multiple DUTs share analog/digital stimulus resources. IC Role / Device Role / Timing Role: Selecting between calibration references and live DUT outputs using OE-controlled 3-state isolation. Use Value: Prevents back-driving during test sequence transitions, ensuring measurement accuracy and protecting sensitive front-end circuitry. |
Use Scenario: Managing upstream/downstream channel selection and failover paths in DOCSIS-compliant CMTS hardware. IC Role / Device Role / Timing Role: Multiplexing RF control signals between redundant modulator/demodulator modules under software-defined radio (SDR) control. Use Value: Supports hot-swappable module replacement with zero bus contention due to guaranteed high-Z state during OE assertion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC157AD | Identical functionality and pinout; differs only in output-enable polarity (active-high vs. SN74LVC257AD's active-low OE). | Requires inverted OE control logic; unsuitable where existing firmware assumes active-low enable signaling. | Select SN74LVC157AD only if system-level OE driver is open-drain or actively drives high - otherwise SN74LVC257AD maintains direct logic compatibility. |
| 74LVCH16257MTDX | 16-bit version in TSSOP-48; higher channel count but incompatible pinout and package - not drop-in replaceable. | Used in high-density backplane routing; requires full PCB redesign and layout revision. | Choose only for new designs needing >4 channels; avoid for SN74LVC257AD replacement due to mechanical and electrical incompatibility. |
Compared with SN74LVC157AD and 74LVCH16257MTDX, SN74LVC257AD provides optimal balance of pin-compatible upgrade path, active-low OE alignment with industrial control standards, and SOIC-16 footprint compatibility - making it the preferred choice for cost-sensitive, space-constrained multiplexer implementations.
Availability
SN74LVC257AD is available at Aetrix Electronics and suitable for network switches, I/O expanders, and test & measurement equipment requiring stable component supply across extended production lifecycles.
Supply support for SN74LVC257AD 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 50 years of innovation in high-reliability digital ICs.
The SN74LVC257AD belongs to TI's LVC logic family - engineered for low-voltage operation, mixed-signal interoperability, and robust performance in industrial and communications infrastructure applications.
FAQ
What is the recommended power supply bypassing scheme for SN74LVC257AD?
TI specifies a 0.1μF ceramic capacitor placed as close as possible to the VCC pin (pin 16) and GND (pin 8) of SN74LVC257AD. This minimizes high-frequency noise coupling and stabilizes supply voltage during fast output transitions. For boards with multiple SN74LVC257AD devices, individual capacitors per IC are mandatory - daisy-chaining bypass caps degrades effectiveness and may cause ground bounce exceeding the typical <0.8V spec.
Does SN74LVC257AD support 5V logic inputs while powered from 1.8V?
Yes, SN74LVC257AD explicitly supports 5.5V-tolerant inputs across its full 1.65V–3.6V VCC range, including at 1.8V operation. This allows direct interface with legacy 5V TTL outputs without external level shifters. However, output VOH/VOL levels will conform to the 1.8V supply rail - not 5V - so downstream receivers must be 1.8V-compatible or have appropriate input thresholds.
How does the A/B select input function in SN74LVC257AD?
The A/B input is a global select line controlling all four multiplexer channels simultaneously: when A/B = low, each Y output reflects its corresponding A input (1Y = 1A, 2Y = 2A, etc.); when A/B = high, each Y output reflects its B input (1Y = 1B, 2Y = 2B, etc.). This synchronous 4-channel selection enables coordinated data path switching - essential for applications like dual-bank memory addressing or redundant signal routing.
What happens to SN74LVC257AD outputs when OE is left unconnected?
Leaving OE floating violates TI's absolute maximum ratings and risks undefined output states. SN74LVC257AD OE is active-low; an unconnected OE may float toward VCC, forcing all outputs into high-impedance mode unpredictably. TI mandates tying OE to VCC via a pullup resistor (value determined by driver sink capability) during power-up/down to guarantee known initial state - critical for bus integrity in live systems.
Can SN74LVC257AD be used in automotive applications?
SN74LVC257AD is rated for –40°C to +85°C operation and meets JESD17 latch-up and JESD22 ESD specifications, but it is not AEC-Q100 qualified. While functionally suitable for non-safety-critical automotive subsystems (e.g., infotainment I/O expansion), TI does not warrant its use in safety-related functions (ASIL-B/C) or under hood environments exceeding 85°C ambient. For automotive-grade alternatives, consult TI's specific AEC-Q100-certified logic portfolio.
SN74LVC257AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74LVC257AD FAQ
1.How can I place an order for SN74LVC257AD through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC257AD 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 SN74LVC257AD reliable?
The price and inventory of SN74LVC257AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC257AD is usually 5 days.
3.What payment methods are accepted for SN74LVC257AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC257AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC257AD?
SN74LVC257AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC257AD 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 SN74LVC257AD?
For technical support, including SN74LVC257AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC257AD requirements.
6.How does Aetrix verify that SN74LVC257AD is sourced from the original manufacturer or authorized distributors?
All SN74LVC257AD 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 SN74LVC257AD meets industry standards.
7.What is the process for return or replacement of SN74LVC257AD?
All SN74LVC257AD units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC257AD, 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 SN74LVC257AD part is unused and in its original packaging.
Return procedure for SN74LVC257AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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