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Texas Instruments SN74ALS253NSR
- Part No.:
- SN74ALS253NSR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS253NSR.pdf
- Description:
- IC MULTIPLEXER 2 X 4:1 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,057
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Product details
Overview
SN74ALS253NSR from Texas Instruments is a dual 4-line to 1-line data selector/multiplexer with independent 3-state outputs, designed for bus-organized digital systems. It features two independent 4-input sections (1C0–1C3 and 2C0–2C3), common select inputs (A/B), individual output-enable (1OE/2OE), and operates at 4.5–5.5 V over 0°C to 70°C. Used in parallel-to-serial conversion and address/data multiplexing in legacy industrial controllers and test equipment.
For engineers reviewing the SN74ALS253NSR datasheet, SN74ALS253NSR pinout, SN74ALS253NSR application, or SN74ALS253NSR equivalent, key selection criteria include its dual-section 3-state architecture, 16-pin PDIP package, guaranteed propagation delays ≤21 ns (tPLH/tPHL), ±24 mA output drive capability, and compatibility with ALS logic family voltage thresholds.
Technical Context
The SN74ALS253NSR implements two independent 4:1 multiplexer sections sharing select lines A and B, each with dedicated output-enable (1OE, 2OE) controlling high-impedance state. Its internal AND-OR-inverter decoding structure ensures full binary selection without external gating.
Each section drives a single 3-state output (1Y, 2Y) capable of sourcing −2.6 mA or sinking 24 mA at VCC = 4.5 V, meeting ALS-level interface requirements. Propagation delay from data or select inputs to output is specified down to 2 ns (tPLH on data), with enable/disable times as low as 2 ns (tPHZ).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Low-Power Schottky (ALS), compatible with TTL input/output levels |
| Supply Voltage Range | 4.5 V to 5.5 V - supports standard 5 V digital rails with margin for ripple |
| Output Drive Capability | ±24 mA sink/source - sufficient to directly drive multiple TTL loads or small buses |
| Propagation Delay (max) | 21 ns (tPLH/tPHL, data→Y) - enables reliable operation up to ~25 MHz in non-critical timing paths |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and instrumentation applications |
| 3-State Enable Time | 10 ns (tPHZ, OE→Y active) - allows fast bus arbitration and dynamic signal routing |
| Input Voltage Thresholds | VIL = 0.8 V, VIH = 2.0 V - ensures noise immunity and interoperability with standard TTL outputs |
Pinout & Package
SN74ALS253NSR is supplied in a 16-pin plastic dual in-line package (PDIP-N), 300-mil width, with standard through-hole mounting and 0.1-inch pin pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1OE | Active-low output-enable for first multiplexer section (1Y) |
| 2 | 1C0 | Data input 0 for first section |
| 3 | 1C1 | Data input 1 for first section |
| 4 | 1C2 | Data input 2 for first section |
| 5 | 1C3 | Data input 3 for first section |
| 6 | 1Y | 3-state output for first section |
| 7 | GND | Ground reference for power and logic |
| 8 | 2C0 | Data input 0 for second multiplexer section |
| 9 | 2Y | 3-state output for second section |
| 10 | 2C1 | Data input 1 for second section |
| 11 | 2C2 | Data input 2 for second section |
| 12 | 2C3 | Data input 3 for second section |
| 13 | 2OE | Active-low output-enable for second section (2Y) |
| 14 | VCC | +5 V supply rail |
| 15 | B | Common select bit (LSB) for both sections |
| 16 | A | Common select bit (MSB) for both sections |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4:1 multiplexers | Enables simultaneous routing of two separate 4-input data streams using shared A/B select lines |
| Individual 3-state output enables | Allows per-section bus contention control - one section can drive while the other is tri-stated |
| ALS-compatible speed-power product | 21 ns max propagation delay with 12 mA typical ICC - optimized for low-noise, medium-speed digital systems |
| Full binary decoding logic | Internal inverters and AND-OR gates eliminate need for external decode logic when selecting among four inputs |
| TTL-compatible input thresholds | VIL ≤ 0.8 V and VIH ≥ 2.0 V ensure robust interfacing with legacy 74LS/74F and microcontroller GPIO |
Applications
| Industrial PLC I/O Expansion | Legacy Test Equipment Signal Routing |
|---|---|
|
Use Scenario: Expanding discrete input channels in programmable logic controllers by multiplexing sensor signals onto shared data buses. IC Role / Device Role / Timing Role: Dual 4:1 multiplexer enabling time-division sampling of eight analog/digital inputs via two independent control paths. Use Value: Reduces PCB trace count and microcontroller pin usage while maintaining deterministic access latency under 25 ns per channel. |
Use Scenario: Dynamic reconfiguration of stimulus/sense paths in automated test fixtures for mixed-signal board validation. IC Role / Device Role / Timing Role: Bus-isolated signal switch providing glitch-free path selection during test sequence transitions. Use Value: Prevents bus contention during reconfiguration via independent OE controls, eliminating need for external bus buffers. |
| Microcontroller Address/Data Multiplexing | EPROM Memory Banking Control |
|
Use Scenario: Sharing address/data bus lines between peripherals in 8-bit microcontroller systems with limited I/O resources. IC Role / Device Role / Timing Role: Parallel-to-serial converter translating 4-bit peripheral ID into selected data path under A/B select control. Use Value: Enables single-port expansion of up to four memory-mapped peripherals without adding address latch logic. |
Use Scenario: Selecting among multiple EPROM banks in vintage computer or embedded firmware upgrade systems. IC Role / Device Role / Timing Role: Dual-section selector routing chip-enable signals to one of four EPROM devices based on upper address bits. Use Value: Supports 64 KB address space partitioning with hardware-level bank switching and no software overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 4:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS253AD | Faster propagation (7.5 ns max), higher drive (±48 mA), AS-family AC characteristics | Requires tighter layout for signal integrity; not drop-in due to different VIH/VIL thresholds | Preferred for high-speed bus arbitration where SN74ALS253NSR timing margins are insufficient |
| SN74LS253N | Lower drive (±8 mA), slower (35 ns max), LS-family power consumption (~19 mA ICC) | Compatible pinout and voltage thresholds; suitable for low-power, non-timing-critical upgrades | Valid functional replacement where speed and drive strength are secondary to cost and availability |
Compared with SN74ALS253NSR, SN74AS253AD delivers higher performance at the cost of increased power and stricter layout rules, while SN74LS253N offers lower power and broader legacy compatibility but sacrifices speed and drive strength - making SN74ALS253NSR the balanced choice for commercial-grade systems requiring reliability, moderate speed, and proven ALS interoperability.
Availability
SN74ALS253NSR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy test equipment signal routing, microcontroller address/data multiplexing, EPROM memory banking control, and bus-organized digital system design requiring stable component supply across long-lifecycle programs.
Supply support for SN74ALS253NSR 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 solutions for industrial, automotive, and communications markets.
The SN74ALS253NSR belongs to TI's legacy Advanced Low-Power Schottky (ALS) logic family, engineered for reliable, medium-speed digital interfacing in commercial-temperature environments with emphasis on noise immunity and bus-driving capability.
FAQ
What is the maximum clock rate supported by SN74ALS253NSR in multiplexer operation?
The SN74ALS253NSR does not operate on a clock signal - it is a combinational logic device. Its maximum usable data rate depends on propagation delay and system setup/hold timing. With tPLH/tPHL ≤ 21 ns and tPZH/tPHZ ≤ 14 ns, it supports reliable operation in static bus-multiplexing applications up to approximately 25 MHz when interfaced with compatible drivers and loads. The SN74ALS253NSR requires no clock input and responds asynchronously to select and data changes.
Does SN74ALS253NSR support hot-swapping or live insertion into an active bus?
No, SN74ALS253NSR is not designed for hot-swap operation. Its absolute maximum ratings specify no voltage stress during insertion, and the device lacks bus-fault protection, current-limiting circuitry, or power-up sequencing control. Inserting SN74ALS253NSR into a powered bus risks latch-up or damage due to uncontrolled voltage transients on VCC, GND, or I/O pins. Always power down the system before replacing SN74ALS253NSR.
Can SN74ALS253NSR be used to replace SN74LS253 in existing designs?
Yes, SN74ALS253NSR is a direct pin-compatible and functionally equivalent upgrade for SN74LS253 in most cases. Both share identical pinout, logic function, and TTL-compatible voltage thresholds. SN74ALS253NSR improves on LS performance with faster propagation (21 ns vs. 35 ns), higher output drive (24 mA vs. 8 mA), and lower power dissipation (12 mA ICC vs. 19 mA). Verify timing margins and load capacitance in high-speed layouts before substitution.
What is the purpose of the NC pins in SN74ALS253NSR's PDIP package?
SN74ALS253NSR has no NC (No Connect) pins in its 16-pin PDIP (N) package. All 16 pins are assigned: pins 1–16 correspond to 1OE, 1C0–1C3, 1Y, GND, 2C0–2C3, 2Y, 2OE, VCC, B, and A respectively. NC pins appear only in ceramic packages (e.g., FK, J) due to die pad layout constraints - the PDIP version fully utilizes all leads for signal, power, and ground connections.
Is SN74ALS253NSR RoHS compliant?
Yes, SN74ALS253NSR (orderable part SN74ALS253N and SN74ALS253N.A) is RoHS compliant, featuring NiPdAu (NIPDAU) lead finish and meeting EU Directive 2011/65/EU requirements. TI's packaging addendum confirms "Yes" for RoHS status, and the device carries no lead or hazardous substance exemptions. Full compliance documentation is available in TI's official materials declaration reports.
SN74ALS253NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 2 x 4:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
SN74ALS253NSR FAQ
1.How can I place an order for SN74ALS253NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS253NSR 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 SN74ALS253NSR reliable?
The price and inventory of SN74ALS253NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS253NSR is usually 5 days.
3.What payment methods are accepted for SN74ALS253NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS253NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS253NSR?
SN74ALS253NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS253NSR 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 SN74ALS253NSR?
For technical support, including SN74ALS253NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS253NSR requirements.
6.How does Aetrix verify that SN74ALS253NSR is sourced from the original manufacturer or authorized distributors?
All SN74ALS253NSR 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 SN74ALS253NSR meets industry standards.
7.What is the process for return or replacement of SN74ALS253NSR?
All SN74ALS253NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS253NSR, 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 SN74ALS253NSR part is unused and in its original packaging.
Return procedure for SN74ALS253NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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