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Texas Instruments SN74AS253AN
- Part No.:
- SN74AS253AN
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AS253AN.pdf
- Description:
- IC MULTIPLEXER 2 X 4:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:26,760
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Product details
Overview
SN74AS253AN 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 data routing in TTL-compatible logic subsystems.
For engineers reviewing the SN74AS253AN datasheet, SN74AS253AN pinout, SN74AS253AN application, or SN74AS253AN equivalent, key selection criteria include its 16-pin PDIP (N) package, 48 mA low-level output drive, 13.5 ns max propagation delay (A/B to Y), independent 3-state control per output, and compatibility with standard TTL logic levels.
Technical Context
The SN74AS253AN implements two independent 4:1 multiplexer sections sharing select lines A and B, each with dedicated output-enable (1OE, 2OE) and 3-state output (1Y, 2Y). Its internal architecture includes binary decoding logic driving AND-OR gates, with inverters and drivers ensuring full TTL signal integrity.
Each section selects one of four data inputs (C0–C3) based on A/B states, while OE controls high-impedance output state. The device supports bus interfacing by enabling only one output at a time, minimizing contention - critical for shared-data-path applications like address/data multiplexing and I/O expansion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL power rails and noise margin stability. |
| Output Drive (IOL) | 48 mA - enables direct driving of multiple TTL loads or termination-resistor networks without buffers. |
| Propagation Delay (tPHL/tPLH) | ≤13.5 ns (A/B → Y) - supports high-speed data routing in ≤74 MHz synchronous logic domains. |
| 3-State Enable Time (tPHZ) | ≤6 ns - allows rapid bus arbitration and fast output release for time-critical multiplexed interfaces. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded control, instrumentation, and industrial logic boards. |
| Input Logic Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL input sensitivity, eliminating level-shifting in mixed-logic systems. |
| Quiescent Current (ICC) | 29 mA (outputs high) - predictable power budgeting for multi-device logic arrays with known fan-out. |
Pinout & Package
SN74AS253AN uses a 16-pin plastic dual in-line package (PDIP-N), 300-mil width, with standard through-hole mounting and 0.1-inch pin spacing. Pin 1 is located at the top-left corner (notch-side left), with pin numbering counterclockwise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1C0 | Data input 0 for first multiplexer section - connects to source signal routed when A=0, B=0. |
| 2 | 1C1 | Data input 1 for first section - selected when A=1, B=0. |
| 3 | 1C2 | Data input 2 for first section - selected when A=0, B=1. |
| 4 | 1C3 | Data input 3 for first section - selected when A=1, B=1. |
| 5 | 1Y | 3-state output of first section - drives bus line only when 1OE = L; high-Z otherwise. |
| 6 | 1OE | Output-enable for first section - active-low control; disables 1Y to high impedance when high. |
| 7 | GND | Ground reference - common return path for all logic and output currents. |
| 8 | VCC | Positive supply - powers internal logic and output drivers; requires local 0.1 µF bypass capacitor. |
| 9 | 2Y | 3-state output of second section - independently controllable via 2OE; shares A/B select lines. |
| 10 | 2C0 | Data input 0 for second section - identical function to 1C0 but isolated signal path. |
| 11 | 2C1 | Data input 1 for second section - enables dual-channel multiplexing without external gating. |
| 12 | 2C2 | Data input 2 for second section - supports mirrored or independent data stream selection. |
| 13 | 2C3 | Data input 3 for second section - completes full 4-input capability for second channel. |
| 14 | 2OE | Output-enable for second section - decouples bus loading between sections during partial enable. |
| 15 | B | Common select input (LSB) - shared by both sections; determines bit-0 of 2-bit address. |
| 16 | A | Common select input (MSB) - shared by both sections; determines bit-1 of 2-bit address. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4:1 multiplexers | Enables simultaneous routing of two separate 4-source data streams using shared address lines A/B - reduces PCB routing and control logic overhead. |
| Individual 3-state outputs with dedicated OE | Allows selective bus connection per section - prevents contention when multiple SN74AS253AN devices share a common data bus. |
| 48 mA sink capability (IOL) | Drives up to 10 standard TTL loads directly - eliminates need for external buffer stages in legacy system upgrades. |
| 13.5 ns max A/B-to-Y propagation | Supports clock rates up to 74 MHz in critical timing paths - suitable for high-speed address/data switching in microprocessor peripherals. |
| TTL-compatible input thresholds | Accepts standard 0.8 V / 2.0 V logic levels - interoperates seamlessly with 74LS, 74ALS, and other bipolar TTL families without interface circuitry. |
Applications
| Microprocessor Address/Data Multiplexing | Industrial PLC I/O Expansion |
|---|---|
|
Use Scenario: Demultiplexing address and data lines on an 8-bit microprocessor bus to reduce pin count on peripheral ICs. IC Role / Device Role / Timing Role: SN74AS253AN acts as a bidirectional data path selector, routing either address or data signals onto shared bus lines under CPU control. Use Value: Reduces required PCB traces and connector pins by 50% compared to non-multiplexed designs, while maintaining full 8-bit throughput via time-division. |
Use Scenario: Consolidating discrete sensor inputs (e.g., limit switches, temperature sensors) into a single serial scan bus for programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: SN74AS253AN serves as a scan-chain multiplexer, sequentially presenting 4 sensor channels per section to a central ADC or monitoring logic block. Use Value: Enables 8-channel analog/digital input aggregation per device with deterministic 13.5 ns switching - improves scan cycle time and reduces component count per I/O module. |
| Legacy System Bus Arbitration | Test Equipment Signal Routing |
|
Use Scenario: Managing shared memory or peripheral access across multiple DMA controllers in a vintage computer architecture. IC Role / Device Role / Timing Role: SN74AS253AN functions as a priority-based bus gate, enabling one controller's data path while tri-stating others' outputs. Use Value: Prevents bus contention with sub-14 ns enable/disable transitions - ensures reliable handshaking in asynchronous DMA cycles without external arbitration logic. |
Use Scenario: Configuring flexible signal paths in automated test equipment (ATE) to route stimulus or measurement signals between DUT ports and instruments. IC Role / Device Role / Timing Role: SN74AS253AN provides reconfigurable 4:1 signal selection per channel, controlled by test sequencer GPIOs. Use Value: Delivers <14 ns path delay consistency across all 8 inputs - maintains signal fidelity for sub-100 MHz analog/digital test waveforms without skew-induced jitter. |
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 |
|---|---|---|---|
| SN74ALS253N | Lower drive (24 mA IOL), slower speed (21 ns max tPHL), higher ICC (14 mA vs. 29 mA) | Optimized for lower-power, cost-sensitive TTL systems where speed >40 MHz is not required | Choose SN74ALS253N if board-level power budget is constrained and propagation delay tolerance ≥21 ns is acceptable. |
| SN74F253N | Fast TTL variant: 10 ns max tPHL, 20 mA IOL, no 3-state outputs (totem-pole only) | Requires external pull-up/pull-down or bus buffers for shared-bus use; unsuitable for direct bus-driving | Choose SN74F253N only for point-to-point routing where 3-state control is unnecessary and speed is critical. |
Compared with SN74ALS253N and SN74F253N, the SN74AS253AN delivers the highest output drive and fastest 3-state switching among pin-compatible dual 4:1 multiplexers - making it optimal for bus-loaded, high-speed legacy TTL designs requiring robust signal integrity and minimal external components.
Availability
SN74AS253AN is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, and retro-computing hardware requiring stable component supply, long-lifecycle support, and verified through-hole assembly compatibility.
Supply support for SN74AS253AN 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 SN74AS253AN belongs to TI's advanced Schottky (AS) logic family, engineered for high-speed, high-drive TTL-compatible operation in mission-critical digital subsystems where reliability and timing precision are essential.
FAQ
What is the maximum operating frequency supported by the SN74AS253AN?
The SN74AS253AN does not specify a maximum clock frequency directly, but its 13.5 ns maximum propagation delay (A/B to Y) and 7 ns maximum 3-state disable time (tPLZ) support reliable operation in synchronous systems with clock periods ≥20 ns - corresponding to a practical upper limit of approximately 50 MHz for worst-case combinational paths. For precise timing analysis, designers must account for setup/hold times and load capacitance per the SDAS216A datasheet.
Can the SN74AS253AN be used with 3.3 V logic systems?
No - the SN74AS253AN is strictly a 5 V TTL device requiring VCC = 4.5–5.5 V and exhibiting TTL input thresholds (VIH = 2.0 V, VIL = 0.8 V). It lacks 3.3 V tolerance: applying 3.3 V to VCC violates minimum supply specification, and 3.3 V logic-high signals may fail to meet VIH margin. Interfacing with 3.3 V systems requires level translation or a modern 3.3 V-compatible multiplexer such as the SN74LVC253A.
Does the SN74AS253AN support hot-swap or live-insertion?
No - the SN74AS253AN has no built-in hot-swap protection. Its absolute maximum ratings do not cover powered insertion, and the lack of power-on reset or Ioff (power-off isolation) means applying VCC while inputs are driven can cause latch-up or excessive current draw. For hot-swap applications, use purpose-designed hot-swap controllers or bus buffers with Ioff and power sequencing support.
How does the SN74AS253AN differ from the SN74AS153 in functionality?
The SN74AS253AN is a 3-state version of the SN74AS153, adding independent output-enable (1OE/2OE) inputs per section and high-impedance output capability. While both perform dual 4:1 multiplexing with shared A/B selects, only the SN74AS253AN supports bus-oriented applications - the SN74AS153 has standard totem-pole outputs and cannot be safely wired in parallel without external isolation.
Is the SN74AS253AN RoHS compliant?
Yes - the SN74AS253AN (orderable part SN74AS253AN) is RoHS compliant, as confirmed by Texas Instruments' packaging addendum. It features NiPdAu (NIPDAU) lead finish and meets JEDEC Level-1 moisture sensitivity requirements for standard reflow profiles. Full compliance documentation is available in TI's official materials database under orderable number SN74AS253AN.
SN74AS253AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74AS253AN FAQ
1.How can I place an order for SN74AS253AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS253AN 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 SN74AS253AN reliable?
The price and inventory of SN74AS253AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS253AN is usually 5 days.
3.What payment methods are accepted for SN74AS253AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS253AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS253AN?
SN74AS253AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS253AN 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 SN74AS253AN?
For technical support, including SN74AS253AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS253AN requirements.
6.How does Aetrix verify that SN74AS253AN is sourced from the original manufacturer or authorized distributors?
All SN74AS253AN 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 SN74AS253AN meets industry standards.
7.What is the process for return or replacement of SN74AS253AN?
All SN74AS253AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS253AN, 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 SN74AS253AN part is unused and in its original packaging.
Return procedure for SN74AS253AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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