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Texas Instruments SN74AS253ADR
- Part No.:
- SN74AS253ADR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS253ADR.pdf
- Description:
- IC MULTIPLEXER 2 X 4:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,065
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Product details
Overview
SN74AS253ADR 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 (C0–C3 per section), common select inputs (A/B), individual output-enable (1OE/2OE) controls, and operates over 0°C to 70°C at 4.5–5.5 V supply. It enables parallel-to-serial conversion in TTL-compatible logic circuits.
For engineers reviewing the SN74AS253ADR datasheet, SN74AS253ADR pinout, SN74AS253ADR application, or SN74AS253ADR equivalent, key selection criteria include its 16-pin SOIC-D 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 SN74AS253ADR 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 (1C0–1C3 or 2C0–2C3) based on A/B states, while OE assertion places the corresponding Y output in high-impedance mode. The device supports bus interfacing by allowing only one output to drive the line while others remain disabled - critical for shared data-path applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL systems and margin against rail droop. |
| Logic Family | AS (Advanced Schottky) - delivers higher speed and lower power than ALS, with 7.5 ns typical tPHL on data inputs. |
| Output Drive | IOL = 48 mA - sufficient to directly drive multiple TTL loads or terminate short PCB traces without buffering. |
| Propagation Delay | tPLH/tPHL ≤ 13.5 ns (A/B to Y) - enables reliable operation in 70 MHz+ clock domains with setup/hold margin. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade industrial and computing equipment environments. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL voltage levels for seamless integration with legacy logic families. |
| 3-State Leakage | IOZL/IOZH ≤ ±50 µA - guarantees minimal bus contention during output disable, preserving signal integrity on shared lines. |
Pinout & Package
SN74AS253ADR is supplied in a 16-pin plastic small-outline integrated circuit (SOIC-D) package, 7.5 mm wide, with 1.27 mm pitch and gull-wing leads. Pin 1 is marked via notch or bevel; device orientation follows JEDEC MS-012 standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1C0 | Data input 0 for first multiplexer section - connects to source signal selected when A=0, B=0. |
| 2 | 1C1 | Data input 1 for first section - active when A=1, B=0. |
| 3 | 1C2 | Data input 2 for first section - active when A=0, B=1. |
| 4 | 1C3 | Data input 3 for first section - active when A=1, B=1. |
| 5 | 1Y | 3-state output for first section - drives bus line only when 1OE = low; high-Z otherwise. |
| 6 | 2C0 | Data input 0 for second multiplexer section - independent channel, same select logic. |
| 7 | 2C1 | Data input 1 for second section - enables dual-channel multiplexing without external gating. |
| 8 | GND | Ground reference - must be low-impedance connection to minimize noise coupling into logic paths. |
| 9 | 2Y | 3-state output for second section - independently controllable via 2OE; supports time-multiplexed dual-bus access. |
| 10 | 2C2 | Data input 2 for second section - expands system I/O flexibility using single-package dual functionality. |
| 11 | 2C3 | Data input 3 for second section - completes full 4-input selection per section. |
| 12 | VCC | +5 V supply - requires local 0.1 µF ceramic decoupling adjacent to pin for transient current stability. |
| 13 | 1OE | Output-enable for first section - active-low control; asserts 1Y only when logic low. |
| 14 | 2OE | Output-enable for second section - independent enable allows staggered or conditional bus access. |
| 15 | A | Common select input A - shared between both sections to reduce control line count and simplify address decoding. |
| 16 | B | Common select input B - paired with A to generate 2-bit binary select code (00–11) for all eight inputs. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4:1 multiplexers | Enables two simultaneous data routing paths (e.g., sensor + memory read) in one IC, reducing board space and interconnect complexity. |
| Individual 3-state outputs with separate OE | Allows precise timing control of bus arbitration - e.g., 1Y active while 2Y disabled prevents contention during multi-source transfers. |
| AS-family speed-performance | Delivers 13.5 ns max propagation delay (A/B → Y) and 7 ns typical, outperforming ALS variants by ~40% for real-time signal switching. |
| TTL-compatible input/output thresholds | Directly interfaces with 74LS, 74F, and microcontroller GPIO without level-shifting, simplifying mixed-logic designs. |
| High-current sink capability (48 mA) | Drives up to 10 standard TTL loads or terminates unterminated stubs in backplane applications without external buffers. |
Applications
| Microprocessor Address/Data Bus Multiplexing | Industrial PLC I/O Expansion |
|---|---|
Use Scenario: Selecting among multiple peripheral address decoders or memory banks in an 8-bit microprocessor system with limited address lines. IC Role / Device Role / Timing Role: SN74AS253ADR acts as a dual-channel address decoder enabling dynamic bank switching; A/B select lines derive from upper address bits, OE signals synchronize with memory enable strobes. Use Value: Reduces need for discrete logic gates or CPLDs, cuts PCB layer count via compact SOIC footprint, and ensures sub-15 ns address settling for 8 MHz CPU operation. | Use Scenario: Routing analog-to-digital converter outputs or sensor data streams to a central controller in modular I/O racks. IC Role / Device Role / Timing Role: SN74AS253ADR serves as a configurable signal router - each section handles one sensor group, with OE controlled by PLC scan cycle phase to avoid bus collisions. Use Value: Eliminates mechanical relays or analog switches, improves long-term reliability, and maintains deterministic latency (<14 ns) across all 8 input channels. |
| Digital Test Equipment Signal Switching | Legacy Communication Interface Logic |
Use Scenario: Automated test fixtures requiring rapid reconfiguration of stimulus/response paths between DUT and measurement instruments. IC Role / Device Role / Timing Role: SN74AS253ADR functions as a programmable signal matrix - FPGA-generated A/B/OE signals dynamically assign DUT pins to oscilloscope inputs or pattern generators. Use Value: Achieves <15 ns path reconfiguration time, supports >50 MHz test clock rates, and replaces bulky relay-based switch matrices with solid-state reliability. | Use Scenario: Adapting UART, SPI, or parallel printer interface signals between legacy peripherals and modern controllers with mismatched pin counts. IC Role / Device Role / Timing Role: SN74AS253ADR performs protocol-specific signal remapping - e.g., selecting between RS-232 handshake lines or multiplexing printer status flags onto a shared interrupt line. Use Value: Enables drop-in replacement of obsolete interface ICs without redesign; AS-speed ensures compatibility with 115.2 kbps UART timing margins. |
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 |
|---|---|---|---|
| SN74ALS253DR | ALS family: slower (21 ns max tPHL), lower drive (24 mA IOL), higher ICC (12 mA active vs. 29 mA for SN74AS253ADR). | Suitable for cost-sensitive, lower-speed systems where propagation delay >20 ns is acceptable. | Choose when power efficiency and legacy compatibility outweigh speed requirements. |
| 74F253N | F-family: 10 ns max tPHL, 20 mA IOL, no 3-state outputs (standard totem-pole), different pinout (no separate OE pins). | Requires external tri-state logic or bus buffers; not pin-compatible with SN74AS253ADR. | Select only if board redesign accommodates non-3-state outputs and revised control signaling. |
Compared with SN74ALS253DR and 74F253N, SN74AS253ADR provides the highest speed and strongest drive in a pin-compatible 3-state SOIC package - making it optimal for bus-constrained, timing-critical upgrades without layout changes.
Availability
SN74AS253ADR is available at Aetrix Electronics and suitable for industrial control systems, test instrumentation, and legacy-computing hardware requiring stable component supply and guaranteed long-term sourcing.
Supply support for SN74AS253ADR 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 SN74AS253ADR belongs to TI's Advanced Schottky TTL logic family, engineered for high-speed digital signal routing in systems demanding robust noise immunity, precise timing, and direct TTL interoperability.
FAQ
What is the maximum operating frequency supported by the SN74AS253ADR?
The SN74AS253ADR does not specify a maximum clock frequency, but its 13.5 ns maximum propagation delay (A/B to Y) and 7 ns typical value support reliable operation in systems with signal periods ≥27 ns - corresponding to a practical upper limit near 37 MHz for synchronous multiplexing. Actual usable frequency depends on system-level timing margins, load capacitance, and OE assertion timing.
Can the SN74AS253ADR operate with a 3.3 V supply?
No, the SN74AS253ADR is specified only for 4.5 V to 5.5 V operation per its recommended conditions and absolute maximum ratings. Applying 3.3 V violates VIH/VIL thresholds (2.0 V/0.8 V) and risks unreliable logic transitions, increased propagation delay, or failure to meet output voltage specs (VOH/VOL). For 3.3 V systems, consider TI's LVC or AUP logic families instead.
How does the SN74AS253ADR handle bus contention when both outputs are enabled simultaneously?
The SN74AS253ADR does not prevent bus contention if both 1Y and 2Y are enabled (1OE = 2OE = low) while driving opposing logic states. Its design assumes only one output drives the bus at a time - proper system-level control (e.g., state machine or microcontroller sequencing) must ensure mutual exclusion. No internal arbitration or current-limiting is provided beyond standard TTL output structure.
Is the SN74AS253ADR RoHS compliant?
Yes, the SN74AS253ADR is RoHS compliant, as confirmed by Texas Instruments' packaging addendum: lead finish is NiPdAu (NIPDAU), and the part carries "Yes" under RoHS status. It meets EU Directive 2011/65/EU requirements with no exemptions applied, and is suitable for environmentally regulated commercial and industrial applications.
What is the thermal resistance (θJA) of the SN74AS253ADR in its SOIC-D package?
Texas Instruments does not publish θJA for the SN74AS253ADR in the SDAS216A datasheet. However, based on TI's standard SOIC-16 (D) package characterization, typical θJA is approximately 120°C/W under JEDEC JESD51-2 conditions (single-layer board, 1 in² copper). For thermal design, use worst-case ICC = 33 mA at VCC = 5.5 V to estimate power dissipation (~180 mW), then apply board-specific derating.
SN74AS253ADR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm 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-SOIC
SN74AS253ADR FAQ
1.How can I place an order for SN74AS253ADR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS253ADR 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 SN74AS253ADR reliable?
The price and inventory of SN74AS253ADR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS253ADR is usually 5 days.
3.What payment methods are accepted for SN74AS253ADR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS253ADR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS253ADR?
SN74AS253ADR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS253ADR 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 SN74AS253ADR?
For technical support, including SN74AS253ADR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS253ADR requirements.
6.How does Aetrix verify that SN74AS253ADR is sourced from the original manufacturer or authorized distributors?
All SN74AS253ADR 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 SN74AS253ADR meets industry standards.
7.What is the process for return or replacement of SN74AS253ADR?
All SN74AS253ADR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS253ADR, 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 SN74AS253ADR part is unused and in its original packaging.
Return procedure for SN74AS253ADR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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