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Texas Instruments SN74AS298ADR
- Part No.:
- SN74AS298ADR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS298ADR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,191
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Product details
Overview
SN74AS298ADR from Texas Instruments is a quadruple 2-input multiplexer with synchronous storage, functioning as a dual 4-bit selectable register with clocked output latching. It supports dual-source operand selection (A1/B1/C1/D1 or A2/B2/C2/D2) via word-select (WS), clocks data on CLK negative edge, and operates at up to 62 MHz across 0°C to 70°C. It enables parallel-load shift-register operation in arithmetic processors and ALU support circuits.
For engineers reviewing the SN74AS298ADR datasheet, SN74AS298ADR pinout, SN74AS298ADR application, or SN74AS298ADR equivalent, key selection criteria include its dual-word synchronous latch behavior, 16-pin SOIC-D package, TTL-compatible 5-V operation, negative-edge clocking, and use in BCD/binary shift registers and register-file offload architectures.
Technical Context
The SN74AS298ADR integrates two functional blocks - a 4-bit 2:1 multiplexer and a 4-bit D-type flip-flop array - into a single 16-pin device. Its WS input selects between two independent 4-bit input words, and the CLK signal (negative-edge triggered) simultaneously latches the selected word into QA–QD outputs.
This architecture replaces discrete combinations of SN74AS157 (quad 2-input mux) and SN74AS175A (quad D flip-flop), reducing board space and interconnect complexity. Timing parameters are specified for CL = 50 pF, with tPLH/tPHL propagation delays of 2–9 ns and 1–11 ns respectively, supporting high-speed synchronous data routing in legacy TTL systems.
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 logic rails and noise margin compliance. |
| Max Clock Frequency | 62 MHz - enables high-throughput operand switching in arithmetic pipelines without timing violation. |
| Propagation Delay (tPLH / tPHL) | 2–9 ns / 1–11 ns - defines worst-case setup-to-output timing for synchronous register update within tight control cycles. |
| Output Drive (IOL / IOH) | 20 mA sink / −2 mA source - supports direct fanout to multiple 74AS inputs without buffering. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded control and industrial computing environments. |
| Input Thresholds (VIH / VIL) | 2.0 V / 0.8 V - matches standard TTL voltage levels, ensuring interoperability with legacy 74LS/74AS families. |
Pinout & Package
SN74AS298ADR is supplied in a 16-pin SOIC (D) package with 1.27 mm pitch, 10.3 mm × 5.3 mm body, and RoHS-compliant NiPdAu lead finish (MSL Level-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | B2 | Second-word bit-B input - selected when WS = HIGH; connects to secondary operand bus. |
| 2 | A2 | Second-word bit-A input - active during WS = HIGH; used for dual-ALU result routing. |
| 3 | A1 | First-word bit-A input - selected when WS = LOW; typically tied to primary register file output. |
| 4 | B1 | First-word bit-B input - active during WS = LOW; supports parallel load of first operand set. |
| 5 | C2 | Second-word bit-C input - part of 4-bit word-2 group; enables full 4-bit synchronous transfer. |
| 6 | D2 | Second-word bit-D input - completes word-2 input set; required for BCD digit shifting applications. |
| 7 | D1 | First-word bit-D input - completes word-1 input set; used in register exchange and load operations. |
| 8 | GND | Power ground reference - must be low-impedance connection to minimize switching noise coupling. |
| 9 | VCC | +5 V supply rail - decoupling capacitor (0.1 µF ceramic) required adjacent to pin for stable high-speed operation. |
| 10 | QA | Word-selected output A - latched on CLK↓; drives downstream ALU or shifter stage directly. |
| 11 | QB | Word-selected output B - synchronized with QA; maintains bit-group timing integrity. |
| 12 | QC | Word-selected output C - provides third bit of latched 4-bit word; critical for multi-digit BCD shift. |
| 13 | QD | Word-selected output D - final bit of latched word; used in carry-chain or overflow detection paths. |
| 14 | CLK | Clock input - negative-edge sensitive; triggers simultaneous latching of all four QA–QD outputs. |
| 15 | WS | Word-select control - HIGH selects A2/B2/C2/D2; LOW selects A1/B1/C1/D1; determines operand source. |
| 16 | C1 | First-word bit-C input - completes first 4-bit operand group; essential for register-to-register exchange. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 4-bit word selection with synchronous latch | Eliminates need for separate mux + register ICs, reducing component count and PCB area in arithmetic units. |
| Negative-edge clock triggering | Enables precise alignment with system clock domains where falling-edge sampling is required for pipeline staging. |
| 62-MHz maximum clock rate | Supports real-time operand switching in high-speed ALUs without introducing pipeline stalls or wait states. |
| TTL-compatible input thresholds and drive strength | Guarantees interoperability with existing 74AS/74ALS logic families without level-shifting circuitry. |
| SOIC-D package with MSL Level-1 rating | Enables standard reflow assembly in commercial manufacturing without moisture-sensitive handling constraints. |
Applications
| Arithmetic Processor Operand Switching | BCD Digit Shift Register |
|---|---|
|
Use Scenario: Arithmetic processor requires rapid alternation between two operand sources (e.g., register file vs. immediate constant bus) during instruction execution. IC Role / Device Role / Timing Role: SN74AS298ADR acts as a synchronous operand selector and latch, enabling zero-cycle operand changeover on CLK↓. Use Value: Frees register file bandwidth by allowing concurrent fetch of new operands while previous ones are processed, improving IPC. |
Use Scenario: Industrial BCD display controller shifts entire 4-bit digits left/right for scrolling or alignment without software overhead. IC Role / Device Role / Timing Role: SN74AS298ADR implements a universal 4-bit shift register using WS-controlled word routing and CLK↓ latching. Use Value: Achieves single-pulse digit-level shift (e.g., "1234" → "2340") with no microcontroller intervention or clock cycle penalty. |
| ALU Result Multiplexing | Parallel-Load Register Exchange |
|
Use Scenario: Multi-ALU system routes results from two independent arithmetic units to shared accumulator or memory interface. IC Role / Device Role / Timing Role: SN74AS298ADR serves as a result bus selector, gated by ALU-ready signals mapped to WS. Use Value: Enables time-multiplexed ALU result capture with deterministic latency, avoiding arbitration logic or FIFO buffers. |
Use Scenario: Embedded controller implements bidirectional register swap (e.g., R1 ↔ R2) for context switching or data rotation. IC Role / Device Role / Timing Role: SN74AS298ADR functions as a dual-port register with external load capability via WS and CLK coordination. Use Value: Allows full 4-bit register exchange in one clock cycle while retaining ability to load new data externally - no extra control states needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-bit synchronous multiplexer/register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS157D + SN74AS175N | Two discrete ICs: quad 2:1 mux + quad D flip-flop; identical logic function but larger footprint and higher interconnect count. | Requires additional PCB area and routing; suitable only when SOIC-D package is unavailable or mixed-package sourcing is preferred. | Select when board layout allows separation of mux and latch functions or when inventory already includes both components. |
| SN74F298N | F-family version: lower speed (30 MHz max), higher power (ICCL ≈ 45 mA), wider propagation delay (tPLH up to 15 ns). | Acceptable for cost-sensitive, lower-speed systems where 62 MHz timing is not required and thermal budget permits higher dissipation. | Choose for legacy F-series designs where pinout compatibility exists and performance margin allows 50% speed reduction. |
Compared with SN74AS298ADR, SN74AS157D+SN74AS175N increases board area and signal path length, while SN74F298N trades speed and power efficiency for broader availability in older inventory channels - neither offers drop-in replacement without validation.
Availability
SN74AS298ADR is available at Aetrix Electronics and suitable for arithmetic processor design, BCD display control, ALU result routing, and register-exchange subsystems requiring stable component supply and long-term commercial-temperature support.
Supply support for SN74AS298ADR 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 SN74AS298ADR belongs to TI's 74AS advanced Schottky TTL logic family, engineered for high-speed, low-noise digital control in commercial computing and instrumentation systems.
FAQ
What is the primary function of the SN74AS298ADR in a digital system?
The SN74AS298ADR functions as a synchronous 4-bit dual-word multiplexer with integrated storage, selecting between two 4-bit input groups (A1–D1 or A2–D2) based on the WS signal and latching the chosen word to QA–QD outputs on the negative edge of CLK. This enables operand switching, register exchange, and shift-register behavior in arithmetic and control logic - all within a single 16-pin SOIC package.
Does the SN74AS298ADR support 3.3-V operation?
No, the SN74AS298ADR is specified only for 4.5 V to 5.5 V supply operation and is not compatible with 3.3-V logic families. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output drive characteristics are optimized for 5-V TTL systems. Interfacing with 3.3-V devices requires level translation circuitry to prevent overvoltage or logic misinterpretation.
How does the word-select (WS) input affect timing behavior in the SN74AS298ADR?
The WS input determines which 4-bit word is sampled and latched on the next CLK↓ transition, with a minimum setup time (tsu) of 13 ns and hold time (th) of 1 ns relative to CLK↓. Changing WS after tsu but before th violates timing and may cause metastability or indeterminate output. Stable WS state must be maintained across the CLK↓ sampling window to ensure reliable word selection.
Can the SN74AS298ADR be used as a standalone shift register without external logic?
Yes - the SN74AS298ADR can implement a 4-bit universal shift register using feedback connections: QD→A1, QC→B1, QB→C1, QA→D1, and WS controlled to sequence shifts. As shown in TI's Application Information (Figure 1), this configuration achieves single-clock-pulse BCD digit shifting while retaining parallel-load capability via WS and CLK coordination.
What is the significance of the "D" suffix in SN74AS298ADR?
"D" denotes the SOIC (Small-Outline Integrated Circuit) package type per TI's packaging nomenclature. The "R" suffix indicates tape-and-reel packaging (as opposed to "TUBE"), though the SN74AS298ADR datasheet confirms tube packaging for the D variant - the "R" in this case reflects distributor-specific ordering code rather than physical packaging format. Always verify packaging format via orderable part number (e.g., SN74AS298AD = SOIC-D, tube).
SN74AS298ADR 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:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 2mA, 20mA
- 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
SN74AS298ADR FAQ
1.How can I place an order for SN74AS298ADR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS298ADR 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 SN74AS298ADR reliable?
The price and inventory of SN74AS298ADR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS298ADR is usually 5 days.
3.What payment methods are accepted for SN74AS298ADR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS298ADR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS298ADR?
SN74AS298ADR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS298ADR 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 SN74AS298ADR?
For technical support, including SN74AS298ADR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS298ADR requirements.
6.How does Aetrix verify that SN74AS298ADR is sourced from the original manufacturer or authorized distributors?
All SN74AS298ADR 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 SN74AS298ADR meets industry standards.
7.What is the process for return or replacement of SN74AS298ADR?
All SN74AS298ADR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS298ADR, 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 SN74AS298ADR part is unused and in its original packaging.
Return procedure for SN74AS298ADR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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