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Texas Instruments SN54AS74AJ
- Part No.:
- SN54AS74AJ
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- -
- Datasheet:
-
SN54AS74AJ.pdf
- Description:
- 54AS74A DUAL POSITIVE-EDGE-TRIGG
- Quantity:
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Product details
Overview
SN54AS74AJ from Texas Instruments is a dual positive-edge-triggered D-type flip-flop IC designed for high-speed synchronous logic in military-grade systems. It operates across −55°C to 125°C, delivers 90 MHz clock frequency (CL = 50 pF), dissipates 26 mW per flip-flop, and features independent preset (PRE) and clear (CLR) inputs that override clock/data control. It is used in hardened timing control circuits such as radar pulse synchronization and avionics data latching.
For engineers reviewing the SN54AS74AJ datasheet, SN54AS74AJ pinout, SN54AS74AJ application, or SN54AS74AJ equivalent, key selection considerations include its military temperature rating, TTL-compatible input thresholds, guaranteed propagation delay under 10.5 ns, and ceramic dual-in-line (J) package hermetic sealing for reliability in harsh environments.
Technical Context
The SN54AS74AJ implements two independent edge-triggered D flip-flops with asynchronous active-low PRE and CLR inputs. Its AS-series architecture uses advanced Schottky-clamped bipolar transistors to achieve high speed without sacrificing noise immunity.
It supports true dual-latch operation: each section has dedicated CLK, D, PRE, CLR, Q, and Q̅ terminals, with no internal sharing between sections. Clock triggering responds to voltage threshold crossing-not edge slew rate-ensuring consistent timing across varying signal rise times.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Clock Frequency | 90 MHz max at CL = 50 pF - enables high-throughput state capture in real-time control loops. |
| Propagation Delay (tPLH/tPHL) | 2.5–10.5 ns - ensures sub-11 ns worst-case output response to clock or async control transitions. |
| Supply Voltage Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL power rails and tolerant of rail droop. |
| Input Voltage Thresholds | VIH = 2 V min, VIL = 0.8 V max - provides robust noise margin against TTL-level interference. |
| Output Drive Strength | IOL = 20 mA, IOH = −2 mA - directly interfaces with multiple TTL loads without buffering. |
| Operating Temperature | −55°C to 125°C - qualified for deployment in airborne, space, and ground-based defense platforms. |
| Power Dissipation | 10.5–16 mA ICC typical - balances speed and thermal management in sealed enclosures. |
Pinout & Package
Ceramic Dual-In-Line Package (CDIP), 14-pin, hermetically sealed with glass-frit lid (MIL-STD-1835 GDIP1-T14 compliant). Height ≤ 5.08 mm. Pin 1 identified by optional cap index point.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1CLR | Asynchronous active-low clear for first flip-flop - forces Q₁ = L, Q̅₁ = H independent of clock. |
| 2 | 1D | Data input for first flip-flop - sampled on rising CLK edge if PRE/CLR inactive. |
| 3 | 1CLK | Clock input for first flip-flop - triggers transfer only on voltage-threshold crossing (not edge slope). |
| 4 | 1PRE | Asynchronous active-low preset for first flip-flop - forces Q₁ = H, Q̅₁ = L regardless of clock. |
| 5 | 1Q | True output of first flip-flop - reflects stored D value after valid clock edge or async assertion. |
| 6 | 1Q̅ | Inverted output of first flip-flop - complementary to 1Q, usable for differential signaling or feedback. |
| 7 | GND | Ground reference - must be low-impedance return path for both logic sections and supply decoupling. |
| 8 | VCC | Positive supply - powers both flip-flops; requires local 0.1 µF ceramic decoupling at pin. |
| 9 | 2CLR | Asynchronous active-low clear for second flip-flop - independent control, no crosstalk with Section 1. |
| 10 | 2D | Data input for second flip-flop - electrically isolated from 1D; supports parallel or staggered latching. |
| 11 | 2CLK | Clock input for second flip-flop - may be driven separately or tied to 1CLK for synchronized operation. |
| 12 | 2PRE | Asynchronous active-low preset for second flip-flop - fully independent of Section 1 controls. |
| 13 | 2Q | True output of second flip-flop - usable for cascaded timing, state machine encoding, or bus arbitration. |
| 14 | 2Q̅ | Inverted output of second flip-flop - provides logical complement without external inverter. |
Key Features
| Feature | Design Value |
|---|---|
| High-Speed AS Logic | 90 MHz operation with <10.5 ns propagation delay - meets timing budgets in radar waveform generators and digital upconverters. |
| Full Military Temperature Range | −55°C to 125°C operation - validated for use in missile guidance electronics and satellite payload controllers. |
| Independent Asynchronous Controls | Dual PRE/CLR per section - enables atomic reset/preset of individual latches without disturbing adjacent logic states. |
| Hermetic Ceramic Package | J-package with glass-frit seal - prevents moisture ingress and ensures long-term reliability in high-humidity or vacuum environments. |
| TTL-Compatible Interface | VIH/VIL thresholds and IOL/IOH drive match legacy 5 V TTL systems - allows drop-in replacement in fielded hardware. |
Applications
| Radar Pulse Timing | Avionics Data Capture |
|---|---|
Use Scenario: Synchronizing transmit/receive switching in pulsed Doppler radar systems using precise clock-aligned latch windows. IC Role / Device Role / Timing Role: Dual D flip-flop latches radar trigger and echo-gate signals with sub-11 ns timing fidelity and deterministic setup/hold margins. Use Value: Eliminates metastability-induced timing jitter in critical RF control paths, ensuring accurate range bin alignment. | Use Scenario: Capturing sensor telemetry (e.g., inertial measurement unit outputs) during aircraft flight envelope monitoring. IC Role / Device Role / Timing Role: Provides hardened, temperature-stable edge-triggered storage for time-critical ADC samples before bus transmission. Use Value: Guarantees data integrity across extreme thermal cycling encountered in high-altitude flight profiles. |
| Military Communication Sync | Secure Crypto State Machine |
Use Scenario: Aligning frame boundaries in encrypted TDM voice/data links operating in electronic warfare environments. IC Role / Device Role / Timing Role: Acts as a dual-channel synchronizer to align incoming bit streams with local crypto clock domains. Use Value: Maintains bit-level alignment despite EMI-induced clock distortion, preventing decryption failure. | Use Scenario: Implementing finite-state logic for tamper-resistant cryptographic key derivation engines in secure modules. IC Role / Device Role / Timing Role: Stores intermediate state bits in a hardened, radiation-tolerant manner with glitch-free async reset. Use Value: Ensures deterministic state transitions under ionizing radiation exposure, meeting MIL-PRF-38535 Class B requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN54ALS74AJ | Lower max clock frequency (25 MHz), lower power (6 mW), slower propagation (≤23 ns). | Suitable for cost-sensitive, lower-speed military logic where thermal budget is constrained. | Select when speed is secondary to power efficiency and legacy ALS compatibility is required. |
| SNJ54AS74AJ | Identical electrical specs and pinout; differs only in TI's internal part numbering convention and qualification documentation traceability. | No functional or application difference - used interchangeably in QML-38535-compliant designs. | Preferred for new designs requiring full QML certification documentation and lot traceability per MIL-PRF-38535. |
Compared with SN54ALS74AJ, SN54AS74AJ delivers >3.5× higher clock rate and faster edge response but consumes ~2.7× more supply current; versus SNJ54AS74AJ, it shares identical performance and ruggedization - differing only in manufacturing pedigree and test reporting scope.
Availability
SN54AS74AJ is available at Aetrix Electronics and suitable for radar timing, avionics data capture, and secure crypto state machines requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN54AS74AJ 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 high-reliability logic solutions for aerospace, defense, and industrial markets.
The SN54AS74AJ belongs to TI's military-grade AS-series logic family, engineered for high-speed, low-skew digital control in mission-critical systems where environmental resilience and timing precision are non-negotiable.
FAQ
What is the maximum clock frequency supported by the SN54AS74AJ?
The SN54AS74AJ supports a maximum clock frequency of 90 MHz under recommended conditions (VCC = 4.5 V to 5.5 V, CL = 50 pF, TA = −55°C to 125°C). This value is based on characterization data per MIL-STD-833 Class B and is not production tested, but is guaranteed by TI's design validation for military applications. The SN54AS74AJ achieves this speed via its advanced Schottky-clamped bipolar process.
Does the SN54AS74AJ have separate power and ground pins for each flip-flop section?
No, the SN54AS74AJ uses a single shared VCC (Pin 8) and GND (Pin 7) for both flip-flop sections. This monolithic supply architecture simplifies PCB layout and reduces component count but requires careful local decoupling (e.g., 0.1 µF ceramic capacitor near Pin 8) to maintain noise immunity across the full −55°C to 125°C range. The SN54AS74AJ does not support split-rail or isolated power domains.
Can the preset and clear inputs of the SN54AS74AJ be used simultaneously on the same flip-flop?
No - asserting both PRE and CLR low on the same section (e.g., Pins 1 and 4 for Flip-Flop 1) results in an undefined, nonstable output state (Q and Q̅ both high), which is not guaranteed to meet VOH specifications and will revert unpredictably when either input returns high. The SN54AS74AJ datasheet explicitly warns against this condition; proper usage requires only one async control active at a time per section.
Is the SN54AS74AJ RoHS compliant?
The SN54AS74AJ is not RoHS compliant, as it is manufactured in a hermetic ceramic dual-in-line (J) package using leaded solder seals and traditional metallization processes required for military-grade reliability and MIL-STD-1835 compliance. TI classifies this device under "RoHS Exempt" per EU Directive Annex III exemptions for high-reliability aerospace and defense components. The SN54AS74AJ remains available for programs requiring legacy material content.
What is the function of Pin 7 (GND) and Pin 8 (VCC) in the SN54AS74AJ?
Pin 7 (GND) serves as the universal signal and power ground reference for both flip-flop sections and all input/output buffers in the SN54AS74AJ. Pin 8 (VCC) supplies +5 V DC power to the entire IC. These pins must be connected with low-inductance paths; TI recommends placing a 0.1 µF ceramic capacitor between Pin 8 and Pin 7 as close as possible to the SN54AS74AJ body to suppress high-frequency supply noise and ensure stable operation across temperature extremes.
SN54AS74AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- -
- Type:
- -
- Output Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Clock Frequency:
- -
- Max Propagation Delay @ V, Max CL:
- -
- Trigger Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Current - Quiescent (Iq):
- -
- Input Capacitance:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN54AS74AJ FAQ
1.How can I place an order for SN54AS74AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SN54AS74AJ 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 SN54AS74AJ reliable?
The price and inventory of SN54AS74AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN54AS74AJ is usually 5 days.
3.What payment methods are accepted for SN54AS74AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN54AS74AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN54AS74AJ?
SN54AS74AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN54AS74AJ 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 SN54AS74AJ?
For technical support, including SN54AS74AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN54AS74AJ requirements.
6.How does Aetrix verify that SN54AS74AJ is sourced from the original manufacturer or authorized distributors?
All SN54AS74AJ 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 SN54AS74AJ meets industry standards.
7.What is the process for return or replacement of SN54AS74AJ?
All SN54AS74AJ units undergo pre-shipment inspection (PSI). If there is an issue with SN54AS74AJ, 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 SN54AS74AJ part is unused and in its original packaging.
Return procedure for SN54AS74AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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