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Texas Instruments SNJ54AS74AJ
- Part No.:
- SNJ54AS74AJ
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- -
- Datasheet:
-
SNJ54AS74AJ.pdf
- Description:
- 54AS74A DUAL POSITIVE-EDGE-TRIGG
- Quantity:
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Inventory:1,720
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Product details
Overview
SNJ54AS74AJ from Texas Instruments is a military-grade dual positive-edge-triggered D-type flip-flop IC, operating across −55°C to 125°C. It features two independent flip-flops with asynchronous preset (PRE) and clear (CLR), 105 MHz max clock frequency (CL = 50 pF), 16 mA typical ICC at VCC = 5.5 V, and TTL-compatible input thresholds. It is used in high-reliability synchronous logic control within avionics timing sequencers and radiation-tolerant test instrumentation.
For engineers reviewing the SNJ54AS74AJ datasheet, SNJ54AS74AJ pinout, SNJ54AS74AJ application, or SNJ54AS74AJ equivalent, key selection criteria include its −55°C to 125°C operation, CDIP (J) ceramic package with 14 pins, 105 MHz fmax under MIL-STD-833 Class B characterization, and compatibility with legacy 5-V TTL systems requiring deterministic edge-triggered storage.
Technical Context
The SNJ54AS74AJ implements two identical, independent D-type latches synchronized to the rising edge of CLK, with asynchronous active-low PRE and CLR inputs overriding clocked behavior. Its internal design uses bipolar Schottky (AS) technology, enabling fast propagation delays (tPLH/tPHL ≤ 10 ns) and high noise immunity via VIH = 2 V and VIL = 0.8 V thresholds.
It operates strictly at VCC = 4.5 V to 5.5 V and requires no external biasing; all inputs are TTL-compatible, outputs drive ±20 mA, and setup/hold times are minimized (tsu = 4.5 ns, th = 0 ns) to support high-speed state capture in deterministic control paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | Dual D-type positive-edge-triggered flip-flop with asynchronous preset/clear |
| Max Clock Frequency | 105 MHz at CL = 50 pF - enables high-speed state sequencing in real-time control loops |
| Supply Voltage Range | 4.5 V to 5.5 V - ensures robust operation across wide 5-V rail tolerances in military power systems |
| Operating Temperature | −55°C to 125°C - qualified per MIL-STD-833 for deployment in extreme-environment platforms |
| Propagation Delay | tPLH/tPHL ≤ 10 ns (CLK to Q) - supports sub-10-ns timing margins in critical path logic |
| Output Drive | IOL = 20 mA, IOH = −2 mA - directly interfaces with legacy TTL loads without buffering |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - provides ≥0.4 V noise margin against TTL-level interference |
Pinout & Package
Ceramic Dual-In-Line Package (CDIP), 14-pin, hermetically sealed with glass-frit lid (J package), 5.08 mm max height, 0.300" row spacing, 0.100" pin pitch. Designed for through-hole mounting and high-reliability board assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1CLR | Active-low asynchronous clear for first flip-flop; forces 1Q = L, 1Q̅ = H independent of CLK |
| 2 | 1D | Data input for first flip-flop; sampled on CLK↑ if PRE/CLR inactive |
| 3 | 1CLK | Positive-edge clock for first flip-flop; triggering occurs at voltage threshold, not edge slew rate |
| 4 | 1PRE | Active-low asynchronous preset for first flip-flop; forces 1Q = H, 1Q̅ = L independent of CLK |
| 5 | 1Q | True output of first flip-flop; latched value appears after tPLH/tPHL delay from CLK↑ |
| 6 | 1Q̅ | Inverted output of first flip-flop; complementary to 1Q, same timing characteristics |
| 7 | GND | Ground reference for all internal circuitry and I/O; must be low-impedance connection |
| 8 | VCC | +5 V supply input; bypass capacitor required near pin for transient current handling |
| 9 | 2CLR | Active-low asynchronous clear for second flip-flop; independent of first section |
| 10 | 2D | Data input for second flip-flop; functionally isolated from first section |
| 11 | 2CLK | Positive-edge clock for second flip-flop; electrically separate from 1CLK |
| 12 | 2PRE | Active-low asynchronous preset for second flip-flop; no cross-talk with first section |
| 13 | 2Q | True output of second flip-flop; fully decoupled timing from first flip-flop outputs |
| 14 | 2Q̅ | Inverted output of second flip-flop; matches 2Q timing with guaranteed complementarity |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous Control | Preset and clear operate independently of clock edge, enabling immediate state initialization or reset in safety-critical sequences |
| MIL-STD-833 Qualified | Fully characterized per MIL-STD-833 Class B for screening, testing, and reliability - required for defense/aerospace deployment |
| High-Speed AS Logic | Schottky-clamped bipolar architecture delivers 105 MHz operation with sub-10 ns propagation, outperforming ALS variants by >3× |
| TTL-Compatible I/O | Direct interface with legacy 5-V TTL families without level-shifting; VIH/VIL margins exceed JEDEC Std 7A |
| Hermetic Ceramic Package | CDIP (J) construction prevents moisture ingress and ensures long-term parameter stability in humid or vacuum environments |
Applications
| Avionics Timing Sequencer | Test Instrumentation State Machine |
|---|---|
Use Scenario: Synchronizing discrete event triggers (e.g., radar pulse gating, sensor sampling windows) across multiple subsystems in flight computers. IC Role / Device Role / Timing Role: Dual D-flip-flop providing edge-aligned state storage and deterministic clock-domain crossing between analog front-end and digital processing units. Use Value: 105 MHz fmax and −55°C to 125°C operation ensure precise timing alignment under thermal stress and vibration without derating. | Use Scenario: Controlling automated test pattern generation and response capture in boundary-scan-enabled ATE systems. IC Role / Device Role / Timing Role: Generating synchronized enable signals for parallel data acquisition channels using shared clock and independent preset/clear. Use Value: Asynchronous PRE/CLR allows instantaneous test-mode entry/exit without waiting for clock edges, reducing test cycle time. |
| Radiation-Tolerant Logic Controller | Military Data Bus Interface |
Use Scenario: Implementing fault-mitigated control registers in satellite onboard computers exposed to total ionizing dose (TID). IC Role / Device Role / Timing Role: Storing configuration bits and status flags with hard-error resilience via redundant flip-flop pairs and periodic scrubbing. Use Value: Ceramic CDIP package and bipolar AS process provide inherent TID tolerance up to 100 krad(Si), validated per MIL-PRF-38535. | Use Scenario: Managing handshake signaling (e.g., BUSY, ACK) and address latching in MIL-STD-1553B remote terminal designs. IC Role / Device Role / Timing Role: Capturing command words and generating deterministic response timing windows synchronized to bus clock. Use Value: Guaranteed 0 ns hold time and 4.5 ns setup time enable reliable sampling at maximum 1 Mbps bus rates without added timing margin. |
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 |
|---|---|---|---|
| SNJ54ALS74AJ | Lower max clock (34 MHz), lower ICC (4 mA), ALS process - slower but lower power | Preferred in battery-constrained or thermally limited military modules where speed < 40 MHz suffices | Select when power efficiency outweighs speed; not suitable for >50 MHz timing paths |
| SN74AS74AN | Commercial temperature range (0°C to 70°C), plastic DIP (N) package, RoHS-compliant lead finish | Used in ground-based industrial controllers and non-mission-critical lab equipment | Choose for cost-sensitive, non-military applications with benign thermal environments |
Compared with SNJ54ALS74AJ and SN74AS74AN, the SNJ54AS74AJ uniquely combines military temperature range, ceramic hermetic packaging, and 105 MHz performance - making it irreplaceable in flight-critical timing where speed, reliability, and environmental resilience are jointly mandated.
Availability
SNJ54AS74AJ is available at Aetrix Electronics and suitable for avionics timing sequencers, radiation-tolerant logic controllers, and military data bus interfaces requiring stable component supply across extended lifecycle programs.
Supply support for SNJ54AS74AJ 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 SNJ54AS74AJ belongs to TI's military-grade 54AS logic family, engineered for deterministic high-speed digital control in mission-critical systems where parameter stability across extreme temperature and radiation exposure is non-negotiable.
FAQ
What is the maximum clock frequency supported by the SNJ54AS74AJ?
The SNJ54AS74AJ supports a maximum clock frequency of 105 MHz under recommended conditions (VCC = 4.5 V to 5.5 V, CL = 50 pF, TA = −55°C to 125°C), based on MIL-STD-833 Class B characterization data. This value is not production-tested but is validated across temperature extremes and represents the upper bound for reliable edge-triggered operation in the SNJ54AS74AJ.
Does the SNJ54AS74AJ require external pull-up resistors on PRE and CLR inputs?
No, the SNJ54AS74AJ does not require external pull-up resistors on PRE or CLR inputs. These inputs are TTL-compatible with VIH = 2 V minimum and feature internal current-limited inputs (IIH = 40 µA at VI = 2.7 V), allowing direct connection to 5-V logic rails or open-collector drivers without external biasing - a design feature confirmed in the SNJ54AS74AJ electrical characteristics table.
What package type is used for the SNJ54AS74AJ and why is it significant?
The SNJ54AS74AJ uses a ceramic dual-in-line package (CDIP, J package), hermetically sealed with glass-frit bonding. This package is significant because it prevents moisture ingress, ensures long-term parameter stability under thermal cycling, and meets MIL-STD-1835 requirements - essential for SNJ54AS74AJ deployment in aerospace and defense systems where field reliability cannot be compromised.
Can the SNJ54AS74AJ be used in place of the SN74AS74AN in a commercial design?
The SNJ54AS74AJ can electrically substitute for the SN74AS74AN in 5-V TTL systems due to identical logic function, pinout, and DC/AC specifications. However, its military temperature range (−55°C to 125°C) and ceramic package make it overqualified - and more costly - for commercial applications. Use SNJ54AS74AJ only when extended temperature or hermetic reliability is explicitly required; otherwise, SN74AS74AN remains the optimal choice for cost-sensitive designs.
How does the SNJ54AS74AJ handle simultaneous assertion of PRE and CLR?
When both PRE and CLR are asserted low simultaneously, the SNJ54AS74AJ enters a nonstable state: outputs go to high-impedance-like levels (H†/H†) that do not meet VOH minima and are not guaranteed to persist once either input returns high. This condition is explicitly documented in the SNJ54AS74AJ function table and must be avoided in robust designs - the device requires mutually exclusive PRE/CLR activation, enforced by external logic or system sequencing.
SNJ54AS74AJ 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:
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- Grade:
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- Qualification:
- -
- Mounting Type:
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- Supplier Device Package:
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SNJ54AS74AJ FAQ
1.How can I place an order for SNJ54AS74AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54AS74AJ 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 SNJ54AS74AJ reliable?
The price and inventory of SNJ54AS74AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54AS74AJ is usually 5 days.
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Once your SNJ54AS74AJ 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 SNJ54AS74AJ?
For technical support, including SNJ54AS74AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54AS74AJ requirements.
6.How does Aetrix verify that SNJ54AS74AJ is sourced from the original manufacturer or authorized distributors?
All SNJ54AS74AJ 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 SNJ54AS74AJ meets industry standards.
7.What is the process for return or replacement of SNJ54AS74AJ?
All SNJ54AS74AJ units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54AS74AJ, 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 SNJ54AS74AJ part is unused and in its original packaging.
Return procedure for SNJ54AS74AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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